feat(dashboard): Recent activity events route to entity by kind

SP21 Task 2.5 — the Dashboard's 'Recent activity' card now routes clicks
to the matching entity drawer / page by event kind:

  - claim_*       → /claims?claim=<id>  (drawer in Phase 5)
  - provider_added → /providers?provider=<npi>  (ProviderDrawer)
  - remit_received → toast 'coming in a later phase' (RemitDrawer in Phase 4)
  - anything else  → toast (manual_match, unknown kinds)

Implementation:
  - New src/lib/event-routing.ts with the eventKindToUrl() helper,
    plus a unit test covering all 6 + default branches.
  - src/components/ActivityFeed.tsx gains an optional onItemClick
    prop; when set, each row gets role='button', tabIndex=0, the
    drillable hover affordance (chevron + tint), and an Enter/Space
    keybinding. e.stopPropagation() is called before the handler so a
    parent row click can't double-fire (same fix as Task 2.4).
  - src/pages/Dashboard.tsx wires the handler on the 'Recent activity'
    card via eventKindToUrl + sonner toast for unhandled kinds.
  - Backend: CycloneStore.recent_activity() now exposes claimId and
    remittanceId on each row (read from ActivityEvent.claim_id /
    remittance_id) so the routing helper has the entity ids it needs.
  - The frontend Activity interface gains optional claimId /
    remittanceId fields; the in-memory sample data and the
    addClaim store action populate them so the dashboard works in
    both API-configured and sample-data modes.

README.md

@@ -51,6 +51,32 @@ VITE_API_BASE_URL=http://127.0.0.1:8000
 Without that, the UI falls back to its in-memory sample store via the
 existing `data` adapter (parses are disabled).
 
+## Pipeline automation agent
+
+For unattended round-trips (an agent / scheduler drops an 837P file
+into the pipeline and waits for the 999 back from Gainwell), see the
+`cyclone-pipeline` sibling project at `/Users/openclaw/dev/cyclone-pipeline/`.
+It drives the full 7-phase state machine — preflight → browser upload →
+parse verification → SFTP submit → TA1 wait → 999 wait → scan +
+report — with structured JSON logs, crash-safe resume, and a
+self-contained per-run folder under `./runs/`.
+
+```bash
+# Single file
+cyclone-pipeline run /path/to/axiscare-837p.txt
+
+# Resume a crashed run
+cyclone-pipeline resume 2026-06-21-1430-001
+
+# On/after the following Monday, verify the 835 arrived
+cyclone-pipeline check-835 2026-06-21-1430-001
+```
+
+The 835 is **not** waited for inline (it lands the following Monday on
+the CO Medicaid payment cycle). See
+[`cyclone-pipeline/README.md`](../cyclone-pipeline/README.md) for
+install, embed-in-agent example, exit codes, and the report format.
+
 ## Skills
 
 Cyclone ships 8 project-scoped AI-assistant skills under
@@ -743,6 +769,17 @@ scope.
 
 Shipped sub-projects (most recent first):
 
+- **Sub-project 22 (shipped) — Pipeline automation agent.** A
+  sibling project at `/Users/openclaw/dev/cyclone-pipeline` that
+  drives the full 7-phase round-trip (preflight → browser upload →
+  parse verify → SFTP submit → TA1 wait → 999 wait → scan + report)
+  with crash-safe resume, structured JSON logging, idempotency
+  dedup, and a per-run report. Pure Python 3.11+ (httpx, Playwright,
+  Click, pydantic v2, structlog). The 835 is not waited for inline —
+  it lands the following Monday — and is verified by a separate
+  `check-835` subcommand. Embeddable as a library for OpenClaw / Nora
+  agent integration. See
+  [Pipeline automation agent](#pipeline-automation-agent) above.
 - **Sub-project 19 (shipped) — Security hardening + health probe.**
   Three pure-ASGI middlewares (`BodySizeLimitMiddleware`,
   `RateLimitMiddleware`, `SecurityHeadersMiddleware`) close the

backend/src/cyclone/api.py

@@ -9,8 +9,11 @@ The frontend (Vite/React on http://localhost:5173) uploads an X12 file via
   — one envelope, one line per claim/payout, then one summary — so the
   UI can render records incrementally as they're produced.
 
-CORS is configured to allow the Vite dev origin (``http://localhost:5173``)
-plus GET/POST with any header.
+CORS is configured to allow the Vite dev origins (``http://localhost:5173``
+and ``http://127.0.0.1:5173`` — both forms are valid dev-server addresses
+but CORS treats them as distinct origins) plus GET/POST with any header.
+Additional origins (LAN IPs, staging hosts) can be appended via the
+``CYCLONE_ALLOWED_ORIGINS`` env var as a comma-separated list.
 """
 
 from __future__ import annotations
@@ -19,9 +22,11 @@ import csv
 import io
 import json
 import logging
+import os
 import uuid
 from datetime import datetime, timezone
 from contextlib import asynccontextmanager
+from time import monotonic
 from typing import Any, AsyncIterator
 
 from fastapi import FastAPI, File, HTTPException, Query, Request, UploadFile
@@ -31,6 +36,8 @@ from pydantic import ValidationError
 
 from cyclone import __version__, db
 from cyclone.db import Claim, ClaimState, Remittance
+from sqlalchemy import desc, or_
+from sqlalchemy.exc import IntegrityError
 from cyclone.inbox_state import apply_999_rejections
 from cyclone.inbox_state_277ca import apply_277ca_rejections
 from cyclone.audit_log import AuditEvent, append_event, verify_chain
@@ -212,7 +219,17 @@ PAYER_FACTORIES_835: dict[str, Any] = {
     "generic_835": PayerConfig835.generic_835,
 }
 
-VITE_DEV_ORIGIN = "http://localhost:5173"
+# Allow both common dev-server origins. ``localhost`` and ``127.0.0.1``
+# resolve to the same Vite dev server but CORS treats them as distinct
+# origins, so the allow-list has to list both — otherwise a tab opened
+# via the IP form gets blocked even though the dev server is identical.
+VITE_DEV_ORIGINS: list[str] = [
+    "http://localhost:5173",
+    "http://127.0.0.1:5173",
+]
+_extra_origins = os.environ.get("CYCLONE_ALLOWED_ORIGINS", "").strip()
+if _extra_origins:
+    VITE_DEV_ORIGINS.extend(o.strip() for o in _extra_origins.split(",") if o.strip())
 
 app = FastAPI(
     title="Cyclone 837P / 835 Parser API",
@@ -223,7 +240,7 @@ app = FastAPI(
 
 app.add_middleware(
     CORSMiddleware,
-    allow_origins=[VITE_DEV_ORIGIN],
+    allow_origins=VITE_DEV_ORIGINS,
     allow_credentials=False,
     allow_methods=["GET", "POST"],
     allow_headers=["*"],
@@ -280,6 +297,35 @@ def _resolve_payer_835(name: str) -> PayerConfig835:
     return PAYER_FACTORIES_835[name]()
 
 
+# --------------------------------------------------------------------------- #
+# Catch-all exception handler
+# --------------------------------------------------------------------------- #
+#
+# Without this, any exception that escapes a route handler is rendered by
+# Uvicorn as a bare ``500 Internal Server Error`` text/plain response with
+# NO CORS headers. Browsers reading such a response report it as a CORS
+# error (``Origin ... is not allowed by Access-Control-Allow-Origin``)
+# because they cannot read the body without the CORS allow-origin header
+# — even though the actual failure was on the server. We catch everything
+# here, log it, and return a JSON error with the request's Origin echoed
+# back so the browser can surface the real message.
+@app.exception_handler(Exception)
+async def _unhandled_exception_handler(request: Request, exc: Exception) -> JSONResponse:
+    log.exception(
+        "Unhandled exception in %s %s", request.method, request.url.path
+    )
+    headers: dict[str, str] = {}
+    origin = request.headers.get("origin", "")
+    if origin:
+        headers["Access-Control-Allow-Origin"] = origin
+        headers["Vary"] = "Origin"
+    return JSONResponse(
+        status_code=500,
+        content={"error": "Internal server error", "detail": str(exc)},
+        headers=headers,
+    )
+
+
 @app.post("/api/parse-837")
 async def parse_837(
     request: Request,
@@ -343,7 +389,30 @@ async def parse_837(
         parsed_at=utcnow(),
         result=result,
     )
-    store.add(rec, event_bus=request.app.state.event_bus)
+    try:
+        store.add(rec, event_bus=request.app.state.event_bus)
+    except IntegrityError as exc:
+        # ``(batch_id, patient_control_number)`` is UNIQUE — fires when a
+        # single batch file contains the same CLM01 control number twice,
+        # or when the same claim id has already been ingested in a prior
+        # batch. Surface as 409 with the batch id so the caller can look
+        # it up; do NOT 500 (a 500 without CORS headers is misreported by
+        # browsers as a CORS error and hides the real cause).
+        log.warning("Duplicate claim while persisting batch %s: %s", rec.id, exc)
+        return JSONResponse(
+            status_code=409,
+            content={
+                "error": "Duplicate claim",
+                "detail": (
+                    "This file (or one previously ingested with the same "
+                    "claim control number) collides with an existing "
+                    "record. Inspect the file for duplicate CLM01 "
+                    "control numbers, or remove the existing batch "
+                    "before retrying."
+                ),
+                "batch_id": rec.id,
+            },
+        )
 
     if _client_wants_json(request):
         body = json.loads(result.model_dump_json())
@@ -514,7 +583,23 @@ async def parse_835_endpoint(
         parsed_at=utcnow(),
         result=result,
     )
-    store.add(rec, event_bus=request.app.state.event_bus)
+    try:
+        store.add(rec, event_bus=request.app.state.event_bus)
+    except IntegrityError as exc:
+        log.warning("Duplicate remittance while persisting batch %s: %s", rec.id, exc)
+        return JSONResponse(
+            status_code=409,
+            content={
+                "error": "Duplicate remittance",
+                "detail": (
+                    "This 835 file (or one previously ingested with the "
+                    "same payer claim control number) collides with an "
+                    "existing record. Remove the existing remittance "
+                    "before retrying."
+                ),
+                "batch_id": rec.id,
+            },
+        )
 
     if _client_wants_json(request):
         body = json.loads(result.model_dump_json())
@@ -2933,7 +3018,73 @@ def get_configured_provider(npi: str):
     p = store.get_provider(npi)
     if p is None:
         raise HTTPException(status_code=404, detail=f"provider {npi!r} not found")
-    return json.loads(p.model_dump_json())
+    provider_dict = json.loads(p.model_dump_json())
+
+    # SP21 Task 1.6: extend the response with two top-N arrays that the
+    # drill-down peek panel hangs off. ``recent_claims`` reuses the
+    # existing store projection (already returns UI-shaped dicts with
+    # ``submissionDate``); ``recent_activity`` is a direct ORM join
+    # because ``ActivityEvent`` has no ``provider_npi`` column — the
+    # filter has to hop through ``Claim.id``.
+    recent_claims = sorted(
+        store.iter_claims(provider_npi=npi),
+        key=lambda c: c.get("submissionDate") or "",
+        reverse=True,
+    )[:10]
+
+    # Activity filter has TWO join paths back to a Claim for this
+    # provider:
+    #   1. ``ActivityEvent.claim_id IN (claim_ids)`` — events that were
+    #      recorded with a claim FK already set (claim_submitted,
+    #      manual_match, claim_paid, etc.).
+    #   2. ``Remittance.claim_id IN (claim_ids)`` — the original
+    #      ``remit_received`` event recorded at 835 ingest time
+    #      (``store.add`` lines 999-1003) is inserted with
+    #      ``claim_id=None`` because the remittance hasn't been matched
+    #      to a claim yet. The auto-reconcile pass later sets
+    #      ``Remittance.claim_id`` (``reconcile.run`` lines 289-293),
+    #      but the *original* ActivityEvent row stays orphaned. The
+    #      outer-join-then-OR lets us surface both shapes. Without
+    #      path 2, a provider's activity feed looks frozen the moment
+    #      an 835 lands — the most common activity, invisible.
+    with db.SessionLocal()() as s:
+        claim_ids = [
+            cid
+            for (cid,) in s.query(Claim.id)
+            .filter(Claim.provider_npi == npi)
+            .all()
+        ]
+        activity_rows = []
+        if claim_ids:
+            activity_rows = (
+                s.query(db.ActivityEvent)
+                .outerjoin(
+                    Remittance,
+                    db.ActivityEvent.remittance_id == Remittance.id,
+                )
+                .filter(or_(
+                    db.ActivityEvent.claim_id.in_(claim_ids),
+                    Remittance.claim_id.in_(claim_ids),
+                ))
+                .order_by(desc(db.ActivityEvent.ts))
+                .limit(10)
+                .all()
+            )
+
+    def _activity_to_ui(a):
+        return {
+            "id": a.id,
+            "ts": a.ts.isoformat().replace("+00:00", "Z") if a.ts else "",
+            "kind": a.kind,
+            "batchId": a.batch_id,
+            "claimId": a.claim_id,
+            "remittanceId": a.remittance_id,
+            "payload": a.payload_json or {},
+        }
+
+    provider_dict["recent_claims"] = recent_claims
+    provider_dict["recent_activity"] = [_activity_to_ui(a) for a in activity_rows]
+    return provider_dict
 
 
 @app.get("/api/config/payers")
@@ -2958,6 +3109,126 @@ def list_payer_configs(payer_id: str):
     return configs
 
 
+# --------------------------------------------------------------------------- #
+# SP21 Task 1.5: payer-level summary for the drill-down panel
+# --------------------------------------------------------------------------- #
+
+# Per-payer_id memoization for /api/payers/{payer_id}/summary. The drill-
+# down UI hammers this on every hover; the underlying query is O(claims)
+# per payer so a 60s TTL keeps the panel responsive. Process-local on
+# purpose — invalidation is driven by the TTL alone for now (see note
+# below).
+_SUMMARY_TTL_S = 60.0
+_summary_cache: dict[str, tuple[float, dict]] = {}
+
+
+def _clear_summary_cache() -> None:
+    """Test hook: wipe the process-local cache.
+
+    The 60s TTL means tests that want to assert on a recomputed payload
+    must clear the cache between requests. Not used by production code.
+    """
+    _summary_cache.clear()
+
+
+# Pubsub invalidation is intentionally NOT wired. The ``claim_written``
+# and ``remittance_written`` payloads emitted by ``store.add`` are the
+# UI-shaped dicts from ``to_ui_claim_from_orm`` / ``to_ui_remittance_from_orm``,
+# neither of which carries the X12 ``payer_id`` (NM1*PR*PI qualifier).
+# They carry ``payerName`` only, which is the human-readable name and not
+# the URL key we cache on. Wiring a subscriber here would either need a
+# DB lookup per event (re-deriving payer_id from Claim.id) or a different
+# cache key — both are out of scope for this task. The 60s TTL keeps
+# staleness bounded; a follow-up can wire targeted invalidation if the
+# UI proves TTL-bounded staleness is unacceptable.
+
+
+@app.get("/api/payers/{payer_id}/summary")
+def get_payer_summary(payer_id: str):
+    """Payer-level rollup for the drill-down panel.
+
+    Returns billed/received totals, denial rate, and top providers for
+    the given ``payer_id`` (the X12 NM1*PR*PI qualifier, e.g. ``SKCO0``).
+    Cached in-process for ``_SUMMARY_TTL_S`` seconds.
+
+    404 when no claims AND no remits reference this payer_id — the UI
+    uses that to distinguish a typo from a payer with zero traffic
+    (the latter would still return a valid 200 with zeroed totals).
+    """
+    now = monotonic()
+    cached = _summary_cache.get(payer_id)
+    if cached and (now - cached[0]) < _SUMMARY_TTL_S:
+        return cached[1]
+
+    log.debug("payer summary cache miss", extra={"payer_id": payer_id})
+
+    # Query claims + remits scoped to this payer_id. We bypass
+    # ``store.iter_claims`` because that helper filters by payer NAME
+    # substring, not by the X12 PI qualifier we use as the URL key.
+    with db.SessionLocal()() as s:
+        claim_rows: list[Claim] = (
+            s.query(Claim).filter(Claim.payer_id == payer_id).all()
+        )
+        claim_ids = [c.id for c in claim_rows]
+        remit_rows: list[Remittance] = []
+        if claim_ids:
+            remit_rows = (
+                s.query(Remittance)
+                .filter(Remittance.claim_id.in_(claim_ids))
+                .all()
+            )
+
+        if not claim_rows and not remit_rows:
+            raise HTTPException(
+                status_code=404,
+                detail=f"Payer {payer_id!r} not found",
+            )
+
+        billed_total = sum(float(c.charge_amount or 0) for c in claim_rows)
+        received_total = sum(float(r.total_paid or 0) for r in remit_rows)
+        denied = sum(
+            1 for c in claim_rows if c.state == ClaimState.DENIED
+        )
+        claim_count = len(claim_rows)
+        denial_rate = (denied / claim_count) if claim_count else 0.0
+
+        provider_counts: dict[str, int] = {}
+        for c in claim_rows:
+            npi = c.provider_npi
+            if not npi:
+                continue
+            provider_counts[npi] = provider_counts.get(npi, 0) + 1
+        top_providers = [
+            {"npi": npi, "count": count}
+            for npi, count in sorted(
+                provider_counts.items(), key=lambda kv: -kv[1]
+            )[:5]
+        ]
+
+        # Best-effort payer display name from the first claim's raw
+        # payer object (NM1*PR name element, e.g. "COHCPF"). Falls
+        # back to the id when no parsed envelope is available.
+        payer_name = payer_id
+        for c in claim_rows:
+            raw = c.raw_json or {}
+            p = raw.get("payer") if isinstance(raw, dict) else None
+            if isinstance(p, dict) and p.get("name"):
+                payer_name = p["name"]
+                break
+
+    payload = {
+        "payer_id": payer_id,
+        "name": payer_name,
+        "claim_count": claim_count,
+        "billed_total": billed_total,
+        "received_total": received_total,
+        "denial_rate": denial_rate,
+        "top_providers": top_providers,
+    }
+    _summary_cache[payer_id] = (now, payload)
+    return payload
+
+
 @app.post("/api/admin/reload-config")
 def reload_config():
     """Re-read ``config/payers.yaml`` and revalidate. Returns counts."""

backend/src/cyclone/store.py

@@ -1668,7 +1668,16 @@ class CycloneStore:
             return list(by_npi.values())
 
     def recent_activity(self, *, limit: int = 200) -> list[dict]:
-        """Return recent activity events from the DB, newest first."""
+        """Return recent activity events from the DB, newest first.
+
+        SP21 Task 2.5: each row also carries ``claimId`` and
+        ``remittanceId`` (read from the ORM columns) so the Dashboard's
+        Recent-activity card can route clicks to the right entity
+        drawer via ``src/lib/event-routing.ts``. Both are nullable
+        strings; the wire shape uses camelCase keys to match the
+        existing ``npi`` / ``amount`` fields and the frontend
+        ``Activity`` interface.
+        """
         with db.SessionLocal()() as s:
             rows = (
                 s.query(ActivityEvent)
@@ -1684,6 +1693,8 @@ class CycloneStore:
                     "timestamp": r.ts.isoformat().replace("+00:00", "Z"),
                     "npi": (r.payload_json or {}).get("npi"),
                     "amount": (r.payload_json or {}).get("amount"),
+                    "claimId": r.claim_id,
+                    "remittanceId": r.remittance_id,
                 }
                 for r in rows
             ]

backend/tests/test_api.py

@@ -160,3 +160,51 @@ def test_cors_headers_present(client: TestClient):
     )
     assert resp.headers.get("access-control-allow-origin") == "http://localhost:5173"
     assert "POST" in resp.headers.get("access-control-allow-methods", "").upper()
+
+
+def test_cors_headers_present_for_loopback_ip(client: TestClient):
+    # ``http://127.0.0.1:5173`` is a distinct origin from
+    # ``http://localhost:5173`` per the CORS spec, even though both resolve
+    # to the same Vite dev server. Both must be allow-listed or tabs opened
+    # via the IP form silently break.
+    resp = client.options(
+        "/api/parse-837",
+        headers={
+            "Origin": "http://127.0.0.1:5173",
+            "Access-Control-Request-Method": "POST",
+            "Access-Control-Request-Headers": "content-type",
+        },
+    )
+    assert resp.headers.get("access-control-allow-origin") == "http://127.0.0.1:5173"
+
+
+def test_cors_extra_origins_via_env(client: TestClient, monkeypatch):
+    # LAN / staging hosts opt in via CYCLONE_ALLOWED_ORIGINS. The env var
+    # is a comma-separated list; the middleware must reflect each entry.
+    # The allow-list is built at module import, so we re-execute the
+    # module under the env var and build a TestClient against the
+    # reloaded app.
+    monkeypatch.setenv(
+        "CYCLONE_ALLOWED_ORIGINS", "http://192.168.1.42:5173,https://staging.example.com"
+    )
+    import importlib
+    from cyclone import api as api_module
+    from fastapi.testclient import TestClient as _TC
+    importlib.reload(api_module)
+    try:
+        with _TC(api_module.app) as tc:
+            for origin in ("http://192.168.1.42:5173", "https://staging.example.com"):
+                resp = tc.options(
+                    "/api/parse-837",
+                    headers={
+                        "Origin": origin,
+                        "Access-Control-Request-Method": "POST",
+                        "Access-Control-Request-Headers": "content-type",
+                    },
+                )
+                assert resp.headers.get("access-control-allow-origin") == origin
+    finally:
+        monkeypatch.delenv("CYCLONE_ALLOWED_ORIGINS", raising=False)
+        # Reload once more so the module-level allow-list returns to its
+        # default for any test that imports `cyclone.api` after this one.
+        importlib.reload(api_module)

backend/tests/test_payer_summary.py

@@ -0,0 +1,106 @@
+"""Tests for GET /api/payers/{payer_id}/summary (SP21 Task 1.5).
+
+The endpoint is the payer-level aggregate that the drill-down UI's
+"Payer → Claims" panel hangs off. It returns billed/received totals,
+denial rate, and the top 5 NPIs by claim volume for one payer_id,
+cached in-process for 60s.
+
+The minimal 837P fixture ships one CLM with ``payer_id="SKCO0"``,
+charge_amount=100.00; the minimal 835 carries one CLP for the same
+claim with total_paid=85.00. So ``/api/payers/SKCO0/summary`` returns
+``claim_count >= 1`` after both files are ingested.
+
+Note: the spec calls this ``payer_id`` (the X12 NM1*PR*PI qualifier,
+e.g. ``SKCO0``). It is NOT the configured payer name from
+``config/payers.yaml``. The filter key in the store layer is
+``Claim.payer_id`` — not the ``payer=`` substring filter used by
+``/api/claims?payer=...``.
+"""
+from __future__ import annotations
+
+from pathlib import Path
+
+import pytest
+from fastapi.testclient import TestClient
+
+from cyclone import api as api_mod
+from cyclone.api import app
+
+FIXTURE_837 = Path(__file__).parent / "fixtures" / "minimal_837p.txt"
+FIXTURE_835 = Path(__file__).parent / "fixtures" / "minimal_835.txt"
+
+
+@pytest.fixture(autouse=True)
+def _clear_summary_cache():
+    """Wipe the in-process payer-summary cache between tests.
+
+    conftest resets the DB per test but the cache is module-level
+    state on ``cyclone.api``. Without this clear, a stale payload
+    from a previous test's seed would leak into a later test's first
+    call — masking recompute behavior. The 60s TTL is the only
+    invalidation story today (see api.py docstring on the endpoint).
+    """
+    api_mod._clear_summary_cache()
+    yield
+    api_mod._clear_summary_cache()
+
+
+@pytest.fixture
+def client() -> TestClient:
+    return TestClient(app)
+
+
+@pytest.fixture
+def seeded_db(client: TestClient):
+    """Ingest one minimal 837P + one minimal 835.
+
+    Both fixtures carry ``payer_id="SKCO0"`` so the summary endpoint
+    has something to aggregate. ``client`` is yielded back so the
+    test can hit the API on the same TestClient that ingested the
+    fixtures (parses share the per-test SQLite from conftest).
+    """
+    text_837 = FIXTURE_837.read_text()
+    text_835 = FIXTURE_835.read_text()
+    r837 = client.post(
+        "/api/parse-837",
+        files={"file": ("x.txt", text_837, "text/plain")},
+        headers={"Accept": "application/json"},
+    )
+    assert r837.status_code == 200, r837.text
+    r835 = client.post(
+        "/api/parse-835",
+        files={"file": ("era.txt", text_835, "text/plain")},
+        headers={"Accept": "application/json"},
+    )
+    assert r835.status_code == 200, r835.text
+    return client
+
+
+def test_payer_summary_happy_path(seeded_db: TestClient):
+    """Seeded db has at least one claim for SKCO0 → 200 with the spec shape."""
+    resp = seeded_db.get("/api/payers/SKCO0/summary")
+    assert resp.status_code == 200, resp.text
+    data = resp.json()
+    assert data["payer_id"] == "SKCO0"
+    assert "claim_count" in data
+    assert "billed_total" in data
+    assert "received_total" in data
+    assert "denial_rate" in data
+    assert data["claim_count"] >= 1
+    # denial_rate must be a float in [0, 1] (0/1 claim → 0.0).
+    assert isinstance(data["denial_rate"], (int, float))
+    assert 0.0 <= data["denial_rate"] <= 1.0
+
+
+def test_payer_summary_unknown_payer_returns_404(client: TestClient):
+    resp = client.get("/api/payers/DOES_NOT_EXIST/summary")
+    assert resp.status_code == 404
+
+
+def test_payer_summary_caches_then_invalidates(seeded_db: TestClient):
+    """Two back-to-back calls return identical payloads (in-process cache)."""
+    resp1 = seeded_db.get("/api/payers/SKCO0/summary")
+    resp2 = seeded_db.get("/api/payers/SKCO0/summary")
+    assert resp1.status_code == 200
+    assert resp2.status_code == 200
+    assert resp1.json() == resp2.json()

backend/tests/test_provider_extended_response.py

@@ -0,0 +1,177 @@
+"""Tests for the extended GET /api/config/providers/{npi} (SP21 Task 1.6).
+
+The endpoint gains two new top-level arrays for the drill-down panel:
+``recent_claims`` (top 10 by submission date desc) and ``recent_activity``
+(top 10 by ``ts`` desc, joined to claims by ``claim_id`` because
+``ActivityEvent`` has no direct ``provider_npi`` column).
+
+Existing SP9 fields (``label``, ``legal_name``, ``tax_id``,
+``address_line1``, ``city``, ``state``, ``zip``, etc.) must remain
+present — the new arrays are additive only.
+
+The fixtures in ``fixtures/minimal_837p.txt`` and ``fixtures/minimal_835.txt``
+pair up to a single claim with ``provider_npi='1993999998'``. That NPI is
+NOT in the seeded provider set (Montrose/Delta/Salida → 1881068062/1851446637/
+1467507269). For the tests we hit the seeded Montrose NPI, which is the
+canonical SP9 fixture NPI. The arrays come back as empty lists — the
+contract under test is the *shape* (array, ≤10) and the *backwards compat*
+of the existing fields; the data-path itself is exercised by the existing
+ingestion path that backs ``/api/claims``.
+"""
+from __future__ import annotations
+
+from datetime import datetime, timezone
+from pathlib import Path
+
+import pytest
+from fastapi.testclient import TestClient
+
+from cyclone.api import app
+from cyclone.providers import Provider
+from cyclone.store import store
+
+FIXTURE_837 = Path(__file__).parent / "fixtures" / "minimal_837p.txt"
+FIXTURE_835 = Path(__file__).parent / "fixtures" / "minimal_835.txt"
+
+# Montrose — one of the three providers that `ensure_clearhouse_seeded()`
+# writes into the providers table. Using a seeded NPI means the endpoint
+# won't 404; the seeded claims (provider_npi='1993999998') won't appear
+# under this NPI, so recent_claims/activity are expected empty lists.
+MONTROSE_NPI = "1881068062"
+
+# NPI the minimal 837P fixture bills under. NOT in the default seed —
+# registering it before ingest is required to pass R204 (NPI must exist
+# in the providers table).
+TEST_837_NPI = "1993999998"
+
+
+@pytest.fixture
+def client() -> TestClient:
+    return TestClient(app)
+
+
+@pytest.fixture
+def seeded_db(client: TestClient):
+    """Seed the clearhouse + ingest the minimal 837P/835 fixtures.
+
+    Mirrors the Task 1.5 ``seeded_db`` pattern: seed → ingest → hand the
+    client back so the test hits the same TestClient.
+
+    The 837 fixture bills under ``TEST_837_NPI``; without first registering
+    that provider the parser's R204 rule rejects the claim with HTTP 422.
+    """
+    store.ensure_clearhouse_seeded()
+    test_provider = Provider(
+        npi=TEST_837_NPI,
+        label="Test Provider",
+        legal_name="Test Provider Inc",
+        tax_id="123456789",
+        taxonomy_code="207R00000X",
+        address_line1="123 Test St",
+        city="Denver",
+        state="CO",
+        zip="80202",
+        created_at=datetime.now(timezone.utc),
+        updated_at=datetime.now(timezone.utc),
+    )
+    store.upsert_provider(test_provider)
+    text_837 = FIXTURE_837.read_text()
+    text_835 = FIXTURE_835.read_text()
+    r837 = client.post(
+        "/api/parse-837",
+        files={"file": ("x.txt", text_837, "text/plain")},
+        headers={"Accept": "application/json"},
+    )
+    assert r837.status_code == 200, r837.text
+    r835 = client.post(
+        "/api/parse-835",
+        files={"file": ("era.txt", text_835, "text/plain")},
+        headers={"Accept": "application/json"},
+    )
+    assert r835.status_code == 200, r835.text
+    return client
+
+
+def test_provider_detail_includes_recent_claims(seeded_db: TestClient):
+    """The extended response gains a recent_claims array (top 10)."""
+    resp = seeded_db.get(f"/api/config/providers/{MONTROSE_NPI}")
+    assert resp.status_code == 200, resp.text
+    data = resp.json()
+    assert "recent_claims" in data
+    assert isinstance(data["recent_claims"], list)
+    assert len(data["recent_claims"]) <= 10
+
+
+def test_provider_detail_includes_recent_activity(seeded_db: TestClient):
+    """The extended response gains a recent_activity array (top 10)."""
+    resp = seeded_db.get(f"/api/config/providers/{MONTROSE_NPI}")
+    assert resp.status_code == 200, resp.text
+    data = resp.json()
+    assert "recent_activity" in data
+    assert isinstance(data["recent_activity"], list)
+    assert len(data["recent_activity"]) <= 10
+
+
+def test_provider_detail_backwards_compat(seeded_db: TestClient):
+    """All SP9 fields still present; new arrays don't break the contract.
+
+    The Provider Pydantic model (backend/src/cyclone/providers.py)
+    serializes snake_case fields — that's what the wire carries. The
+    TS ``Provider`` interface in ``src/types/index.ts`` is the
+    in-memory sample shape and intentionally diverges; the contract
+    being verified here is the API's actual payload.
+    """
+    resp = seeded_db.get(f"/api/config/providers/{MONTROSE_NPI}")
+    assert resp.status_code == 200, resp.text
+    data = resp.json()
+    for key in (
+        "npi",
+        "label",
+        "legal_name",
+        "tax_id",
+        "taxonomy_code",
+        "address_line1",
+        "city",
+        "state",
+        "zip",
+        "is_active",
+    ):
+        assert key in data, f"missing field {key}"
+
+
+def test_provider_detail_includes_orphan_remit_received(seeded_db: TestClient):
+    """Regression: the ``remit_received`` ActivityEvent is recorded at 835
+    ingest with ``claim_id=None`` (``store.add`` lines 999-1003) — the
+    remittance hasn't been matched to a claim yet. The original
+    ``ActivityEvent.claim_id IN (claim_ids)`` filter misses it because
+    the orphan's claim_id is NULL.
+
+    Once reconciliation (auto or manual) populates
+    ``Remittance.claim_id``, the activity filter must surface the event
+    via the ``Remittance.claim_id IN (claim_ids)`` branch of the OR.
+    Without that branch, a provider's activity feed appears to freeze
+    the moment an 835 lands — the most common activity, invisible.
+
+    Setup: ingest 837+835 for ``TEST_837_NPI`` (claim CLM001 + remit
+    CLM001), then manually match them so ``Remittance.claim_id`` is
+    populated. The bug presents as: only ``claim_submitted`` and
+    ``manual_match`` appear (no ``remit_received``). The fix surfaces
+    all three.
+    """
+    # Force the match — simulates the post-reconciliation state that
+    # populate Remittance.claim_id without depending on auto-reconcile
+    # heuristics (which don't match this minimal fixture).
+    match_resp = seeded_db.post(
+        "/api/reconciliation/match",
+        json={"claim_id": "CLM001", "remit_id": "CLM001"},
+    )
+    assert match_resp.status_code == 200, match_resp.text
+
+    resp = seeded_db.get(f"/api/config/providers/{TEST_837_NPI}")
+    assert resp.status_code == 200, resp.text
+    data = resp.json()
+    kinds = {event["kind"] for event in data["recent_activity"]}
+    assert "remit_received" in kinds, (
+        f"expected remit_received in recent_activity (orphan remits "
+        f"must surface via the Remittance join), got kinds={sorted(kinds)}"
+    )

src/App.tsx

@@ -1,6 +1,7 @@
 import { Route, Routes } from "react-router-dom";
 import { Toaster } from "sonner";
 import { Layout } from "@/components/Layout";
+import { DrillStackProvider } from "@/components/drill/DrillStackProvider";
 import { Dashboard } from "@/pages/Dashboard";
 import { Claims } from "@/pages/Claims";
 import { Remittances } from "@/pages/Remittances";
@@ -24,7 +25,7 @@ function NotFound() {
 
 export default function App() {
   return (
-    <>
+    <DrillStackProvider>
       <Routes>
         <Route element={<Layout />}>
           <Route index element={<Dashboard />} />
@@ -52,6 +53,6 @@ export default function App() {
           },
         }}
       />
-    </>
+    </DrillStackProvider>
   );
 }

src/components/ActivityFeed.test.tsx

@@ -1,11 +1,15 @@
 // @vitest-environment happy-dom
 (globalThis as { IS_REACT_ACT_ENVIRONMENT?: boolean }).IS_REACT_ACT_ENVIRONMENT = true;
 
-import { describe, expect, it } from "vitest";
-import { render, screen } from "@testing-library/react";
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { cleanup, fireEvent, render, screen } from "@testing-library/react";
 import { ActivityFeed } from "./ActivityFeed";
 import type { Activity } from "@/types";
 
+// happy-dom keeps `document.body` between tests; without cleanup,
+// `screen.getByRole("button")` finds buttons from earlier renders.
+afterEach(() => cleanup());
+
 const baseActivity: Activity = {
   id: "a-1",
   kind: "claim_submitted",
@@ -47,4 +51,99 @@ describe("ActivityFeed", () => {
     expect(() => render(<ActivityFeed items={[unknown]} />)).not.toThrow();
     expect(screen.getByText("future_kind event arrived")).toBeTruthy();
   });
+
+  // -------------------------------------------------------------------
+  // SP21 Task 2.5: optional `onItemClick` prop makes each row a
+  // drillable target. Default behavior (no handler) must stay unchanged.
+  // -------------------------------------------------------------------
+
+  it("does not attach row-level click attrs when onItemClick is omitted", () => {
+    render(<ActivityFeed items={[baseActivity]} />);
+    const li = screen.getByRole("listitem");
+    expect(li.getAttribute("role")).not.toBe("button");
+    expect(li.getAttribute("tabindex")).toBeNull();
+    expect(li.classList.contains("drillable")).toBe(false);
+  });
+
+  it("attaches role/tabIndex/drillable class when onItemClick is provided", () => {
+    render(
+      <ActivityFeed
+        items={[baseActivity]}
+        onItemClick={() => {}}
+      />,
+    );
+    const li = screen.getByRole("button", { name: /View claim submitted/ });
+    expect(li.tagName).toBe("LI");
+    expect(li.getAttribute("tabindex")).toBe("0");
+    expect(li.classList.contains("drillable")).toBe(true);
+  });
+
+  it("calls onItemClick with the event on click", () => {
+    const onItemClick = vi.fn();
+    render(
+      <ActivityFeed
+        items={[baseActivity]}
+        onItemClick={onItemClick}
+      />,
+    );
+    const li = screen.getByRole("button");
+    fireEvent.click(li);
+    expect(onItemClick).toHaveBeenCalledTimes(1);
+    expect(onItemClick).toHaveBeenCalledWith(baseActivity);
+  });
+
+  it("calls onItemClick on Enter keydown", () => {
+    const onItemClick = vi.fn();
+    render(
+      <ActivityFeed
+        items={[baseActivity]}
+        onItemClick={onItemClick}
+      />,
+    );
+    const li = screen.getByRole("button");
+    fireEvent.keyDown(li, { key: "Enter" });
+    expect(onItemClick).toHaveBeenCalledTimes(1);
+    expect(onItemClick).toHaveBeenCalledWith(baseActivity);
+  });
+
+  it("calls onItemClick on Space keydown", () => {
+    const onItemClick = vi.fn();
+    render(
+      <ActivityFeed
+        items={[baseActivity]}
+        onItemClick={onItemClick}
+      />,
+    );
+    fireEvent.keyDown(screen.getByRole("button"), { key: " " });
+    expect(onItemClick).toHaveBeenCalledTimes(1);
+  });
+
+  it("does not call onItemClick for unrelated keys", () => {
+    const onItemClick = vi.fn();
+    render(
+      <ActivityFeed
+        items={[baseActivity]}
+        onItemClick={onItemClick}
+      />,
+    );
+    fireEvent.keyDown(screen.getByRole("button"), { key: "a" });
+    expect(onItemClick).not.toHaveBeenCalled();
+  });
+
+  // Regression for the Task 2.4 event-bubbling pattern: clicks on a
+  // drillable row must not bubble to a parent row click. Without
+  // stopPropagation a Dashboard parent handler could fire alongside
+  // the row click and corrupt history.
+  it("stops click propagation so a parent row handler does not also fire", () => {
+    const onItemClick = vi.fn();
+    const parentClick = vi.fn();
+    render(
+      <ul onClick={parentClick}>
+        <ActivityFeed items={[baseActivity]} onItemClick={onItemClick} />
+      </ul>,
+    );
+    fireEvent.click(screen.getByRole("button"));
+    expect(onItemClick).toHaveBeenCalledTimes(1);
+    expect(parentClick).not.toHaveBeenCalled();
+  });
 });

src/components/ActivityFeed.tsx

@@ -1,3 +1,4 @@
+import type { KeyboardEvent, MouseEvent } from "react";
 import {
   Banknote,
   CheckCircle2,
@@ -63,9 +64,22 @@ const FALLBACK_KIND: { icon: LucideIcon; tone: string; tint: string } = {
 export function ActivityFeed({
   items,
   emptyMessage = "No activity yet.",
+  onItemClick,
 }: {
   items: Activity[];
   emptyMessage?: string;
+  /**
+   * Optional click handler for SP21 Universal Drill-Down (Task 2.5).
+   * When provided, each row becomes a clickable target: the row's
+   * outer `<li>` gets `role="button"`, `tabIndex`, the `drillable`
+   * hover affordance (chevron + tint), and an Enter/Space keybinding.
+   *
+   * `e.stopPropagation()` is called before invoking the handler so the
+   * click doesn't bubble to a hypothetical parent row click — same
+   * fix that landed on `DrillableCell` in Task 2.4. When omitted, the
+   * feed renders exactly as before (no extra DOM, no extra attrs).
+   */
+  onItemClick?: (event: Activity) => void;
 }) {
   if (items.length === 0) {
     return (
@@ -79,11 +93,36 @@ export function ActivityFeed({
       {items.map((a) => {
         const cfg = kindConfig[a.kind] ?? FALLBACK_KIND;
         const Icon = cfg.icon;
+        // SP21 Task 2.5: when a click handler is wired, the row
+        // becomes a keyboard-focusable button-like element with the
+        // drillable hover affordance. We attach the handler to the
+        // <li> directly (matching the Dashboard's existing patterns
+        // for "Top providers" / "Recent denials" rows) so the click
+        // target covers the full row width including padding.
+        const rowProps = onItemClick
+          ? {
+              role: "button" as const,
+              tabIndex: 0,
+              "aria-label": `View ${a.kind.replace(/_/g, " ")}: ${a.message}`,
+              className:
+                "drillable flex items-start gap-3 py-3 first:pt-0 last:pb-0 rounded-sm focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-1",
+              onClick: (e: MouseEvent<HTMLLIElement>) => {
+                e.stopPropagation();
+                onItemClick(a);
+              },
+              onKeyDown: (e: KeyboardEvent<HTMLLIElement>) => {
+                if (e.key === "Enter" || e.key === " ") {
+                  e.preventDefault();
+                  e.stopPropagation();
+                  onItemClick(a);
+                }
+              },
+            }
+          : {
+              className: "flex items-start gap-3 py-3 first:pt-0 last:pb-0",
+            };
         return (
-          <li
-            key={a.id}
-            className="flex items-start gap-3 py-3 first:pt-0 last:pb-0"
-          >
+          <li key={a.id} {...rowProps}>
             <div
               className={cn(
                 "mt-0.5 h-7 w-7 shrink-0 rounded-md ring-1 ring-inset ring-border/40 flex items-center justify-center",

src/components/BatchDiffView.tsx

@@ -1,4 +1,10 @@
-import { Plus, Minus, Equal, ArrowRight, type LucideIcon } from "lucide-react";
+import {
+  ArrowRight,
+  Equal,
+  Minus,
+  Plus,
+  type LucideIcon,
+} from "lucide-react";
 import { Badge } from "@/components/ui/badge";
 import { Skeleton } from "@/components/ui/skeleton";
 import {
@@ -9,19 +15,20 @@ import {
   TableHeader,
   TableRow,
 } from "@/components/ui/table";
-import { KpiCard } from "@/components/KpiCard";
 import { fmt } from "@/lib/format";
 import { cn } from "@/lib/utils";
 import type {
+  BatchClaimDiffSummary,
   BatchDiff,
   BatchDiffChangedRow,
   BatchDiffSideMeta,
   BatchDiffSummary,
-  BatchClaimDiffSummary,
 } from "@/types";
 
 // ---------------------------------------------------------------------------
-// Side meta header — small panel identifying which batch is on the left / right.
+// Side meta header — small panel identifying which batch is on the
+// left / right. Paper-toned to sit inside the cream "paper plane" of
+// the BatchDiff page. data-testid pinned by BatchDiff.test.tsx.
 // ---------------------------------------------------------------------------
 
 function SideMeta({
@@ -39,10 +46,19 @@ function SideMeta({
       : "text-amber-300 border-amber-400/30 bg-amber-400/10";
   return (
     <div
-      className="surface rounded-xl p-4 flex flex-col gap-2"
+      className="rounded-xl p-4 flex flex-col gap-2 border"
       data-testid={`batch-diff-side-${label.toLowerCase()}`}
+      style={{
+        backgroundColor: "hsl(36 22% 98%)",
+        borderColor: "hsl(30 14% 14% / 0.10)",
+        boxShadow:
+          "inset 0 1px 0 0 hsl(0 0% 100% / 0.45), 0 1px 0 0 hsl(30 14% 22% / 0.06)",
+      }}
     >
-      <div className="text-[10.5px] font-semibold uppercase tracking-[0.18em] text-muted-foreground">
+      <div
+        className="text-[10.5px] font-semibold uppercase tracking-[0.18em]"
+        style={{ color: "hsl(var(--surface-ink-3))" }}
+      >
         {label}
       </div>
       <div className="flex items-center gap-2">
@@ -54,12 +70,23 @@ function SideMeta({
         >
           {side.kind}
         </span>
-        <span className="display num text-[13px]">{side.id}</span>
+        <span
+          className="display num text-[13px]"
+          style={{ color: "hsl(var(--surface-ink))" }}
+        >
+          {side.id}
+        </span>
       </div>
-      <div className="font-mono text-[12px] text-muted-foreground truncate">
+      <div
+        className="font-mono text-[12px] truncate"
+        style={{ color: "hsl(var(--surface-ink-2))" }}
+      >
         {side.inputFilename}
       </div>
-      <div className="flex items-center justify-between text-xs text-muted-foreground">
+      <div
+        className="flex items-center justify-between text-xs"
+        style={{ color: "hsl(var(--surface-ink-3))" }}
+      >
         <span>Parsed {side.parsedAt ? fmt.dateShort(side.parsedAt) : "—"}</span>
         <span className="font-mono num">
           {fmt.num(side.claimCount)} claim{side.claimCount === 1 ? "" : "s"}
@@ -70,40 +97,125 @@ function SideMeta({
 }
 
 // ---------------------------------------------------------------------------
-// Summary cards — the four-count tile row.
+// Summary cards — the four-count tile row. Paper-toned via
+// DiffKpiTile so the counts sit naturally on the cream paper plane.
 // ---------------------------------------------------------------------------
 
 function SummaryCards({ summary }: { summary: BatchDiffSummary }) {
   return (
-    <div className="grid grid-cols-2 md:grid-cols-4 gap-3" data-testid="batch-diff-summary">
-      <KpiCard
+    <div
+      className="grid grid-cols-2 md:grid-cols-4 gap-3"
+      data-testid="batch-diff-summary"
+    >
+      <DiffKpiTile
         label="Added in B"
         value={fmt.num(summary.addedCount)}
         icon={Plus}
         hint="In B, not in A"
+        tone="success"
       />
-      <KpiCard
+      <DiffKpiTile
         label="Removed from A"
         value={fmt.num(summary.removedCount)}
         icon={Minus}
         hint="In A, not in B"
+        tone="destructive"
       />
-      <KpiCard
+      <DiffKpiTile
         label="Changed"
         value={fmt.num(summary.changedCount)}
         icon={Equal}
         hint="Deltas in either side"
+        tone="amber"
       />
-      <KpiCard
+      <DiffKpiTile
         label="Unchanged"
         value={fmt.num(summary.unchangedCount)}
         icon={Equal}
         hint="Identical across A & B"
+        tone="ink"
       />
     </div>
   );
 }
 
+// ---------------------------------------------------------------------------
+// DiffKpiTile — paper-toned metric tile for the diff summary row.
+// Mirrors AckKpiTile / BatchesKpiTile from the other hybrid pages.
+// ---------------------------------------------------------------------------
+
+function DiffKpiTile({
+  label,
+  value,
+  icon: Icon,
+  hint,
+  tone,
+}: {
+  label: string;
+  value: string;
+  icon: LucideIcon;
+  hint: string;
+  tone: "success" | "destructive" | "amber" | "ink";
+}) {
+  const accentMap = {
+    success: "hsl(152 64% 38%)",
+    destructive: "hsl(358 70% 42%)",
+    amber: "hsl(36 92% 50%)",
+    ink: "hsl(var(--surface-ink))",
+  } as const;
+  const tintMap = {
+    success: "hsl(152 50% 88%)",
+    destructive: "hsl(358 70% 92%)",
+    amber: "hsl(36 82% 92%)",
+    ink: "hsl(36 22% 90%)",
+  } as const;
+  const accent = accentMap[tone];
+  const tint = tintMap[tone];
+  return (
+    <div
+      className="relative rounded-xl p-4 overflow-hidden border"
+      title={hint}
+      style={{
+        backgroundColor: "hsl(var(--surface))",
+        boxShadow:
+          "inset 0 1px 0 0 hsl(0 0% 100% / 0.45), 0 1px 0 0 hsl(30 14% 22% / 0.06), inset 3px 0 0 0 hsl(0 0% 100% / 0.4)",
+        borderColor: "hsl(30 14% 14% / 0.10)",
+      }}
+    >
+      <div
+        aria-hidden
+        className="absolute left-0 top-4 bottom-4 w-[3px] rounded-r-sm"
+        style={{ backgroundColor: accent, opacity: 0.85 }}
+      />
+      <div className="flex items-center justify-between mb-2">
+        <div
+          className="mono text-[10px] uppercase tracking-[0.18em] font-semibold"
+          style={{ color: "hsl(var(--surface-ink-3))" }}
+        >
+          {label}
+        </div>
+        <div
+          className="h-5 w-5 rounded-md flex items-center justify-center"
+          style={{ backgroundColor: tint, color: accent }}
+        >
+          <Icon className="h-3 w-3" strokeWidth={1.75} />
+        </div>
+      </div>
+      <div
+        className="display tabular-nums tracking-[-0.04em]"
+        style={{
+          color: "hsl(var(--surface-ink))",
+          fontSize: "clamp(26px, 2.8vw, 36px)",
+          lineHeight: 1,
+          fontWeight: 400,
+        }}
+      >
+        {value}
+      </div>
+    </div>
+  );
+}
+
 // ---------------------------------------------------------------------------
 // Row indicator — `+` / `-` / `~` gutter on the left of every row.
 // ---------------------------------------------------------------------------
@@ -152,7 +264,10 @@ function RowIndicator({
 
 function ClaimIdCell({ id }: { id: string }) {
   return (
-    <span className="font-mono text-[12px] tracking-tight" data-testid="diff-claim-id">
+    <span
+      className="font-mono text-[12px] tracking-tight"
+      data-testid="diff-claim-id"
+    >
       {id}
     </span>
   );
@@ -160,14 +275,31 @@ function ClaimIdCell({ id }: { id: string }) {
 
 function PatientCell({ name }: { name: string }) {
   if (!name) {
-    return <span className="text-muted-foreground/60 text-[12px]">—</span>;
+    return (
+      <span
+        className="text-[12px]"
+        style={{ color: "hsl(var(--surface-ink-3))" }}
+      >
+        —
+      </span>
+    );
   }
-  return <span className="text-[13px]">{name}</span>;
+  return (
+    <span
+      className="text-[13px]"
+      style={{ color: "hsl(var(--surface-ink))" }}
+    >
+      {name}
+    </span>
+  );
 }
 
 function ChargeCell({ value }: { value: number }) {
   return (
-    <span className="display num text-[13px] tabular-nums">
+    <span
+      className="display num text-[13px] tabular-nums"
+      style={{ color: "hsl(var(--surface-ink))" }}
+    >
       {fmt.usdPrecise(value)}
     </span>
   );
@@ -175,19 +307,44 @@ function ChargeCell({ value }: { value: number }) {
 
 function DateCell({ value }: { value: string | null }) {
   if (!value) {
-    return <span className="text-muted-foreground/60 text-[12px]">—</span>;
+    return (
+      <span
+        className="text-[12px]"
+        style={{ color: "hsl(var(--surface-ink-3))" }}
+      >
+        —
+      </span>
+    );
   }
-  return <span className="num text-[12.5px]">{value}</span>;
+  return (
+    <span
+      className="num text-[12.5px]"
+      style={{ color: "hsl(var(--surface-ink-2))" }}
+    >
+      {value}
+    </span>
+  );
 }
 
 function StatusCell({ value }: { value: string }) {
   if (!value) {
-    return <span className="text-muted-foreground/60 text-[12px]">—</span>;
+    return (
+      <span
+        className="text-[12px]"
+        style={{ color: "hsl(var(--surface-ink-3))" }}
+      >
+        —
+      </span>
+    );
   }
   return (
     <Badge
       variant="outline"
       className="font-mono uppercase tracking-wider text-[10px]"
+      style={{
+        color: "hsl(var(--surface-ink))",
+        borderColor: "hsl(30 14% 14% / 0.20)",
+      }}
     >
       {value}
     </Badge>
@@ -196,17 +353,28 @@ function StatusCell({ value }: { value: string }) {
 
 function CptCell({ codes }: { codes: string[] }) {
   if (!codes || codes.length === 0) {
-    return <span className="text-muted-foreground/60 text-[12px]">—</span>;
+    return (
+      <span
+        className="text-[12px]"
+        style={{ color: "hsl(var(--surface-ink-3))" }}
+      >
+        —
+      </span>
+    );
   }
   return (
-    <span className="font-mono text-[11.5px] tracking-tight">
+    <span
+      className="font-mono text-[11.5px] tracking-tight"
+      style={{ color: "hsl(var(--surface-ink-2))" }}
+    >
       {codes.join(", ")}
     </span>
   );
 }
 
 // ---------------------------------------------------------------------------
-// Section tables — one per bucket (added / removed / changed).
+// Section tables — one per bucket (added / removed / changed). Uses
+// `tone="paper"` so the table chrome matches the cream paper plane.
 // ---------------------------------------------------------------------------
 
 type Side = "a" | "b";
@@ -386,25 +554,53 @@ function SectionTable({
     <section className="space-y-3" data-testid={testid}>
       <header className="flex items-baseline justify-between">
         <div>
-          <div className="text-[10.5px] font-semibold uppercase tracking-[0.18em] text-muted-foreground mb-0.5">
+          <div
+            className="text-[10.5px] font-semibold uppercase tracking-[0.18em] mb-0.5"
+            style={{ color: "hsl(var(--surface-ink-3))" }}
+          >
             {eyebrow}
           </div>
-          <h2 className="text-[15px] font-semibold tracking-tight">{title}</h2>
+          <h3
+            className="display leading-[0.98] tracking-[-0.03em]"
+            style={{
+              color: "hsl(var(--surface-ink))",
+              fontSize: "clamp(20px, 2.2vw, 26px)",
+              fontWeight: 400,
+            }}
+          >
+            {title}
+          </h3>
         </div>
-        <span className="font-mono num text-[12.5px] text-muted-foreground">
+        <span
+          className="font-mono num text-[12.5px]"
+          style={{ color: "hsl(var(--surface-ink-3))" }}
+        >
           {fmt.num(count)}
         </span>
       </header>
       {count === 0 ? (
         <div
-          className="surface rounded-xl border border-dashed border-border/60 p-6 text-center text-[12.5px] text-muted-foreground"
+          className="rounded-xl border p-6 text-center text-[12.5px]"
           data-testid={`${testid}-empty`}
+          style={{
+            borderColor: "hsl(30 14% 14% / 0.16)",
+            borderStyle: "dashed",
+            backgroundColor: "hsl(36 22% 96%)",
+            color: "hsl(var(--surface-ink-3))",
+          }}
         >
           {emptyMessage}
         </div>
       ) : (
-        <div className="surface rounded-xl overflow-hidden">
-          <Table>
+        <div
+          className="rounded-xl border overflow-hidden"
+          style={{
+            borderColor: "hsl(30 14% 14% / 0.10)",
+            backgroundColor: "hsl(36 22% 98%)",
+            boxShadow: "inset 0 1px 0 0 hsl(0 0% 100% / 0.5)",
+          }}
+        >
+          <Table tone="paper">
             <TableHeader>
               <TableRow>
                 <TableHead className="w-10" aria-label="Diff indicator" />
@@ -425,7 +621,8 @@ function SectionTable({
 }
 
 // ---------------------------------------------------------------------------
-// Skeleton — used by the page while the diff is loading.
+// Skeleton — used by the page while the diff is loading. Paper-toned
+// (cream blocks) to match the paper plane chrome.
 // ---------------------------------------------------------------------------
 
 export function BatchDiffViewSkeleton() {
@@ -462,11 +659,24 @@ export function BatchDiffEmpty({ data }: { data: BatchDiff }) {
         <SideMeta side={data.b} label="B (right)" />
       </div>
       <SummaryCards summary={data.summary} />
-      <div className="surface rounded-xl border border-dashed border-border/60 p-10 text-center">
-        <div className="text-[10.5px] font-semibold uppercase tracking-[0.18em] text-muted-foreground mb-1.5">
+      <div
+        className="rounded-xl border p-10 text-center"
+        style={{
+          borderColor: "hsl(30 14% 14% / 0.16)",
+          borderStyle: "dashed",
+          backgroundColor: "hsl(36 22% 96%)",
+        }}
+      >
+        <div
+          className="text-[10.5px] font-semibold uppercase tracking-[0.18em] mb-1.5"
+          style={{ color: "hsl(var(--surface-ink-3))" }}
+        >
           Diff · no deltas
         </div>
-        <div className="text-[13.5px] text-muted-foreground">
+        <div
+          className="text-[13.5px]"
+          style={{ color: "hsl(var(--surface-ink-2))" }}
+        >
           These two batches are identical — no claims added, removed, or
           changed between A and B.
         </div>

src/components/BatchesList.tsx

@@ -20,6 +20,11 @@ import type { BatchSummary } from "@/lib/api";
  *
  * Voice mirrors `AckCodeBadge` in `src/pages/Acks.tsx` (uppercase,
  * wide tracking, hairline border, low-opacity fill).
+ *
+ * The literal class names `text-sky-300` and `text-amber-300` are
+ * pinned by `Batches.test.tsx` as a contract — the test asserts the
+ * badge's text color is one of these two strings. Don't replace them
+ * with arbitrary HSL values or the test will fail.
  */
 function KindBadge({ kind }: { kind: BatchSummary["kind"] }) {
   const color =
@@ -42,7 +47,8 @@ function KindBadge({ kind }: { kind: BatchSummary["kind"] }) {
 /**
  * Skeleton rows for the batches table. Mirrors the row count used in
  * `Acks.tsx` (5 placeholders) so the loading density matches the rest
- * of the app.
+ * of the app. `data-testid="batches-skeleton"` is pinned by
+ * `Batches.test.tsx`.
  */
 export function BatchesListSkeleton() {
   return (
@@ -63,6 +69,13 @@ type BatchesListProps = {
    */
   openId: string | null;
   onOpen: (id: string) => void;
+  /**
+   * When `paper`, the table sits inside a cream "paper plane" section
+   * and uses the paper-toned color scheme: warm hover, hairline border
+   * in surface-line, surface-ink text. When `dark` (default), the
+   * original dark-mode chrome is used.
+   */
+  tone?: "dark" | "paper";
 };
 
 /**
@@ -71,15 +84,26 @@ type BatchesListProps = {
  * so the numbers tick up from 0 on first render (gives the page a
  * little life on load; consistent with the Dashboard KPI cards).
  */
-export function BatchesList({ items, openId, onOpen }: BatchesListProps) {
+export function BatchesList({
+  items,
+  openId,
+  onOpen,
+  tone = "dark",
+}: BatchesListProps) {
+  const isPaper = tone === "paper";
   return (
-    <Table data-testid="batches-table">
+    <Table data-testid="batches-table" tone={tone}>
       <TableHeader>
         <TableRow>
           <TableHead>Kind</TableHead>
           <TableHead>Batch</TableHead>
           <TableHead>Input file</TableHead>
-          <TableHead className="text-right">Claims</TableHead>
+          <TableHead
+            className="text-right"
+            style={isPaper ? { color: "hsl(var(--surface-ink-2))" } : undefined}
+          >
+            Claims
+          </TableHead>
           <TableHead>Parsed</TableHead>
           <TableHead className="w-6" aria-label="Open" />
         </TableRow>
@@ -93,28 +117,57 @@ export function BatchesList({ items, openId, onOpen }: BatchesListProps) {
             data-open={openId === b.id ? "true" : undefined}
             className={cn(
               "animate-row-flash cursor-pointer",
-              openId === b.id && "bg-muted/40",
+              isPaper && openId === b.id &&
+                "!bg-[hsl(212_85%_95%)] ring-1 ring-inset ring-[hsl(212_100%_45%_/_0.30)]",
+              !isPaper && openId === b.id && "bg-muted/40",
             )}
           >
             <TableCell>
               <KindBadge kind={b.kind} />
             </TableCell>
-            <TableCell className="display num text-[13px]">
+            <TableCell
+              className="display num text-[13px]"
+              style={isPaper ? { color: "hsl(var(--surface-ink))" } : undefined}
+            >
               {b.id}
             </TableCell>
-            <TableCell className="font-mono text-[12px] text-muted-foreground truncate max-w-[280px]">
+            <TableCell
+              className={cn(
+                "font-mono text-[12px] truncate max-w-[280px]",
+                isPaper
+                  ? "text-[hsl(var(--surface-ink-2))]"
+                  : "text-muted-foreground",
+              )}
+            >
               {b.inputFilename}
             </TableCell>
-            <TableCell className="text-right display num text-[13px]">
+            <TableCell
+              className="text-right display num text-[13px]"
+              style={isPaper ? { color: "hsl(var(--surface-ink))" } : undefined}
+            >
               <AnimatedNumber
                 value={b.claimCount}
                 format={(n) => fmt.num(Math.round(n))}
               />
             </TableCell>
-            <TableCell className="text-muted-foreground num text-[12.5px]">
+            <TableCell
+              className={cn(
+                "num text-[12.5px]",
+                isPaper
+                  ? "text-[hsl(var(--surface-ink-3))]"
+                  : "text-muted-foreground",
+              )}
+            >
               {b.parsedAt ? fmt.dateShort(b.parsedAt) : "—"}
             </TableCell>
-            <TableCell className="text-muted-foreground text-right">
+            <TableCell
+              className={cn(
+                "text-right",
+                isPaper
+                  ? "text-[hsl(var(--surface-ink-3))]"
+                  : "text-muted-foreground",
+              )}
+            >
               <span aria-hidden>›</span>
             </TableCell>
           </TableRow>

src/components/ProviderDrawer/ProviderDrawer.test.tsx

@@ -0,0 +1,196 @@
+// @vitest-environment happy-dom
+// ProviderDrawer wires `useProviderDetail` (TanStack Query) and renders
+// a Radix Dialog portal — both need an act-aware, DOM-backed environment
+// or React logs warnings and the portal can't mount.
+(globalThis as { IS_REACT_ACT_ENVIRONMENT?: boolean }).IS_REACT_ACT_ENVIRONMENT = true;
+
+import { afterEach, describe, it, expect, vi } from "vitest";
+import { cleanup, fireEvent, render } from "@testing-library/react";
+import { ApiError } from "@/lib/api";
+import { ProviderDrawer } from "@/components/ProviderDrawer";
+import type { Provider } from "@/types";
+
+// Mock the hook BEFORE the import above is resolved (vitest hoists
+// `vi.mock` to the top of the file regardless of where it appears
+// syntactically). Mocking the hook directly — rather than mocking
+// `api.getProvider` — lets each test pin the hook's exact return shape
+// without standing up a real `QueryClient`.
+//
+// `vi.hoisted` is required because `vi.mock` is hoisted ABOVE top-level
+// `const` declarations — referencing a top-level `vi.fn()` directly from
+// the factory would hit "Cannot access before initialization" at runtime.
+const { useProviderDetail } = vi.hoisted(() => ({
+  useProviderDetail: vi.fn(),
+}));
+vi.mock("@/hooks/useProviderDetail", () => ({
+  useProviderDetail,
+}));
+
+/**
+ * Minimal valid `Provider` fixture — every required key present so the
+ * component typechecks. The fields are what `ProviderOverview` reads,
+ * so the success-path render exercises every prop.
+ */
+const SAMPLE_PROVIDER: Provider = {
+  npi: "1881068062",
+  name: "Montrose Memorial",
+  taxId: "721587149",
+  address: "123 Main St",
+  city: "Montrose",
+  state: "CO",
+  zip: "81401",
+  phone: "(970) 555-1234",
+  claimCount: 184,
+  outstandingAr: 12450,
+};
+
+/**
+ * Configure the mocked hook's return value for a single test. The
+ * `refetch` default is a fresh `vi.fn()` — tests that need to assert
+ * on it can override via `overrides.refetch`.
+ */
+function mockDetail(
+  overrides: Partial<{
+    data: Provider | null;
+    isLoading: boolean;
+    isError: boolean;
+    error: Error | null;
+    refetch: () => void;
+  }> = {}
+) {
+  useProviderDetail.mockReturnValue({
+    data: null,
+    isLoading: false,
+    isError: false,
+    error: null,
+    refetch: vi.fn(),
+    ...overrides,
+  });
+}
+
+// happy-dom keeps `document.body` between tests; without cleanup,
+// `screen.getByText(...)` would find nodes from earlier renders.
+afterEach(() => {
+  cleanup();
+  vi.clearAllMocks();
+});
+
+describe("ProviderDrawer", () => {
+  it("test_renders_nothing_when_npi_is_null", () => {
+    mockDetail({ data: null });
+    render(<ProviderDrawer npi={null} onClose={() => {}} />);
+
+    // No provider content should be in the document when the drawer
+    // is closed — Radix's Dialog gates the portal on `open`.
+    expect(document.body.textContent).not.toContain("Montrose Memorial");
+  });
+
+  it("test_calls_useProviderDetail_with_npi", () => {
+    mockDetail({ data: SAMPLE_PROVIDER });
+    render(<ProviderDrawer npi="1881068062" onClose={() => {}} />);
+
+    expect(useProviderDetail).toHaveBeenCalledWith("1881068062");
+  });
+
+  it("test_renders_provider_overview_on_success", () => {
+    mockDetail({ data: SAMPLE_PROVIDER });
+    render(<ProviderDrawer npi="1881068062" onClose={() => {}} />);
+
+    // ProviderOverview renders NPI + Tax ID as Field values; the
+    // drawer header shows the provider name as the title.
+    expect(document.body.textContent).toContain("Montrose Memorial");
+    expect(document.body.textContent).toContain("1881068062");
+    expect(document.body.textContent).toContain("721587149");
+  });
+
+  it("test_renders_skeleton_while_loading", () => {
+    mockDetail({ isLoading: true });
+    render(<ProviderDrawer npi="1881068062" onClose={() => {}} />);
+
+    // The `Skeleton` primitive sets `aria-busy="true"` — a stable hook
+    // for the loading state that doesn't require a custom testid.
+    expect(document.querySelectorAll('[aria-busy="true"]').length).toBeGreaterThan(0);
+    // And the provider name should NOT have leaked in yet.
+    expect(document.body.textContent).not.toContain("Montrose Memorial");
+  });
+
+  it("test_renders_not_found_error_on_404", () => {
+    mockDetail({ isError: true, error: new ApiError(404, "Provider ghost not found") });
+    render(<ProviderDrawer npi="ghost" onClose={() => {}} />);
+
+    const errEl = document.querySelector('[data-testid="provider-drawer-error-not_found"]');
+    expect(errEl).not.toBeNull();
+    // Body should mention "doesn't exist" — the not_found COPY key.
+    expect(errEl?.textContent).toContain("doesn't exist");
+    // And the retry button should NOT be present (not_found has no
+    // retry affordance — retrying a 404 won't help).
+    expect(document.querySelector('[data-testid="error-retry"]')).toBeNull();
+  });
+
+  it("test_renders_network_error_with_retry", () => {
+    mockDetail({ isError: true, error: new Error("network down") });
+    render(<ProviderDrawer npi="123" onClose={() => {}} />);
+
+    const errEl = document.querySelector('[data-testid="provider-drawer-error-network"]');
+    expect(errEl).not.toBeNull();
+    expect(errEl?.textContent).toContain("Couldn't reach the server");
+
+    // Network variant shows a Retry button.
+    const retryBtn = document.querySelector(
+      '[data-testid="error-retry"]'
+    ) as HTMLButtonElement | null;
+    expect(retryBtn).not.toBeNull();
+  });
+
+  it("test_renders_not_found_branch_in_demo_mode_for_unknown_npi", () => {
+    // Demo-mode fallback: when `api.isConfigured` is false, the hook
+    // reads from the in-memory zustand store instead of fetching. If the
+    // queried NPI isn't in the providers list, the hook returns
+    // `isError: true` with an `ApiError(404, "Provider not found")`.
+    // The drawer's `errorKind` computation must route this to the
+    // `not_found` branch — NOT the generic `network` branch, which
+    // would mislead the user into thinking the server is down when
+    // there is simply no backend configured (or the NPI is just not
+    // in the local store). Regression guard for the `new Error` →
+    // `new ApiError(404, ...)` fix on the demo-mode fallback branch.
+    mockDetail({
+      isError: true,
+      error: new ApiError(404, "Provider not found"),
+    });
+    render(<ProviderDrawer npi="ghost-npi" onClose={() => {}} />);
+
+    // The not_found branch renders — with the "doesn't exist" copy.
+    const notFoundEl = document.querySelector(
+      '[data-testid="provider-drawer-error-not_found"]'
+    );
+    expect(notFoundEl).not.toBeNull();
+    expect(notFoundEl?.textContent).toContain("doesn't exist");
+
+    // And — the whole point of this test — the network branch MUST NOT
+    // be present. A plain `Error` from the demo-mode fallback would
+    // have landed here and shown "Couldn't reach the server", which
+    // is wrong for a known-local-miss.
+    expect(
+      document.querySelector('[data-testid="provider-drawer-error-network"]')
+    ).toBeNull();
+    expect(document.body.textContent).not.toContain("Couldn't reach the server");
+
+    // not_found has no retry affordance — same invariant as the 404
+    // test above, restated here so this test is self-contained as a
+    // regression guard.
+    expect(document.querySelector('[data-testid="error-retry"]')).toBeNull();
+  });
+
+  it("test_close_button_calls_onClose", () => {
+    const onClose = vi.fn<() => void>();
+    mockDetail({ isError: true, error: new Error("network down") });
+    render(<ProviderDrawer npi="123" onClose={onClose} />);
+
+    const closeBtn = document.querySelector(
+      '[data-testid="error-close"]'
+    ) as HTMLButtonElement | null;
+    expect(closeBtn).not.toBeNull();
+    fireEvent.click(closeBtn!);
+    expect(onClose).toHaveBeenCalledTimes(1);
+  });
+});

src/components/ProviderDrawer/ProviderDrawer.tsx

@@ -0,0 +1,87 @@
+import { Dialog, DialogContent } from "@/components/ui/dialog";
+import { ApiError } from "@/lib/api";
+import { DrillDrawerHeader } from "@/components/drill/DrillDrawerHeader";
+import { Skeleton } from "@/components/ui/skeleton";
+import { useProviderDetail } from "@/hooks/useProviderDetail";
+import { ProviderOverview } from "./ProviderOverview";
+import { ProviderDrawerError } from "./ProviderDrawerError";
+
+interface Props {
+  npi: string | null;
+  onClose: () => void;
+}
+
+/**
+ * Provider drill-down drawer (SP21 Task 2.2).
+ *
+ * Side-panel shell that consumes ``useProviderDetail(npi)`` and renders
+ * the Overview tab content (Phase 2 ships only this tab; Phase 3 adds
+ * Claims/Activity tabs once ``recent_claims`` and ``recent_activity``
+ * rendering lands).
+ *
+ * Layout mirrors the ClaimDrawer / RemitDrawer pattern: Radix Dialog
+ * repositioned to the right edge as a fixed-height side panel, with
+ * the shared ``DrillDrawerHeader`` on top and a scrollable body below.
+ * The DialogContent is the flex parent; the header and body stack
+ * naturally inside it without an explicit `calc(100% - 64px)` height
+ * that would couple to DrillDrawerHeader's padding/font sizes.
+ *
+ * Error branching mirrors the peer drawers:
+ *   - `ApiError(404)` → "not_found" (no retry, the provider is gone)
+ *   - anything else   → "network" (retry available)
+ *   - demo mode + unknown NPI → ApiError(404), routes to the same
+ *     "not_found" branch (the hook raises `ApiError(404, "Provider not
+ *     found")` in this case, matching the real backend 404 path).
+ */
+export function ProviderDrawer({ npi, onClose }: Props) {
+  const { data, isLoading, isError, error, refetch } = useProviderDetail(npi);
+
+  const errorKind: "not_found" | "network" | null = isError
+    ? error instanceof ApiError && error.status === 404
+      ? "not_found"
+      : "network"
+    : null;
+
+  return (
+    <Dialog open={npi !== null} onOpenChange={(o) => { if (!o) onClose(); }}>
+      <DialogContent
+        className="fixed right-0 top-0 flex h-full w-full max-w-2xl flex-col translate-x-0 translate-y-0 rounded-none border-l border-border bg-card p-0"
+        aria-describedby={undefined}
+      >
+        {errorKind ? (
+          <ProviderDrawerError
+            kind={errorKind}
+            onRetry={() => {
+              void refetch();
+            }}
+            onClose={onClose}
+          />
+        ) : isLoading || !data ? (
+          <div className="flex h-full flex-col overflow-y-auto">
+            <DrillDrawerHeader
+              eyebrow="Provider"
+              title="Loading…"
+              onClose={onClose}
+            />
+            <div className="space-y-2 p-6">
+              <Skeleton variant="row" />
+              <Skeleton variant="row" />
+              <Skeleton variant="row" />
+            </div>
+          </div>
+        ) : (
+          <div className="flex h-full flex-col overflow-y-auto">
+            <DrillDrawerHeader
+              eyebrow="Provider"
+              title={data.name}
+              onClose={onClose}
+            />
+            <div className="p-6">
+              <ProviderOverview provider={data} />
+            </div>
+          </div>
+        )}
+      </DialogContent>
+    </Dialog>
+  );
+}

src/components/ProviderDrawer/ProviderDrawerError.tsx

@@ -0,0 +1,70 @@
+import { AlertCircle, WifiOff } from "lucide-react";
+import { Button } from "@/components/ui/button";
+
+type ProviderDrawerErrorProps = {
+  kind: "not_found" | "network";
+  onRetry?: () => void;
+  onClose: () => void;
+};
+
+const COPY = {
+  not_found: {
+    eyebrow: "NOT FOUND",
+    message: "This provider doesn't exist or has been removed.",
+  },
+  network: {
+    eyebrow: "CONNECTION",
+    message: "Couldn't reach the server. Check your connection and try again.",
+  },
+} as const;
+
+/**
+ * Error state for the provider drill-down drawer (SP21 Task 2.2).
+ *
+ * Two shapes — `not_found` (the NPI in the URL doesn't resolve on the
+ * server, e.g. a stale deep link) and `network` (the request failed).
+ * The not_found variant has no retry affordance (retrying won't help),
+ * the network variant does when `onRetry` is supplied.
+ *
+ * Visual twin of `RemitDrawerError` / `ClaimDrawerError` so the drawer
+ * family feels like one component family — same icon size, same eyebrow
+ * color, same button spacing.
+ */
+export function ProviderDrawerError({
+  kind,
+  onRetry,
+  onClose,
+}: ProviderDrawerErrorProps) {
+  const { eyebrow, message } = COPY[kind];
+  const Icon = kind === "network" ? WifiOff : AlertCircle;
+
+  return (
+    <div
+      className="flex flex-col items-start gap-4 p-6 bg-[color:var(--m-surface)] text-[color:var(--m-ink-primary)]"
+      role="alert"
+      data-testid={`provider-drawer-error-${kind}`}
+    >
+      <div className="flex items-center gap-2">
+        <Icon
+          className="h-5 w-5 text-[color:var(--m-error)]"
+          strokeWidth={1.75}
+          aria-hidden
+        />
+        <span className="eyebrow text-[color:var(--m-error)]">
+          {eyebrow}
+        </span>
+      </div>
+      <p className="text-sm text-[color:var(--m-ink-secondary)] max-w-sm">{message}</p>
+      <div className="flex items-center gap-2">
+        {kind === "network" && onRetry ? (
+          <Button variant="outline" size="sm" onClick={onRetry} data-testid="error-retry">
+            Retry
+          </Button>
+        ) : null}
+        <Button variant="ghost" size="sm" onClick={onClose} data-testid="error-close">
+          Close
+        </Button>
+      </div>
+    </div>
+  );
+}

src/components/ProviderDrawer/ProviderOverview.tsx

@@ -0,0 +1,43 @@
+import type { Provider } from "@/types";
+import { fmt } from "@/lib/format";
+
+/**
+ * Overview tab content for the provider drill-down drawer (SP21
+ * Task 2.2). Renders the base provider fields in a two-column grid:
+ *
+ *   - Identity: NPI, Tax ID, address, phone
+ *   - Activity: claim count, outstanding AR
+ *
+ * Subsequent tasks (Phase 3) will hang ``recent_claims`` and
+ * ``recent_activity`` off this surface; for now we only render the
+ * base fields the drawer needs to present "who is this provider and
+ * what's their activity shape" at a glance.
+ */
+export function ProviderOverview({ provider }: { provider: Provider }) {
+  return (
+    <div className="space-y-4">
+      <div className="grid grid-cols-2 gap-3">
+        <Field label="NPI" value={provider.npi} mono />
+        <Field label="Tax ID" value={provider.taxId} mono />
+        <Field
+          label="Address"
+          value={`${provider.address}, ${provider.city}, ${provider.state} ${provider.zip}`}
+        />
+        <Field label="Phone" value={provider.phone} mono />
+      </div>
+      <div className="grid grid-cols-2 gap-3 pt-3 border-t border-border/30">
+        <Field label="Claims" value={fmt.num(provider.claimCount)} mono />
+        <Field label="Outstanding AR" value={fmt.usd(provider.outstandingAr)} mono />
+      </div>
+    </div>
+  );
+}
+
+function Field({ label, value, mono }: { label: string; value: string; mono?: boolean }) {
+  return (
+    <div>
+      <div className="eyebrow">{label}</div>
+      <div className={`text-[13px] mt-1 ${mono ? "display mono" : ""}`}>{value}</div>
+    </div>
+  );
+}

src/components/ProviderDrawer/index.ts

@@ -0,0 +1,3 @@
+// Barrel export for the ProviderDrawer module (SP21 Task 2.2).
+
+export { ProviderDrawer } from "./ProviderDrawer";

src/components/drill/DrillDrawerHeader.tsx

@@ -0,0 +1,37 @@
+import { X } from "lucide-react";
+
+interface Props {
+  eyebrow: string;
+  title: string;
+  onClose: () => void;
+}
+
+/**
+ * Shared side-panel header used by every SP21 drill-down drawer
+ * (provider, …future ones). Renders an uppercase eyebrow above a
+ * larger title, with a close button on the right.
+ *
+ * Visual style mirrors the eyebrow + title pattern used elsewhere in
+ * the app (see ``.eyebrow`` in ``src/index.css`` and the
+ * ``DrillDrawerHeader`` usage in ``ClaimDrawerHeader``).
+ */
+export function DrillDrawerHeader({ eyebrow, title, onClose }: Props) {
+  return (
+    <div className="flex items-center justify-between border-b border-border/30 px-6 py-4">
+      <div>
+        <div className="text-[10.5px] font-semibold uppercase tracking-[0.18em] text-muted-foreground">
+          {eyebrow}
+        </div>
+        <h2 className="text-[18px] font-semibold tracking-tight mt-0.5">{title}</h2>
+      </div>
+      <button
+        type="button"
+        onClick={onClose}
+        aria-label="Close drawer"
+        className="rounded-md p-1 text-muted-foreground hover:bg-muted/60 hover:text-foreground focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring"
+      >
+        <X className="h-4 w-4" aria-hidden />
+      </button>
+    </div>
+  );
+}

src/components/drill/DrillStackProvider.test.tsx

@@ -0,0 +1,45 @@
+// @vitest-environment happy-dom
+(globalThis as { IS_REACT_ACT_ENVIRONMENT?: boolean }).IS_REACT_ACT_ENVIRONMENT = true;
+
+import { describe, it, expect } from "vitest";
+import { renderHook, act } from "@testing-library/react";
+import type { ReactNode } from "react";
+import {
+  DrillStackProvider,
+  useDrillStack,
+} from "@/components/drill/DrillStackProvider";
+
+function wrapper({ children }: { children: ReactNode }) {
+  return <DrillStackProvider>{children}</DrillStackProvider>;
+}
+
+describe("DrillStackProvider", () => {
+  it("starts with an empty stack", () => {
+    const { result } = renderHook(() => useDrillStack(), { wrapper });
+    expect(result.current.stack).toEqual([]);
+    expect(result.current.openPeek).toBeInstanceOf(Function);
+    expect(result.current.closeTop).toBeInstanceOf(Function);
+  });
+
+  it("openPeek pushes one entry; closeTop pops it", () => {
+    const { result } = renderHook(() => useDrillStack(), { wrapper });
+    act(() => result.current.openPeek({ kind: "payer", payerId: "SKCO0" }));
+    expect(result.current.stack).toEqual([
+      { kind: "payer", payerId: "SKCO0" },
+    ]);
+    act(() => result.current.closeTop());
+    expect(result.current.stack).toEqual([]);
+  });
+
+  it("openPeek replaces the previous peek when called twice", () => {
+    const { result } = renderHook(() => useDrillStack(), { wrapper });
+    act(() => result.current.openPeek({ kind: "payer", payerId: "A" }));
+    // The hook only governs peeks (the bottom drawer is owned by the
+    // page, URL-backed, and lives outside this stack). When openPeek
+    // is called while a peek is already on the stack, the new peek
+    // replaces the previous one rather than stacking above it.
+    act(() => result.current.openPeek({ kind: "rule", rule: "R050" }));
+    expect(result.current.stack).toHaveLength(1);
+    expect(result.current.stack[0]).toEqual({ kind: "rule", rule: "R050" });
+  });
+});

src/components/drill/DrillStackProvider.tsx

@@ -0,0 +1,53 @@
+import { createContext, useContext, useMemo, type ReactNode } from "react";
+import { create } from "zustand";
+
+export type PeekPayload =
+  | { kind: "payer"; payerId: string }
+  | { kind: "rule"; rule: string };
+
+interface DrillState {
+  stack: PeekPayload[];
+  openPeek: (p: PeekPayload) => void;
+  closeTop: () => void;
+  closeAll: () => void;
+}
+
+// One zustand store per provider instance (factory) so multiple
+// providers (e.g. in tests) don't share state.
+function makeStore() {
+  return create<DrillState>((set) => ({
+    stack: [],
+    openPeek: (p) =>
+      set((s) => ({
+        // Cap at 2 levels total: one drawer + one peek. When called and
+        // the stack already has one peek, replace it.
+        stack: s.stack.length >= 1 ? [p] : [p],
+      })),
+    closeTop: () => set((s) => ({ stack: s.stack.slice(0, -1) })),
+    closeAll: () => set({ stack: [] }),
+  }));
+}
+
+type StoreApi = ReturnType<typeof makeStore>;
+
+const Ctx = createContext<StoreApi | null>(null);
+
+export function DrillStackProvider({ children }: { children: ReactNode }) {
+  // useMemo so the store instance is stable across renders.
+  const store = useMemo(makeStore, []);
+  return <Ctx.Provider value={store}>{children}</Ctx.Provider>;
+}
+
+export function useDrillStack() {
+  const store = useContext(Ctx);
+  if (!store) throw new Error("useDrillStack must be used within DrillStackProvider");
+  // Subscribe to just `stack` so consumers re-render only on stack
+  // changes (not on every state update).
+  const stack = store((s) => s.stack);
+  return {
+    stack,
+    openPeek: store.getState().openPeek,
+    closeTop: store.getState().closeTop,
+    closeAll: store.getState().closeAll,
+  };
+}

src/components/drill/DrillableCell.test.tsx

@@ -0,0 +1,60 @@
+// @vitest-environment happy-dom
+(globalThis as { IS_REACT_ACT_ENVIRONMENT?: boolean }).IS_REACT_ACT_ENVIRONMENT = true;
+
+import { afterEach, describe, it, expect, vi } from "vitest";
+import { cleanup, render, screen, fireEvent } from "@testing-library/react";
+import { DrillableCell } from "@/components/drill/DrillableCell";
+
+// happy-dom keeps `document.body` between tests; without cleanup,
+// `screen.getByRole("button")` finds buttons from earlier renders.
+afterEach(() => cleanup());
+
+describe("DrillableCell", () => {
+  it("renders children, applies hover affordance classes, calls onClick", () => {
+    const onClick = vi.fn();
+    render(
+      <DrillableCell onClick={onClick}>
+        <span>CLM-114</span>
+      </DrillableCell>,
+    );
+    const btn = screen.getByRole("button") as HTMLButtonElement;
+    expect(btn.classList.contains("drillable")).toBe(true);
+    fireEvent.click(btn);
+    expect(onClick).toHaveBeenCalledOnce();
+  });
+
+  it("disabled state hides affordance and blocks click", () => {
+    const onClick = vi.fn();
+    render(
+      <DrillableCell onClick={onClick} disabled>
+        <span>unavailable</span>
+      </DrillableCell>,
+    );
+    const btn = screen.getByRole("button") as HTMLButtonElement;
+    expect(btn.disabled).toBe(true);
+    expect(btn.classList.contains("drillable")).toBe(false);
+  });
+
+  // ---------------------------------------------------------------------
+  // Regression for Task 2.4 — event bubbling.
+  //
+  // DrillableCell renders a <button>, and <button> clicks bubble up the
+  // DOM by default. Claims wraps each row in a <TableRow onClick={...}>
+  // so a click on the provider cell used to (1) navigate to /providers
+  // and then (2) bubble to the row and re-fire buildUrl() on the now-
+  // /providers URL, appending a phantom ?claim=… param. We fix it at
+  // the DrillableCell level so future tables that adopt the component
+  // are correct by default.
+  // ---------------------------------------------------------------------
+  it("test_click_does_not_bubble_to_parent", () => {
+    const parentClick = vi.fn();
+    const { container } = render(
+      <div onClick={parentClick}>
+        <DrillableCell onClick={() => {}}>Click me</DrillableCell>
+      </div>,
+    );
+    const btn = container.querySelector("button")!;
+    fireEvent.click(btn);
+    expect(parentClick).not.toHaveBeenCalled();
+  });
+});

src/components/drill/DrillableCell.tsx

@@ -0,0 +1,54 @@
+import type { MouseEvent, ReactNode } from "react";
+import { cn } from "@/lib/utils";
+
+interface Props {
+  children: ReactNode;
+  /**
+   * Click handler. Receives the underlying React mouse event so we can
+   * call `e.stopPropagation()` before invoking the caller's logic — see
+   * the JSDoc on the component for why this matters when a DrillableCell
+   * is nested inside a row-level click handler.
+   */
+  onClick: (e: MouseEvent<HTMLButtonElement>) => void;
+  disabled?: boolean;
+  /** Optional aria-label; defaults to the visible text content. */
+  ariaLabel?: string;
+}
+
+/**
+ * Wrap any clickable cell with hover-reveal affordance:
+ *   cursor: pointer + accent background tint + trailing "›" chevron,
+ *   applied via the `drillable` class on hover (see `src/index.css`
+ *   in Task 1.4).
+ *
+ * Renders as a <button> (disabled when `disabled`) so it gets keyboard
+ * activation (Enter/Space) and the standard disabled-button semantics.
+ * The `drillable` affordance class is omitted when disabled.
+ *
+ * Calls `e.stopPropagation()` on the button click before invoking the
+ * caller's handler. This prevents the click from bubbling to a
+ * row-level `onClick` (e.g. Claims' `<TableRow onClick={() => open(c.id)}>`),
+ * which would otherwise re-fire `buildUrl()` on the now-navigated URL
+ * and corrupt history. Precedent: `src/components/inbox/Lane.tsx:41`.
+ */
+export function DrillableCell({ children, onClick, disabled, ariaLabel }: Props) {
+  return (
+    <button
+      type="button"
+      onClick={(e) => {
+        e.stopPropagation();
+        onClick(e);
+      }}
+      disabled={disabled}
+      aria-label={ariaLabel}
+      className={cn(
+        !disabled && "drillable",
+        "inline-flex items-center gap-0 rounded-sm border-0 bg-transparent p-0 text-left",
+        "focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-1",
+        disabled && "text-muted-foreground cursor-not-allowed",
+      )}
+    >
+      {children}
+    </button>
+  );
+}

src/components/drill/PayerPeekContent.test.tsx

@@ -0,0 +1,80 @@
+// @vitest-environment happy-dom
+// PayerPeekContent uses useQuery internally via usePayerSummary. We mock
+// that hook here so the component can be rendered without standing up a
+// real QueryClient — same pattern as useClaimDetail.test.ts.
+(globalThis as { IS_REACT_ACT_ENVIRONMENT?: boolean }).IS_REACT_ACT_ENVIRONMENT = true;
+
+import { afterEach, describe, it, expect, vi } from "vitest";
+import { cleanup, render, screen } from "@testing-library/react";
+import { MemoryRouter } from "react-router-dom";
+import type { ReactNode } from "react";
+import { PayerPeekContent } from "@/components/drill/PayerPeekContent";
+
+// Mock the hook BEFORE the import above is resolved (vitest hoists
+// `vi.mock` to the top of the file regardless of where it appears
+// syntactically).
+vi.mock("@/hooks/usePayerSummary", () => ({
+  usePayerSummary: vi.fn(),
+}));
+
+// Importing after vi.mock so we get the mocked reference.
+import { usePayerSummary } from "@/hooks/usePayerSummary";
+
+// happy-dom keeps `document.body` between tests; without cleanup,
+// `screen.getByText(...)` would find nodes from earlier renders.
+afterEach(() => cleanup());
+
+// The component renders <Link>, which requires a router context. A bare
+// MemoryRouter with no initialEntries is enough — the test asserts on the
+// generated href, not on navigation.
+function withRouter(node: ReactNode) {
+  return <MemoryRouter>{node}</MemoryRouter>;
+}
+
+const SAMPLE_PAYER = {
+  payer_id: "SKCO0",
+  name: "CO Medicaid",
+  claim_count: 1247,
+  billed_total: 548000,
+  received_total: 521000,
+  denial_rate: 0.042,
+  top_providers: [{ npi: "1881068062", count: 184 }],
+} as const;
+
+describe("PayerPeekContent", () => {
+  it("renders loading skeleton while fetching", () => {
+    // Idle / in-flight state — `data` undefined, `isLoading` true.
+    // The component renders <Skeleton variant="row" /> rows and no text,
+    // so the regex match for /claims/i must come back null (the
+    // "View all claims" link only renders once data is present).
+    (usePayerSummary as unknown as ReturnType<typeof vi.fn>).mockReturnValue({
+      data: undefined,
+      isLoading: true,
+    });
+
+    render(withRouter(<PayerPeekContent payerId="SKCO0" />));
+    expect(screen.queryByText(/claims/i)).toBeNull();
+  });
+
+  it("renders summary stats when data loads", () => {
+    (usePayerSummary as unknown as ReturnType<typeof vi.fn>).mockReturnValue({
+      data: SAMPLE_PAYER,
+      isLoading: false,
+    });
+
+    render(withRouter(<PayerPeekContent payerId="SKCO0" />));
+
+    expect(screen.getByText("CO Medicaid")).toBeTruthy();
+    // fmt.num(1247) === "1,247" — the "184 claims" line also matches this
+    // regex, but getByText with a regex is fine because we only assert
+    // existence.
+    expect(screen.getByText(/1,247/)).toBeTruthy();
+    expect(screen.getByText("$548,000")).toBeTruthy();
+    // denial_rate is a fraction (0.042); fmt.pct(payer.denial_rate * 100)
+    // yields "4.2%".
+    expect(screen.getByText("4.2%")).toBeTruthy();
+
+    const link = screen.getByRole("link", { name: /view all claims/i });
+    expect(link.getAttribute("href")).toBe("/claims?payer=SKCO0");
+  });
+});

src/components/drill/PayerPeekContent.tsx

@@ -0,0 +1,118 @@
+import { Link } from "react-router-dom";
+import { Skeleton } from "@/components/ui/skeleton";
+import { fmt } from "@/lib/format";
+import { usePayerSummary } from "@/hooks/usePayerSummary";
+import type { PayerSummary } from "@/lib/api";
+
+interface Props {
+  payerId: string;
+}
+
+/**
+ * Peek body for a payer — aggregate stats card shown inside the
+ * centered PeekModal (SP21 universal drill-down).
+ *
+ * Owns its own fetch via `usePayerSummary`; the parent PeekModal only
+ * concerns itself with open/close + title. We deliberately do NOT show
+ * an error state here — the peek is a low-stakes summary, so a silent
+ * retry + skeleton on failure is acceptable (the parent modal still
+ * closes correctly).
+ *
+ * `fmt.pct` does not multiply by 100 (it's just `n.toFixed(d)%`), so the
+ * API's fraction `denial_rate` (0–1) needs `* 100` before formatting —
+ * otherwise the UI would render "0.0%" for everything.
+ */
+export function PayerPeekContent({ payerId }: Props) {
+  const { data, isLoading } = usePayerSummary(payerId);
+  if (isLoading || !data) {
+    return (
+      <div className="space-y-2" aria-busy="true">
+        <Skeleton variant="row" />
+        <Skeleton variant="row" />
+        <Skeleton variant="row" />
+      </div>
+    );
+  }
+  return <Loaded payer={data} />;
+}
+
+function Loaded({ payer }: { payer: PayerSummary }) {
+  return (
+    <div className="space-y-4">
+      <div className="flex items-baseline justify-between gap-3">
+        <div className="display text-[15px] text-foreground truncate">
+          {payer.name}
+        </div>
+        <div className="mono text-[11px] text-muted-foreground">
+          {payer.payer_id}
+        </div>
+      </div>
+      <div className="grid grid-cols-2 gap-3">
+        <Stat label="Claims" value={fmt.num(payer.claim_count)} />
+        <Stat
+          label="Denial rate"
+          value={fmt.pct(payer.denial_rate * 100)}
+        />
+        <Stat
+          label="Billed"
+          value={fmt.usd(payer.billed_total)}
+          accent="accent"
+        />
+        <Stat
+          label="Received"
+          value={fmt.usd(payer.received_total)}
+          accent="success"
+        />
+      </div>
+      {payer.top_providers.length > 0 ? (
+        <div>
+          <div className="eyebrow mb-1.5">Top providers</div>
+          <ul className="text-[12.5px] space-y-1">
+            {payer.top_providers.slice(0, 3).map((p) => (
+              <li
+                key={p.npi}
+                className="flex justify-between gap-3"
+              >
+                <span className="mono">{p.npi}</span>
+                <span className="mono text-muted-foreground">
+                  {fmt.num(p.count)} claims
+                </span>
+              </li>
+            ))}
+          </ul>
+        </div>
+      ) : null}
+      <Link
+        to={`/claims?payer=${encodeURIComponent(payer.payer_id)}`}
+        className="text-[12.5px] text-accent hover:underline"
+      >
+        View all claims →
+      </Link>
+    </div>
+  );
+}
+
+function Stat({
+  label,
+  value,
+  accent,
+}: {
+  label: string;
+  value: string;
+  accent?: "accent" | "success" | "warning";
+}) {
+  const color =
+    accent === "success"
+      ? "text-[hsl(var(--success))]"
+      : accent === "warning"
+        ? "text-[hsl(var(--warning))]"
+        : accent === "accent"
+          ? "text-accent"
+          : "text-foreground";
+  return (
+    <div>
+      <div className="eyebrow">{label}</div>
+      <div className={`display mono text-[16px] mt-1 ${color}`}>{value}</div>
+    </div>
+  );
+}

src/components/drill/PeekModal.test.tsx

@@ -0,0 +1,52 @@
+// @vitest-environment happy-dom
+(globalThis as { IS_REACT_ACT_ENVIRONMENT?: boolean }).IS_REACT_ACT_ENVIRONMENT = true;
+
+import { afterEach, describe, it, expect, vi } from "vitest";
+import { cleanup, render, screen, fireEvent } from "@testing-library/react";
+import { PeekModal } from "@/components/drill/PeekModal";
+
+// happy-dom keeps `document.body` between tests; without cleanup,
+// `screen.getByRole(...)` finds buttons from earlier renders.
+afterEach(() => cleanup());
+
+describe("PeekModal", () => {
+  it("renders title and body when open; close button fires onClose", () => {
+    const onClose = vi.fn();
+    render(
+      <PeekModal
+        open
+        onClose={onClose}
+        eyebrow="Payer"
+        title="CO Medicaid"
+      >
+        <p>1,247 claims</p>
+      </PeekModal>,
+    );
+    expect(screen.getByText("Payer")).toBeTruthy();
+    expect(screen.getByText("CO Medicaid")).toBeTruthy();
+    expect(screen.getByText("1,247 claims")).toBeTruthy();
+    fireEvent.click(screen.getByRole("button", { name: /close/i }));
+    expect(onClose).toHaveBeenCalledOnce();
+  });
+
+  it("renders nothing when closed", () => {
+    const { container } = render(
+      <PeekModal open={false} onClose={() => {}} title="hidden">
+        <p>should not appear</p>
+      </PeekModal>,
+    );
+    // jest-dom's toBeEmptyDOMElement is not installed; assert via raw DOM.
+    expect(container.firstChild).toBeNull();
+  });
+
+  it("esc key closes", () => {
+    const onClose = vi.fn();
+    render(
+      <PeekModal open onClose={onClose} title="t">
+        <p>x</p>
+      </PeekModal>,
+    );
+    fireEvent.keyDown(document.body, { key: "Escape" });
+    expect(onClose).toHaveBeenCalledOnce();
+  });
+});

src/components/drill/PeekModal.tsx

@@ -0,0 +1,35 @@
+import { Dialog, DialogContent } from "@/components/ui/dialog";
+import type { ReactNode } from "react";
+
+interface Props {
+  open: boolean;
+  onClose: () => void;
+  eyebrow?: string;
+  title: string;
+  children: ReactNode;
+}
+
+/**
+ * Centered peek modal — used for cross-reference drills (payer,
+ * validation rule, etc.). Smaller than the right-side Drawer
+ * (max-width: 480px); closes on Esc, backdrop click, and the X button.
+ * No keyboard j/k nav — single record.
+ */
+export function PeekModal({ open, onClose, eyebrow, title, children }: Props) {
+  return (
+    <Dialog open={open} onOpenChange={(o) => { if (!o) onClose(); }}>
+      <DialogContent
+        className="max-w-[480px] w-[90vw]"
+        aria-describedby={undefined}
+      >
+        {eyebrow ? (
+          <div className="text-[10.5px] font-semibold uppercase tracking-[0.18em] text-muted-foreground">
+            {eyebrow}
+          </div>
+        ) : null}
+        <h2 className="text-[18px] font-semibold tracking-tight">{title}</h2>
+        <div className="mt-2">{children}</div>
+      </DialogContent>
+    </Dialog>
+  );
+}

src/components/inbox/InboxHeader.tsx

@@ -1,16 +1,15 @@
 // ---------------------------------------------------------------------------
 // InboxHeader
 //
-// Compact working-surface header: the day/date, a live clock, and the
-// two top-line counts ("N items need eyes" and "N done today") that
-// anchor the operator's day. "Need eyes" is computed by the Inbox
-// page (sum of actionable lanes) and passed in.
-//
-// SP14: payer_rejected (277CA) is now part of the actionable lanes —
-// it's a working-surface rejection that needs operator follow-up.
-// The Inbox page sums it into the needEyes count.
+// Editorial dark hero for the Inbox. Larger than the previous 30px title
+// so it carries weight against the bright lane surface below. "Inbox."
+// is the page's anchor, the day/date sits as a serif italic, and the
+// "N items need eyes / N done today" line replaces the small status
+// pulse with a more dramatic mono announcement.
 // ---------------------------------------------------------------------------
 
+import { fmt } from "@/lib/format";
+
 export function InboxHeader({
   needEyesCount,
   doneTodayCount,
@@ -32,66 +31,152 @@ export function InboxHeader({
 
   return (
     <header
-      className="sticky top-0 z-10 px-6 pt-6 pb-4"
+      className="sticky top-0 z-10 px-6 lg:px-10 pt-6 pb-5"
       style={{
         background: "var(--tt-bg)",
         borderBottom: "1px solid var(--tt-bg-elev)",
       }}
     >
-      <div className="flex items-baseline justify-between gap-4">
-        <div className="flex items-baseline gap-4">
-          <h1
-            className="display tracking-tight"
-            style={{
-              color: "var(--tt-ink)",
-              fontSize: 30,
-              lineHeight: 1,
-            }}
-          >
-            Inbox
-          </h1>
-          <span
-            className="mono uppercase"
-            style={{
-              color: "var(--tt-amber)",
-              fontSize: 11,
-              letterSpacing: "0.18em",
-            }}
-          >
-            · {day} {date}
-          </span>
-        </div>
-        <span
-          className="mono tabular-nums"
+      <div className="relative">
+        {/* Ghost "TRIAGE" watermark — a print-shop stamp behind the title. */}
+        <div
+          aria-hidden
+          className="pointer-events-none select-none absolute inset-x-0 top-1/2 -translate-y-1/2 whitespace-nowrap display text-center"
           style={{
-            color: "var(--tt-ink-dim)",
-            fontSize: 12,
-            letterSpacing: "0.05em",
+            fontSize: "clamp(120px, 18vw, 260px)",
+            letterSpacing: "-0.05em",
+            opacity: 0.05,
+            lineHeight: 1,
+            color: "var(--tt-amber)",
           }}
         >
-          {time}
-        </span>
+          TRIAGE
+        </div>
+
+        <div className="relative flex items-end justify-between gap-6 flex-wrap">
+          <div className="min-w-0 max-w-3xl">
+            <div className="flex items-center gap-3 mb-3">
+              <div
+                className="h-px w-14"
+                style={{ backgroundColor: "var(--tt-amber)" }}
+              />
+              <span
+                className="mono uppercase"
+                style={{
+                  color: "var(--tt-amber)",
+                  fontSize: 11,
+                  letterSpacing: "0.22em",
+                  fontWeight: 600,
+                }}
+              >
+                Inbox · Working surface
+              </span>
+            </div>
+            <h1
+              className="display tracking-[-0.04em]"
+              style={{
+                color: "var(--tt-ink)",
+                fontSize: "clamp(48px, 6vw, 80px)",
+                lineHeight: 0.92,
+                fontWeight: 400,
+              }}
+            >
+              Inbox.
+            </h1>
+            <p
+              className="display italic mt-3"
+              style={{
+                color: "var(--tt-ink-dim)",
+                fontSize: "clamp(15px, 1.4vw, 19px)",
+                lineHeight: 1.4,
+                maxWidth: "44ch",
+              }}
+            >
+              Five lanes, one queue.{" "}
+              <span style={{ color: "var(--tt-amber)" }}>
+                {needEyesCount}
+              </span>{" "}
+              need eyes; {doneTodayCount} are done today.
+            </p>
+          </div>
+
+          <div
+            className="flex flex-col items-start lg:items-end gap-2"
+            aria-label="Day and time"
+          >
+            <div
+              className="mono uppercase"
+              style={{
+                color: "var(--tt-ink-dim)",
+                fontSize: 11,
+                letterSpacing: "0.22em",
+                fontWeight: 500,
+              }}
+            >
+              {day} {date}
+            </div>
+            <div
+              className="display tabular-nums"
+              style={{
+                color: "var(--tt-ink)",
+                fontSize: 26,
+                lineHeight: 1,
+                fontWeight: 400,
+              }}
+            >
+              {time}
+            </div>
+            <div
+              className="mono uppercase"
+              style={{
+                color: "var(--tt-ink-dim)",
+                fontSize: 10,
+                letterSpacing: "0.20em",
+              }}
+            >
+              local
+            </div>
+          </div>
+        </div>
+
+        {/* Live status row — a horizontal "ticker" of the lane counts so
+            the operator can read the queue at a glance. */}
+        <div
+          className="relative mt-5 flex items-center gap-5 flex-wrap mono uppercase"
+          style={{
+            color: "var(--tt-ink-dim)",
+            fontSize: 11,
+            letterSpacing: "0.14em",
+          }}
+        >
+          <div className="flex items-center gap-2">
+            <span
+              aria-hidden
+              className="inline-block w-1.5 h-1.5 rounded-full animate-pulse-dot"
+              style={{ background: "var(--tt-amber)" }}
+            />
+            <span>Live</span>
+          </div>
+          <span className="opacity-50">·</span>
+          <span>
+            <span style={{ color: "var(--tt-amber)", fontWeight: 600 }}>
+              {needEyesCount}
+            </span>{" "}
+            need eyes
+          </span>
+          <span className="opacity-50">·</span>
+          <span>
+            <span style={{ color: "var(--tt-ink)", fontWeight: 600 }}>
+              {doneTodayCount}
+            </span>{" "}
+            done today
+          </span>
+          <span className="opacity-50 hidden sm:inline">·</span>
+          <span className="hidden sm:inline">
+            {fmt.date(new Date().toISOString())}
+          </span>
+        </div>
       </div>
-      <p
-        className="mono mt-2 flex items-center gap-2"
-        style={{
-          color: "var(--tt-ink-dim)",
-          fontSize: 11,
-          letterSpacing: "0.08em",
-          textTransform: "uppercase",
-        }}
-      >
-        <span
-          className="inline-block w-1.5 h-1.5 rounded-full animate-pulse-dot"
-          style={{ background: "var(--tt-amber)" }}
-          aria-hidden
-        />
-        <span style={{ color: "var(--tt-amber)", fontWeight: 600 }}>{needEyesCount}</span>
-        items need eyes
-        <span className="opacity-50">·</span>
-        <span style={{ color: "var(--tt-ink)", fontWeight: 600 }}>{doneTodayCount}</span>
-        done today
-      </p>
     </header>
   );
 }

src/components/ui/table.tsx

@@ -1,87 +1,128 @@
 import * as React from "react";
 import { cn } from "@/lib/utils";
 
-const Table = React.forwardRef<HTMLTableElement, React.HTMLAttributes<HTMLTableElement>>(
-  ({ className, ...props }, ref) => (
-    <div className="relative w-full overflow-auto">
-      <table
-        ref={ref}
-        className={cn("w-full caption-bottom text-sm", className)}
-        {...props}
-      />
+// ---------------------------------------------------------------------------
+// Table
+//
+// Shared table primitive used by Claims, Remittances, Batches, Acks, etc.
+//
+// `tone="paper"` swaps the dark-mode row chrome (muted/20 header, muted/30
+// hover) for paper-toned chrome (cream surface, soft hairline border,
+// tinted hover). Paper-toned tables sit inside the cream "paper plane"
+// sections of the hybrid Magazine Spread layout. The default `tone="dark"`
+// is unchanged from the original look so existing callers keep their
+// behavior. Pages pass the tone prop once on `<Table>` and the children
+// inherit the matching colors via the data-tone attribute — no need to
+// rewrite every TableHead/TableRow/TableCell.
+// ---------------------------------------------------------------------------
+
+type Tone = "dark" | "paper";
+
+type TableProps = React.HTMLAttributes<HTMLTableElement> & {
+  tone?: Tone;
+};
+
+const Table = React.forwardRef<HTMLTableElement, TableProps>(
+  ({ className, tone = "dark", ...props }, ref) => (
+    <div
+      className={cn("relative w-full overflow-auto", className)}
+      data-tone={tone}
+    >
+      <table ref={ref} className="w-full caption-bottom text-sm" {...props} />
     </div>
   )
 );
 Table.displayName = "Table";
 
-const TableHeader = React.forwardRef<
-  HTMLTableSectionElement,
-  React.HTMLAttributes<HTMLTableSectionElement>
->(({ className, ...props }, ref) => (
-  <thead
-    ref={ref}
-    className={cn(
-      "[&_tr]:border-b [&_tr]:border-border/60 [&_tr]:bg-muted/20",
-      className
-    )}
-    {...props}
-  />
-));
+type TableSectionProps = React.HTMLAttributes<HTMLTableSectionElement>;
+
+const TableHeader = React.forwardRef<HTMLTableSectionElement, TableSectionProps>(
+  ({ className, ...props }, ref) => {
+    // Paper-tone: cream-papered header band, soft border, no dark muted fill.
+    return (
+      <thead
+        ref={ref}
+        className={cn(
+          "[&_tr]:border-b [&_tr]:border-border/60 [&_tr]:bg-muted/20",
+          // When the parent <Table> is paper-toned, swap to cream chrome.
+          "[[data-tone=paper]_&]:bg-[hsl(36_22%_92%)]",
+          "[[data-tone=paper]_&]:[&_tr]:bg-[hsl(36_22%_92%)]",
+          "[[data-tone=paper]_&]:[&_tr]:border-[hsl(30_14%_14%_/_0.10)]",
+          className
+        )}
+        {...props}
+      />
+    );
+  }
+);
 TableHeader.displayName = "TableHeader";
 
-const TableBody = React.forwardRef<
-  HTMLTableSectionElement,
-  React.HTMLAttributes<HTMLTableSectionElement>
->(({ className, ...props }, ref) => (
-  <tbody
-    ref={ref}
-    className={cn("[&_tr:last-child]:border-0", className)}
-    {...props}
-  />
-));
+const TableBody = React.forwardRef<HTMLTableSectionElement, TableSectionProps>(
+  ({ className, ...props }, ref) => (
+    <tbody
+      ref={ref}
+      className={cn("[&_tr:last-child]:border-0", className)}
+      {...props}
+    />
+  )
+);
 TableBody.displayName = "TableBody";
 
-const TableRow = React.forwardRef<
-  HTMLTableRowElement,
-  React.HTMLAttributes<HTMLTableRowElement>
->(({ className, ...props }, ref) => (
-  <tr
-    ref={ref}
-    className={cn(
-      "border-b border-border/40 transition-colors hover:bg-muted/30 focus-within:bg-muted/40 data-[state=selected]:bg-muted/50",
-      className
-    )}
-    {...props}
-  />
-));
+type TableRowProps = React.HTMLAttributes<HTMLTableRowElement>;
+
+const TableRow = React.forwardRef<HTMLTableRowElement, TableRowProps>(
+  ({ className, ...props }, ref) => (
+    <tr
+      ref={ref}
+      className={cn(
+        "border-b border-border/40 transition-colors hover:bg-muted/30 focus-within:bg-muted/40 data-[state=selected]:bg-muted/50",
+        // Paper-tone: warm cream hover, soft hairline between rows.
+        "[[data-tone=paper]_&]:border-[hsl(30_14%_14%_/_0.08)]",
+        "[[data-tone=paper]_&]:hover:bg-[hsl(36_22%_94%)]",
+        "[[data-tone=paper]_&]:focus-within:bg-[hsl(36_22%_94%)]",
+        "[[data-tone=paper]_&]:data-[state=selected]:bg-[hsl(212_85%_95%)]",
+        className
+      )}
+      {...props}
+    />
+  )
+);
 TableRow.displayName = "TableRow";
 
-const TableHead = React.forwardRef<
-  HTMLTableCellElement,
-  React.ThHTMLAttributes<HTMLTableCellElement>
->(({ className, scope = "col", ...props }, ref) => (
-  <th
-    ref={ref}
-    scope={scope}
-    className={cn(
-      "h-9 px-4 text-left align-middle text-[10.5px] font-semibold uppercase tracking-[0.14em] text-muted-foreground/80 [&:has([role=checkbox])]:pr-0",
-      className
-    )}
-    {...props}
-  />
-));
+type TableHeadProps = React.ThHTMLAttributes<HTMLTableCellElement>;
+
+const TableHead = React.forwardRef<HTMLTableCellElement, TableHeadProps>(
+  ({ className, scope = "col", ...props }, ref) => (
+    <th
+      ref={ref}
+      scope={scope}
+      className={cn(
+        "h-9 px-4 text-left align-middle text-[10.5px] font-semibold uppercase tracking-[0.14em] text-muted-foreground/80 [&:has([role=checkbox])]:pr-0",
+        // Paper-tone: surface-ink-2 (warm dark) instead of cool muted-foreground.
+        "[[data-tone=paper]_&]:text-[hsl(var(--surface-ink-2))]",
+        className
+      )}
+      {...props}
+    />
+  )
+);
 TableHead.displayName = "TableHead";
 
-const TableCell = React.forwardRef<
-  HTMLTableCellElement,
-  React.TdHTMLAttributes<HTMLTableCellElement>
->(({ className, ...props }, ref) => (
-  <td
-    ref={ref}
-    className={cn("px-4 py-3 align-middle [&:has([role=checkbox])]:pr-0", className)}
-    {...props}
-  />
-));
+const TableCell = React.forwardRef<HTMLTableCellElement, TableHeadProps>(
+  ({ className, ...props }, ref) => (
+    <td
+      ref={ref}
+      className={cn(
+        "px-4 py-3 align-middle [&:has([role=checkbox])]:pr-0",
+        // Paper-tone: warm foreground (surface-ink) for the primary text.
+        "[[data-tone=paper]_&]:text-[hsl(var(--surface-ink))]",
+        className
+      )}
+      {...props}
+    />
+  )
+);
 TableCell.displayName = "TableCell";
 
 export { Table, TableHeader, TableBody, TableRow, TableHead, TableCell };
+export type { Tone as TableTone };

src/data/sampleData.ts

@@ -164,6 +164,12 @@ function buildActivity(claims: Claim[]): Activity[] {
       timestamp: c.submissionDate,
       npi: c.providerNpi,
       amount: c.billedAmount,
+      // SP21 Task 2.5: mirror the backend `recent_activity()` wire
+      // shape so the Dashboard routing helper can find the claim id.
+      // Sample-data remits are never a 1:1 Activity row, so the
+      // remittance id is always null here.
+      claimId: c.id,
+      remittanceId: null,
     };
   });
   return events.sort(

src/hooks/usePayerSummary.ts

@@ -0,0 +1,24 @@
+import { useQuery } from "@tanstack/react-query";
+import { api, type PayerSummary } from "@/lib/api";
+
+/**
+ * Fetch the aggregate payer stats shown in the payer peek modal
+ * (SP21 universal drill-down).
+ *
+ * Caches for 60s — the backend caches the same way, so re-asks inside
+ * that window are free. `retry: 1` because peek content is a low-stakes
+ * summary; one retry on transient failure is enough before falling back
+ * to the error UI.
+ *
+ * When `payerId` is `null` (the peek isn't open), the query is disabled
+ * and the hook returns the idle React-Query state — no fetch.
+ */
+export function usePayerSummary(payerId: string | null) {
+  return useQuery<PayerSummary>({
+    queryKey: ["payer-summary", payerId],
+    queryFn: () => api.getPayerSummary(payerId as string),
+    enabled: payerId !== null,
+    staleTime: 60 * 1000,
+    retry: 1,
+  });
+}

src/hooks/useProviderDetail.ts

@@ -0,0 +1,87 @@
+import { useQuery } from "@tanstack/react-query";
+import { useSyncExternalStore } from "react";
+import { api, ApiError } from "@/lib/api";
+import { useAppStore } from "@/store";
+import type { Provider } from "@/types";
+
+/**
+ * Per-provider detail drawer query (SP21 Task 2.2).
+ *
+ * Twin of `useClaimDetail` — same return shape, same retry semantics,
+ * same demo-mode fallback story. Returns `{ data, isLoading, isError,
+ * error, refetch }`:
+ *  - `npi === null` (drawer closed): the query is disabled and the
+ *    hook short-circuits to the empty drawer state so a closed drawer
+ *    doesn't burn a network request or a TanStack cache slot.
+ *  - `npi` is set AND a backend is configured: fetches
+ *    `GET /api/config/providers/{npi}` via `api.getProvider`. Cached
+ *    60 s — provider directory rows change infrequently, but we still
+ *    want the drawer to refresh when a user reopens it across a long
+ *    session.
+ *  - On 404: the hook's retry predicate short-circuits (no retries) so
+ *    the drawer's not-found state appears immediately rather than
+ *    being masked by three back-to-back retry attempts.
+ *  - `!api.isConfigured` (demo mode): no fetch is issued. The hook
+ *    reads from the in-memory zustand store (`useAppStore.providers`).
+ *    An unknown NPI surfaces as `isError: true` so the drawer's
+ *    error branch handles it instead of spinning on a missing fetch.
+ */
+export function useProviderDetail(npi: string | null): {
+  data: Provider | null;
+  isLoading: boolean;
+  isError: boolean;
+  error: Error | null;
+  refetch: () => void;
+} {
+  const fallback = useSyncExternalStore(
+    (cb) => useAppStore.subscribe(cb),
+    () => useAppStore.getState().providers,
+    () => useAppStore.getState().providers
+  );
+
+  const q = useQuery<Provider>({
+    queryKey: ["provider-detail", npi],
+    queryFn: () => api.getProvider(npi as string),
+    enabled: npi !== null && api.isConfigured,
+    staleTime: 60 * 1000,
+    retry: (failureCount, error) => {
+      if (error instanceof ApiError && error.status === 404) return false;
+      return failureCount < 3;
+    },
+  });
+
+  if (!api.isConfigured) {
+    const provider =
+      npi === null ? null : fallback.find((p) => p.npi === npi) ?? null;
+    return {
+      data: provider,
+      isLoading: false,
+      isError: provider === null && npi !== null,
+      error:
+        provider === null && npi !== null
+          ? new ApiError(404, "Provider not found")
+          : null,
+      refetch: () => {},
+    };
+  }
+
+  if (npi === null) {
+    return {
+      data: null,
+      isLoading: false,
+      isError: false,
+      error: null,
+      refetch: () => {},
+    };
+  }
+
+  return {
+    data: q.data ?? null,
+    isLoading: q.isLoading,
+    isError: q.isError,
+    error: q.error,
+    refetch: () => {
+      void q.refetch();
+    },
+  };
+}

src/hooks/useProviderDrawerUrlState.test.ts

@@ -0,0 +1,217 @@
+// @vitest-environment happy-dom
+// Mirror the IS_REACT_ACT_ENVIRONMENT setup from useDrawerUrlState.test.ts
+// so React doesn't log act() warnings about the createRoot render/unmount
+// and the popstate-driven state updates.
+(globalThis as { IS_REACT_ACT_ENVIRONMENT?: boolean }).IS_REACT_ACT_ENVIRONMENT = true;
+
+import React, { act } from "react";
+import { createRoot, type Root } from "react-dom/client";
+import { describe, expect, it, vi, beforeEach, afterEach } from "vitest";
+import { useProviderDrawerUrlState } from "./useProviderDrawerUrlState";
+
+/**
+ * Minimal renderHook shim — same pattern as the other hook tests.
+ */
+function renderHook<TResult>(setup: () => TResult): {
+  result: { current: TResult | undefined };
+  unmount: () => void;
+} {
+  const result: { current: TResult | undefined } = { current: undefined };
+  const container = document.createElement("div");
+  document.body.appendChild(container);
+
+  function Probe() {
+    result.current = setup();
+    return null;
+  }
+
+  const root: Root = createRoot(container);
+  act(() => {
+    root.render(React.createElement(Probe));
+  });
+
+  return {
+    result,
+    unmount: () => {
+      act(() => root.unmount());
+      container.remove();
+    },
+  };
+}
+
+/**
+ * Point happy-dom's URL at a known value. happy-dom v20 doesn't expose a
+ * writable `window.location.search`, but `window.happyDOM.setURL` updates
+ * the URL the window reports without triggering a navigation — exactly
+ * what we want for mounting the hook at `/providers?provider=NPI` etc.
+ */
+function setLocation(url: string): void {
+  (window as unknown as { happyDOM: { setURL: (u: string) => void } }).happyDOM.setURL(url);
+}
+
+describe("useProviderDrawerUrlState", () => {
+  type PushState = (state: unknown, unused: string, url?: string | URL | null) => void;
+  let pushStateMock: ReturnType<typeof vi.fn<PushState>>;
+  let replaceStateMock: ReturnType<typeof vi.fn<PushState>>;
+
+  beforeEach(() => {
+    pushStateMock = vi.fn();
+    replaceStateMock = vi.fn();
+
+    vi.stubGlobal("history", {
+      pushState: pushStateMock,
+      replaceState: replaceStateMock,
+      state: null,
+    });
+  });
+
+  afterEach(() => {
+    vi.unstubAllGlobals();
+    setLocation("http://localhost/");
+  });
+
+  it("reads the ?provider= param from window.location.search on mount", () => {
+    setLocation("http://localhost/providers?provider=1881068062");
+
+    const { result, unmount } = renderHook(() => useProviderDrawerUrlState());
+
+    expect(result.current?.providerNpi).toBe("1881068062");
+    expect(typeof result.current?.open).toBe("function");
+    expect(typeof result.current?.close).toBe("function");
+    expect(typeof result.current?.setProviderNpi).toBe("function");
+
+    unmount();
+  });
+
+  it("returns null providerNpi when no ?provider= param is set", () => {
+    setLocation("http://localhost/providers");
+
+    const { result, unmount } = renderHook(() => useProviderDrawerUrlState());
+
+    expect(result.current?.providerNpi).toBeNull();
+
+    unmount();
+  });
+
+  it("returns null providerNpi when ?provider= is present but empty", () => {
+    setLocation("http://localhost/providers?provider=");
+
+    const { result, unmount } = renderHook(() => useProviderDrawerUrlState());
+
+    expect(result.current?.providerNpi).toBeNull();
+
+    unmount();
+  });
+
+  it("open(npi) pushes a new history entry containing ?provider=npi", () => {
+    setLocation("http://localhost/providers");
+
+    const { result, unmount } = renderHook(() => useProviderDrawerUrlState());
+
+    act(() => {
+      result.current?.open("1881068062");
+    });
+
+    expect(pushStateMock).toHaveBeenCalledTimes(1);
+    expect(replaceStateMock).not.toHaveBeenCalled();
+    const urlArg = pushStateMock.mock.calls[0][2] as string;
+    expect(urlArg).toContain("?provider=1881068062");
+
+    unmount();
+  });
+
+  it("setProviderNpi(npi) replaces the current history entry (no new entry) and does NOT pushState", () => {
+    setLocation("http://localhost/providers?provider=1881068062");
+
+    const { result, unmount } = renderHook(() => useProviderDrawerUrlState());
+
+    act(() => {
+      result.current?.setProviderNpi("1881068063");
+    });
+
+    expect(replaceStateMock).toHaveBeenCalledTimes(1);
+    expect(pushStateMock).not.toHaveBeenCalled();
+    const urlArg = replaceStateMock.mock.calls[0][2] as string;
+    expect(urlArg).toContain("?provider=1881068063");
+
+    unmount();
+  });
+
+  it("open() and close() preserve other query params (only ?provider= is touched)", () => {
+    setLocation("http://localhost/providers?sort=name&provider=1881068062");
+
+    const { result, unmount } = renderHook(() => useProviderDrawerUrlState());
+
+    act(() => {
+      result.current?.open("1881068063");
+    });
+    const openUrl = pushStateMock.mock.calls[0][2] as string;
+    expect(openUrl).toContain("sort=name");
+    expect(openUrl).toMatch(/[?&]provider=1881068063/);
+
+    act(() => {
+      result.current?.close();
+    });
+    const closeUrl = pushStateMock.mock.calls[1][2] as string;
+    expect(closeUrl).toContain("sort=name");
+    expect(closeUrl).not.toContain("provider=");
+
+    unmount();
+  });
+
+  it("close() pushes a new history entry with the ?provider= param stripped", () => {
+    setLocation("http://localhost/providers?provider=1881068062");
+
+    const { result, unmount } = renderHook(() => useProviderDrawerUrlState());
+
+    act(() => {
+      result.current?.close();
+    });
+
+    expect(pushStateMock).toHaveBeenCalledTimes(1);
+    expect(replaceStateMock).not.toHaveBeenCalled();
+    const urlArg = pushStateMock.mock.calls[0][2] as string;
+    expect(urlArg).not.toContain("?provider=");
+    expect(result.current?.providerNpi).toBeNull();
+
+    unmount();
+  });
+
+  it("updates providerNpi in response to popstate (browser back/forward)", async () => {
+    setLocation("http://localhost/providers?provider=1881068062");
+
+    const { result, unmount } = renderHook(() => useProviderDrawerUrlState());
+
+    expect(result.current?.providerNpi).toBe("1881068062");
+
+    setLocation("http://localhost/providers?provider=1881068063");
+    await act(async () => {
+      window.dispatchEvent(new PopStateEvent("popstate"));
+      await Promise.resolve();
+    });
+
+    expect(result.current?.providerNpi).toBe("1881068063");
+
+    unmount();
+  });
+
+  it("does not collide with the existing ?claim= or ?remit= params (orthogonal keys)", () => {
+    // The providers drawer is independent of the claims and remits
+    // drawers — all three can be open simultaneously in the future, and
+    // the hooks must not stomp each other's URL state. Opening a
+    // provider must leave ?claim= and ?remit= intact.
+    setLocation("http://localhost/?claim=CLM-1&remit=REM-1");
+
+    const { result, unmount } = renderHook(() => useProviderDrawerUrlState());
+
+    act(() => {
+      result.current?.open("1881068062");
+    });
+    const openUrl = pushStateMock.mock.calls[0][2] as string;
+    expect(openUrl).toContain("claim=CLM-1");
+    expect(openUrl).toContain("remit=REM-1");
+    expect(openUrl).toMatch(/[?&]provider=1881068062/);
+
+    unmount();
+  });
+});

src/hooks/useProviderDrawerUrlState.ts

@@ -0,0 +1,102 @@
+import { useCallback, useEffect, useState } from "react";
+
+/**
+ * Read the current `?provider=…` query param off `window.location.search`.
+ * Returns `null` when the param is absent or empty.
+ *
+ * `URLSearchParams` is the standard, locale-free way to parse query
+ * strings in the browser. Using it (rather than hand-rolled string
+ * slicing) means we correctly handle multiple params and percent-encoded
+ * characters in NPIs without surprises.
+ *
+ * Param name is `?provider=` — chosen to mirror the existing
+ * `?provider=NPI` drilldown convention used by the dashboard's
+ * "Top providers" row (so deep links survive across the app) and to
+ * stay alphabetically parallel with `?claim=` and `?remit=` (one-word
+ * tokens, no collision with the existing `MatchedProviderCard`).
+ */
+function readProviderNpi(): string | null {
+  const params = new URLSearchParams(window.location.search);
+  const value = params.get("provider");
+  return value === "" ? null : value;
+}
+
+/**
+ * Build the URL we want to push/replace into history.
+ *
+ * - `providerNpi === null`  →  drop the `?provider=` param, preserving
+ *   any other params (e.g. `?page=2&provider=…` keeps `page=2`).
+ * - `providerNpi !== null`  →  set the param to the new NPI, also
+ *   preserving any other params.
+ *
+ * We return `pathname + search + hash` (a relative URL) rather than the
+ * full href — `history.pushState` accepts a relative URL and rewriting
+ * only the relative form keeps the document's origin stable.
+ */
+function buildUrl(providerNpi: string | null): string {
+  const url = new URL(window.location.href);
+  if (providerNpi === null) {
+    url.searchParams.delete("provider");
+  } else {
+    url.searchParams.set("provider", providerNpi);
+  }
+  return url.pathname + url.search + url.hash;
+}
+
+/**
+ * Per-provider detail drawer URL state (ProviderDrawer).
+ *
+ * Mirrors `useRemitDrawerUrlState` but for the providers drawer — reads
+ * `?provider=` from the URL on mount and keeps the value in sync with
+ * history as the drawer is opened, navigated (j/k), and closed.
+ *
+ *   - `providerNpi`: the NPI parsed from the URL (or `null` when the
+ *     param is absent). React state so consumers re-render on changes.
+ *   - `open(npi)`: pushes a NEW history entry with `?provider={npi}` —
+ *     so the browser Back button returns to the previous page (e.g. the
+ *     providers list) and not just to the previously-open provider.
+ *   - `setProviderNpi(npi)`: REPLACES the current history entry — used
+ *     by the j/k nav handler so j/k moves through the list without
+ *     polluting history with one entry per keystroke.
+ *   - `close()`: pushes a NEW entry that strips the param, so Back from
+ *     the closed drawer returns to whatever page the user was on before
+ *     opening the drawer.
+ *
+ * The hook subscribes to `popstate` so that browser Back/Forward
+ * (which fire popstate rather than our own pushState) propagate into
+ * the React state. Without this, hitting Back would change the URL but
+ * leave the drawer open on the stale NPI.
+ */
+export function useProviderDrawerUrlState(): {
+  providerNpi: string | null;
+  open: (npi: string) => void;
+  close: () => void;
+  setProviderNpi: (npi: string) => void;
+} {
+  const [providerNpi, setProviderNpiState] = useState<string | null>(() => readProviderNpi());
+
+  const open = useCallback((npi: string) => {
+    window.history.pushState(null, "", buildUrl(npi));
+    setProviderNpiState(npi);
+  }, []);
+
+  const setProviderNpi = useCallback((npi: string) => {
+    window.history.replaceState(null, "", buildUrl(npi));
+    setProviderNpiState(npi);
+  }, []);
+
+  const close = useCallback(() => {
+    window.history.pushState(null, "", buildUrl(null));
+    setProviderNpiState(null);
+  }, []);
+
+  useEffect(() => {
+    const onPopState = () => {
+      setProviderNpiState(readProviderNpi());
+    };
+    window.addEventListener("popstate", onPopState);
+    return () => window.removeEventListener("popstate", onPopState);
+  }, []);
+
+  return { providerNpi, open, close, setProviderNpi };
+}

src/index.css

@@ -413,3 +413,18 @@
     animation-duration: 0s !important;
   }
 }
+
+/* Universal drill-down affordance — applied by DrillableCell. */
+.drillable {
+  cursor: pointer;
+  transition: background-color 120ms ease;
+}
+.drillable:hover {
+  background-color: hsl(var(--accent) / 0.08);
+}
+.drillable:hover::after {
+  content: "›";
+  margin-left: 6px;
+  color: hsl(var(--accent));
+  font-weight: 600;
+}

src/lib/api.ts

@@ -16,7 +16,8 @@
  *   - `parse835(...)` mirrors the 837 shape for `/api/parse-835`.
  *   - `health()` GETs `/api/health` and returns `{ status, version }`.
  *   - `listBatches / getBatch / listClaims / listRemittances / listProviders
- *     / listActivity` are plain JSON GETs against the persistence surface.
+ *     / getProvider / listActivity` are plain JSON GETs against the
+ *     persistence surface.
  *   - `listUnmatched / matchRemit / unmatchClaim` hit the reconciliation
  *     surface. POSTs throw `ApiError` so callers can branch on `.status`.
  */
@@ -36,6 +37,7 @@ import type {
   Payer,
   Payer835,
   Payee835,
+  Provider,
   ReassociationTrace,
   UnmatchedClaim,
   UnmatchedResponse,
@@ -586,6 +588,66 @@ async function listProviders<T = unknown>(
   return (await res.json()) as PaginatedResponse<T>;
 }
 
+/**
+ * Fetch one configured provider by NPI, used by the provider drill-down
+ * drawer (SP21 Task 2.2 / 1.6).
+ *
+ * Drives ``GET /api/config/providers/{npi}``. Note the ``/api/config/``
+ * prefix — this is the config-side route namespace, distinct from the
+ * persistence-side ``/api/providers`` used by ``listProviders``. The
+ * response is the full ``Provider`` shape (including the optional
+ * ``recent_claims`` and ``recent_activity`` arrays populated by Task
+ * 1.6 when the backend can serve them).
+ *
+ * Throws ``ApiError`` on non-2xx — including 404, which the drawer may
+ * want to branch on for a "provider no longer configured" state.
+ */
+async function getProvider(npi: string): Promise<Provider> {
+  if (!isConfigured) throw notConfiguredError();
+  const res = await fetch(
+    joinUrl(`/api/config/providers/${encodeURIComponent(npi)}`),
+    { headers: { Accept: "application/json" } }
+  );
+  if (!res.ok) {
+    const detail = await readErrorBody(res);
+    throw new ApiError(res.status, detail || res.statusText);
+  }
+  return (await res.json()) as Provider;
+}
+
+/**
+ * Aggregate stats for one payer, used by the peek modal on Dashboard /
+ * Claims tables (SP21 universal drill-down). Drives
+ * `GET /api/payers/{payer_id}/summary`.
+ *
+ * `denial_rate` is a fraction in `[0, 1]` (the API does NOT pre-multiply).
+ * `top_providers` is the top 3 (or fewer) by claim count, ordered
+ * server-side.
+ */
+export interface PayerSummary {
+  payer_id: string;
+  name: string;
+  claim_count: number;
+  billed_total: number;
+  received_total: number;
+  denial_rate: number;
+  top_providers: Array<{ npi: string; count: number }>;
+}
+
+async function getPayerSummary(payerId: string): Promise<PayerSummary> {
+  if (!isConfigured) throw notConfiguredError();
+  const res = await fetch(
+    joinUrl(`/api/payers/${encodeURIComponent(payerId)}/summary`)
+  );
+  if (!res.ok) {
+    const detail = await readErrorBody(res);
+    throw new Error(
+      `${res.status} ${res.statusText}${detail ? ` — ${detail}` : ""}`
+    );
+  }
+  return (await res.json()) as PayerSummary;
+}
+
 async function listActivity<T = unknown>(
   params: ListActivityParams = {}
 ): Promise<PaginatedResponse<T>> {
@@ -740,6 +802,8 @@ export const api = {
   listRemittances,
   getRemittance,
   listProviders,
+  getProvider,
+  getPayerSummary,
   listActivity,
   listUnmatched,
   matchRemit,

src/lib/event-routing.test.ts

@@ -0,0 +1,86 @@
+import { describe, expect, it } from "vitest";
+import { eventKindToUrl, type RoutableEvent } from "./event-routing";
+
+// A minimal event factory keeps the assertions short and keeps the
+// focus on what the helper actually inspects (kind + the relevant
+// entity-id field for that kind).
+function evt(overrides: Partial<RoutableEvent> & { kind: RoutableEvent["kind"] }): RoutableEvent {
+  return {
+    claimId: null,
+    remittanceId: null,
+    npi: undefined,
+    ...overrides,
+  };
+}
+
+describe("eventKindToUrl", () => {
+  // ----- claim_* → /claims?claim=ID -------------------------------
+  it("routes claim_submitted to /claims?claim=ID", () => {
+    expect(
+      eventKindToUrl(evt({ kind: "claim_submitted", claimId: "CLM-1" })),
+    ).toBe("/claims?claim=CLM-1");
+  });
+
+  it("routes claim_paid to /claims?claim=ID", () => {
+    expect(
+      eventKindToUrl(evt({ kind: "claim_paid", claimId: "CLM-2" })),
+    ).toBe("/claims?claim=CLM-2");
+  });
+
+  it("routes claim_denied to /claims?claim=ID", () => {
+    expect(
+      eventKindToUrl(evt({ kind: "claim_denied", claimId: "CLM-3" })),
+    ).toBe("/claims?claim=CLM-3");
+  });
+
+  it("routes claim_accepted to /claims?claim=ID", () => {
+    expect(
+      eventKindToUrl(evt({ kind: "claim_accepted", claimId: "CLM-4" })),
+    ).toBe("/claims?claim=CLM-4");
+  });
+
+  it("percent-encodes the claim id when it contains special chars", () => {
+    expect(
+      eventKindToUrl(evt({ kind: "claim_paid", claimId: "CLM/1+2" })),
+    ).toBe("/claims?claim=CLM%2F1%2B2");
+  });
+
+  it("returns null for claim_* when claimId is missing", () => {
+    expect(
+      eventKindToUrl(evt({ kind: "claim_paid", claimId: null })),
+    ).toBeNull();
+    expect(
+      eventKindToUrl(evt({ kind: "claim_paid", claimId: undefined })),
+    ).toBeNull();
+  });
+
+  // ----- remit_received → null (Phase 4) --------------------------
+  it("returns null for remit_received (Phase 4 drawer not built yet)", () => {
+    expect(
+      eventKindToUrl(evt({ kind: "remit_received", remittanceId: "REM-1" })),
+    ).toBeNull();
+  });
+
+  // ----- provider_added → /providers?provider=NPI -----------------
+  it("routes provider_added to /providers?provider=NPI", () => {
+    expect(
+      eventKindToUrl(evt({ kind: "provider_added", npi: "1730187395" })),
+    ).toBe("/providers?provider=1730187395");
+  });
+
+  it("returns null for provider_added when npi is missing", () => {
+    expect(eventKindToUrl(evt({ kind: "provider_added", npi: undefined }))).toBeNull();
+  });
+
+  // ----- default branch ------------------------------------------
+  it("returns null for unhandled kinds (manual_match)", () => {
+    expect(eventKindToUrl(evt({ kind: "manual_match" }))).toBeNull();
+  });
+
+  it("returns null for unknown kinds (defensive default)", () => {
+    // Cast through unknown so the type-checker doesn't widen the
+    // literal away from the exhaustive union.
+    const unknown = { kind: "future_kind" } as unknown as RoutableEvent;
+    expect(eventKindToUrl(unknown)).toBeNull();
+  });
+});

src/lib/event-routing.ts

@@ -0,0 +1,55 @@
+import type { Activity } from "@/types";
+
+/**
+ * The minimum an activity event must carry to be routable. Centralizing
+ * this here means callers can pass an `Activity` (full feed row) or a
+ * narrower shape (e.g. a future "activity event" peek payload) — both
+ * satisfy the kind + entity-id fields the helper inspects.
+ *
+ * - `claimId` / `remittanceId` come from the backend `ActivityEvent`
+ *   ORM columns (SP21 Task 2.5). `claimId` is set on `claim_*` events;
+ *   `remittanceId` is set on `remit_received`.
+ * - `npi` is the existing `Activity.npi` field. For `provider_added`
+ *   events the provider NPI IS the entity id (the URL target).
+ */
+export type RoutableEvent = Pick<
+  Activity,
+  "kind" | "claimId" | "remittanceId" | "npi"
+>;
+
+/**
+ * Maps an activity event to the URL the operator should land on when
+ * clicking the event. Used by:
+ *
+ * - Dashboard "Recent activity" card (this PR, Task 2.5).
+ * - `/activity` log page (Task 2.5 wired here; full integration is
+ *   a later task).
+ *
+ * Returns `null` for kinds that don't have a drill target yet, or
+ * when the entity id field is missing on the event. Callers are
+ * expected to surface a "coming soon" toast in that case so the click
+ * still gives feedback.
+ */
+export function eventKindToUrl(event: RoutableEvent): string | null {
+  switch (event.kind) {
+    case "claim_submitted":
+    case "claim_paid":
+    case "claim_denied":
+    case "claim_accepted": {
+      if (!event.claimId) return null;
+      return `/claims?claim=${encodeURIComponent(event.claimId)}`;
+    }
+    case "remit_received":
+      // Phase 4 — the `RemitDrawer` isn't built yet; the helper stays
+      // honest and returns null so the caller's "coming soon" toast
+      // fires. When the drawer lands, the route becomes
+      // `/remittances?remit=${encodeURIComponent(event.remittanceId ?? "")}`.
+      return null;
+    case "provider_added": {
+      if (!event.npi) return null;
+      return `/providers?provider=${encodeURIComponent(event.npi)}`;
+    }
+    default:
+      return null;
+  }
+}

src/pages/Acks.tsx

@@ -1,5 +1,5 @@
 import { useCallback, useState } from "react";
-import { CheckCircle2, Download } from "lucide-react";
+import { CheckCircle2, Download, ShieldCheck } from "lucide-react";
 import {
   Table,
   TableBody,
@@ -27,18 +27,30 @@ import type { Ack } from "@/types";
 function AckCodeBadge({ code }: { code: Ack["ackCode"] }) {
   const color =
     code === "A"
-      ? "text-emerald-400 border-emerald-400/30 bg-emerald-400/10"
-      : code === "E"
-      ? "text-amber-400 border-amber-400/30 bg-amber-400/10"
-      : code === "P"
-      ? "text-amber-400 border-amber-400/30 bg-amber-400/10"
-      : "text-red-400 border-red-400/30 bg-red-400/10";
+      ? {
+          text: "hsl(152 64% 30%)",
+          bg: "hsl(152 50% 88%)",
+          border: "hsl(152 64% 38% / 0.30)",
+        }
+      : code === "R"
+        ? {
+            text: "hsl(358 70% 36%)",
+            bg: "hsl(358 70% 92%)",
+            border: "hsl(358 70% 50% / 0.30)",
+          }
+        : {
+            text: "hsl(36 92% 30%)",
+            bg: "hsl(36 82% 88%)",
+            border: "hsl(36 92% 50% / 0.30)",
+          };
   return (
     <span
-      className={cn(
-        "inline-flex items-center gap-1 rounded-full border px-2 py-0.5 text-[10.5px] font-semibold uppercase tracking-[0.14em]",
-        color,
-      )}
+      className="inline-flex items-center gap-1 rounded-sm border px-2 py-0.5 mono text-[10.5px] font-semibold uppercase tracking-[0.14em]"
+      style={{
+        color: color.text,
+        backgroundColor: color.bg,
+        borderColor: color.border,
+      }}
     >
       {code}
     </span>
@@ -62,26 +74,15 @@ function DownloadButton({ id, sourceBatchId }: { id: number; sourceBatchId: stri
     setBusy(true);
     try {
       const detail = await api.getAck(id);
-      // The detail endpoint returns the raw_json (the parsed
-      // ParseResult999), not the raw X12 text. Use the build_ack
-      // route's serialized form via a fallback: the round-trip
-      // serializer is applied client-side. For v1 we just
-      // serialize the raw_json envelope/segments if we have them.
       const raw =
         (detail as unknown as { raw_999_text?: string }).raw_999_text ??
         (() => {
-          // Build a minimal 999 from raw_json if the server didn't
-          // stash raw_999_text on the detail endpoint. v1's detail
-          // endpoint doesn't carry the regenerated X12, so the
-          // fallback is a stub that round-trips the parsed result.
           return "";
         })();
       if (raw) {
         downloadBlob(`ack-${sourceBatchId}.999`, raw);
       }
     } catch (err) {
-      // Swallow — the operator can retry. The page-level ErrorState
-      // only surfaces fetch errors, not download errors.
       console.error("download 999 failed", err);
     } finally {
       setBusy(false);
@@ -93,10 +94,14 @@ function DownloadButton({ id, sourceBatchId }: { id: number; sourceBatchId: stri
       onClick={onClick}
       disabled={busy}
       className={cn(
-        "inline-flex items-center gap-1.5 rounded-md border border-border/60 px-2 py-1 text-[11.5px] font-medium",
-        "hover:bg-muted/40 transition-colors",
+        "inline-flex items-center gap-1.5 rounded-sm border px-2 py-1 mono text-[10.5px] uppercase tracking-[0.14em] font-semibold transition-colors",
         busy && "opacity-50 cursor-not-allowed",
       )}
+      style={{
+        borderColor: "hsl(30 14% 14% / 0.20)",
+        color: "hsl(var(--surface-ink-2))",
+        backgroundColor: "hsl(36 22% 96%)",
+      }}
       aria-label="Download 999"
     >
       <Download className="h-3 w-3" strokeWidth={1.75} />
@@ -109,11 +114,6 @@ export function Acks() {
   const { data, isLoading, isError, error, refetch } = useAcks({ limit: 100 });
   const items = data?.items ?? [];
 
-  // Row navigation state (SP4-style j/k). `selectedIndex === null`
-  // means "no row focused yet" — the initial render shows no
-  // highlight, and the first j press lands on row 0 (and the first k
-  // press lands on the last row, so the user can quickly jump to
-  // either end of the list).
   const [selectedIndex, setSelectedIndex] = useState<number | null>(null);
   const [helpOpen, setHelpOpen] = useState(false);
 
@@ -129,18 +129,10 @@ export function Acks() {
     setSelectedIndex((i) => {
       if (items.length === 0) return null;
       if (i === null) return items.length - 1;
-      // Add items.length before the modulo so the negative index
-      // (first row → wrap to last) wraps correctly.
       return (i - 1 + items.length) % items.length;
     });
   }, [items.length]);
 
-  // `enabled: !helpOpen` so j/k navigation yields to the cheatsheet
-  // while it's open. The cheatsheet's own dismiss listener still fires
-  // for any non-`?` keypress (including j/k), so pressing j will close
-  // the cheatsheet but won't move the row — exactly the behavior the
-  // user expects: "the cheatsheet is in the way, get it out of my
-  // way; I'll start navigating on the next keypress".
   useRowKeyboard({
     enabled: !helpOpen && items.length > 0,
     onNext: moveNext,
@@ -149,125 +141,693 @@ export function Acks() {
     onToggleHelp: () => setHelpOpen((v) => !v),
   });
 
+  // -----------------------------------------------------------------
+  // Aggregate metrics for the KPI strip
+  // -----------------------------------------------------------------
+  const totals = items.reduce(
+    (acc, a) => ({
+      accepted: acc.accepted + a.acceptedCount,
+      rejected: acc.rejected + a.rejectedCount,
+      received: acc.received + a.receivedCount,
+    }),
+    { accepted: 0, rejected: 0, received: 0 },
+  );
+  const acceptRate =
+    totals.received > 0
+      ? Math.round((totals.accepted / totals.received) * 1000) / 10
+      : 0;
+
+  // -----------------------------------------------------------------
+  // Stagger choreography
+  // -----------------------------------------------------------------
+  const heroDelay = 0;
+  const foldDelay = 220;
+  const titleDelay = 320;
+  const kpiDelay = 460;
+  const tableDelay = 600;
+
   return (
     <>
       <KeyboardCheatsheet
         open={helpOpen}
         onClose={() => setHelpOpen(false)}
       />
-      <div className="space-y-8 animate-fade-in">
-        <header>
-          <div className="text-[10.5px] font-semibold uppercase tracking-[0.18em] text-muted-foreground mb-2 flex items-center gap-2">
-            <span className="inline-block h-px w-6 bg-border" />
-            999 ACKs
+      <div className="space-y-0">
+        {/* =================================================================
+            HERO — DARK EDITORIAL HEADER
+            ================================================================= */}
+        <section
+          className="relative animate-fade-in pt-6 pb-8 lg:pt-9 lg:pb-10"
+          style={{ animationDelay: `${heroDelay}ms` }}
+        >
+          {/* Ghost "999" watermark — a print-shop stamp behind the title */}
+          <div
+            aria-hidden="true"
+            className="pointer-events-none select-none absolute inset-x-0 top-[58%] -translate-y-1/2 whitespace-nowrap display text-center"
+            style={{
+              fontSize: "clamp(180px, 22vw, 320px)",
+              letterSpacing: "-0.05em",
+              opacity: 0.05,
+              lineHeight: 1,
+              color: "hsl(var(--surface-ink))",
+            }}
+          >
+            999
           </div>
-          <h1 className="text-[22px] font-semibold tracking-tight">
-            999 Implementation Acknowledgments
-          </h1>
-          <p className="text-muted-foreground mt-1.5 text-[14px]">
-            999 ACK transaction sets — generated automatically in response to
-            837P ingests, or parsed from inbound 999 uploads.
-          </p>
-        </header>
 
-        {isError ? (
-          <ErrorState
-            message="Couldn't load ACKs from the backend."
-            detail={error instanceof Error ? error.message : String(error)}
-            onRetry={() => refetch()}
-          />
-        ) : null}
-
-        <div className="surface rounded-xl overflow-hidden">
-          {isLoading ? (
-            <div className="p-4 space-y-2">
-              {Array.from({ length: 5 }).map((_, i) => (
-                <Skeleton key={i} variant="row" />
-              ))}
+          <div className="relative z-10 grid grid-cols-1 lg:grid-cols-[1fr,auto] gap-8 items-end mb-7">
+            <div className="min-w-0 max-w-3xl">
+              <div className="flex items-center gap-3 mb-5">
+                <div className="h-px w-14 bg-foreground/25" />
+                <span className="mono text-[12px] uppercase tracking-[0.22em] text-muted-foreground">
+                  999 ACKs · Reference
+                </span>
+                <span
+                  className="mono text-[12px] uppercase tracking-[0.22em] text-muted-foreground/60 hidden sm:inline"
+                  aria-hidden
+                >
+                  · {items.length} on file
+                </span>
+              </div>
+              <h1 className="display text-[48px] sm:text-[64px] lg:text-[80px] leading-[0.92] text-foreground tracking-[-0.04em]">
+                Acknowledgments,{" "}
+                <span className="italic text-muted-foreground/85">received.</span>
+              </h1>
             </div>
-          ) : items.length === 0 ? (
-            <EmptyState
-              eyebrow="999 ACKs · awaiting first 837 with ack=true"
-              message="Upload an 837P with ?ack=true, or parse a 999 file directly to populate this list."
+            <div className="flex flex-col items-start lg:items-end gap-3">
+              <div className="inline-flex items-center gap-2 rounded-full border border-border/60 bg-card/60 px-3.5 py-2 text-[11.5px] mono uppercase tracking-[0.14em] text-muted-foreground backdrop-blur">
+                <ShieldCheck
+                  className="h-3.5 w-3.5"
+                  strokeWidth={1.75}
+                  style={{ color: "hsl(var(--success))" }}
+                />
+                Envelope · accepted / rejected / partial
+              </div>
+              <kbd
+                className="mono text-[10.5px] uppercase tracking-[0.18em] text-muted-foreground/70"
+              >
+                Press <span className="text-foreground">?</span> for shortcuts
+              </kbd>
+            </div>
+          </div>
+
+          <div className="relative z-10 max-w-2xl">
+            <p className="text-[14px] text-muted-foreground leading-relaxed">
+              999 Implementation Acknowledgments — generated automatically in
+              response to 837P ingests, or parsed from inbound 999 uploads.
+              Each row below is a single transaction set with its accept /
+              reject counts and the original X12 to download.
+            </p>
+          </div>
+        </section>
+
+        {/* =================================================================
+            FOLD — TORN PAGE
+            ================================================================= */}
+        <div
+          aria-hidden
+          className="relative h-14 animate-fade-in"
+          style={{ animationDelay: `${foldDelay}ms` }}
+        >
+          <div
+            className="absolute inset-x-0 top-0 h-1/2"
+            style={{
+              background:
+                "linear-gradient(to bottom, hsl(0 0% 0% / 0.55), transparent)",
+            }}
+          />
+          <div
+            className="absolute inset-x-0 bottom-0 h-1/2"
+            style={{
+              background:
+                "linear-gradient(to top, hsl(30 14% 14% / 0.18), transparent)",
+            }}
+          />
+          <div
+            className="absolute inset-x-0 top-1/2 -translate-y-1/2 h-px"
+            style={{
+              background:
+                "linear-gradient(to right, transparent, hsl(30 14% 14% / 0.5) 12%, hsl(30 14% 14% / 0.7) 50%, hsl(30 14% 14% / 0.5) 88%, transparent)",
+            }}
+          />
+          <div
+            className="absolute inset-x-0 top-1/2 -translate-y-1/2 flex justify-between px-2"
+            style={{ pointerEvents: "none" }}
+          >
+            {Array.from({ length: 48 }, (_, i) => (
+              <span
+                key={i}
+                className="block h-[3px] w-[3px] rounded-full"
+                style={{ backgroundColor: "hsl(30 14% 14% / 0.22)" }}
+              />
+            ))}
+          </div>
+          <div className="relative z-10 mx-auto h-full flex items-center justify-center gap-3 bg-background px-4 w-fit">
+            <span
+              className="display italic"
+              style={{ color: "hsl(var(--muted-foreground))", fontSize: 15 }}
+            >
+              ↘
+            </span>
+            <span
+              className="mono uppercase tracking-[0.24em]"
+              style={{
+                color: "hsl(var(--muted-foreground))",
+                fontSize: 11,
+                fontWeight: 500,
+              }}
+            >
+              999 register
+            </span>
+            <span
+              className="display italic"
+              style={{ color: "hsl(var(--muted-foreground))", fontSize: 15 }}
+            >
+              ↙
+            </span>
+          </div>
+        </div>
+
+        {/* =================================================================
+            PAPER PLANE
+            ================================================================= */}
+        <div
+          className="relative max-w-[1280px] mx-auto animate-fade-in-up"
+          style={{
+            animationDelay: `${titleDelay}ms`,
+            backgroundColor: "hsl(var(--surface))",
+            boxShadow:
+              "inset 0 1px 0 0 hsl(0 0% 100% / 0.5), 0 1px 0 0 hsl(30 14% 22% / 0.06), 0 30px 80px -24px hsl(0 0% 0% / 0.45)",
+          }}
+        >
+          {/* Paper grain */}
+          <div
+            aria-hidden
+            className="pointer-events-none absolute inset-0 opacity-[0.04]"
+            style={{
+              backgroundImage:
+                "url(\"data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='160' height='160'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/><feColorMatrix values='0 0 0 0 0.1  0 0 0 0 0.08  0 0 0 0 0.05  0 0 0 0.9 0'/></filter><rect width='100%' height='100%' filter='url(%23n)'/></svg>\")",
+              backgroundSize: "160px 160px",
+              mixBlendMode: "multiply",
+            }}
+          />
+
+          {/* Title block */}
+          <div className="relative px-8 lg:px-14 pt-12 pb-9 border-b border-[hsl(30_14%_14%/_0.12)]">
+            <div
+              aria-hidden
+              className="absolute left-7 lg:left-12 top-0 bottom-0 w-px"
+              style={{ backgroundColor: "hsl(30 14% 14% / 0.14)" }}
             />
-          ) : (
-            <Table>
-              <TableHeader>
-                <TableRow>
-                  <TableHead className="w-12" aria-label="Status" />
-                  <TableHead>ID</TableHead>
-                  <TableHead>Source Batch</TableHead>
-                  <TableHead className="text-right">Accepted</TableHead>
-                  <TableHead className="text-right">Rejected</TableHead>
-                  <TableHead className="text-right">Received</TableHead>
-                  <TableHead>ACK Code</TableHead>
-                  <TableHead>Parsed</TableHead>
-                  <TableHead className="w-20" aria-label="Download" />
-                </TableRow>
-              </TableHeader>
-              <TableBody>
-                {items.map((a, idx) => {
-                  const isSelected = selectedIndex === idx;
-                  return (
-                    <TableRow
-                      key={a.id}
-                      data-row-index={idx}
-                      data-state={isSelected ? "selected" : undefined}
-                      aria-selected={isSelected}
-                      className={cn(
-                        isSelected && [
-                          // Accent-tinted bg + ring + left strip make the
-                          // selected row clearly stand out from the
-                          // default `hover:bg-muted/30` and the
-                          // `data-[state=selected]:bg-muted` that the
-                          // TableRow primitive applies. Tailwind's
-                          // `accent` token is the same accent used
-                          // elsewhere in the app (nav-active indicator,
-                          // row-flash keyframe, focus ring).
-                          "bg-accent/10 ring-1 ring-inset ring-accent/40 shadow-[inset_2px_0_0_0_hsl(var(--accent))]",
-                        ],
-                      )}
-                    >
-                      <TableCell className="text-muted-foreground">
-                        <CheckCircle2
-                          className={cn(
-                            "h-3.5 w-3.5",
-                            a.ackCode === "A" ? "text-emerald-400" : a.ackCode === "R" ? "text-red-400" : "text-amber-400",
-                          )}
-                          strokeWidth={1.75}
-                          aria-hidden
+            <div className="flex items-end justify-between gap-8 flex-wrap">
+              <div>
+                <div
+                  className="mono text-[12px] uppercase tracking-[0.24em] mb-4 font-medium"
+                  style={{ color: "hsl(var(--surface-ink-3))" }}
+                >
+                  Register · 999 Implementation ACKs
+                </div>
+                <h2
+                  className="display leading-[0.92] tracking-[-0.04em]"
+                  style={{
+                    color: "hsl(var(--surface-ink))",
+                    fontSize: "clamp(48px, 7vw, 96px)",
+                    fontWeight: 400,
+                  }}
+                >
+                  The register.
+                </h2>
+                <div
+                  className="mt-4 display italic"
+                  style={{
+                    color: "hsl(var(--surface-ink-2))",
+                    fontSize: "clamp(15px, 1.3vw, 18px)",
+                    lineHeight: 1.4,
+                    maxWidth: "32ch",
+                  }}
+                >
+                  One row per inbound 999 — the accept / reject / partial
+                  count, the source batch it answers, and the original
+                  transaction set to download.
+                </div>
+              </div>
+              <div className="text-right shrink-0">
+                <div
+                  className="mono text-[11px] uppercase tracking-[0.24em] mb-1.5 font-medium"
+                  style={{ color: "hsl(var(--surface-ink-3))" }}
+                >
+                  On file
+                </div>
+                <div
+                  className="display tabular-nums"
+                  style={{
+                    color: "hsl(var(--surface-ink))",
+                    fontSize: 26,
+                    lineHeight: 1.1,
+                  }}
+                >
+                  {items.length}
+                </div>
+                <div
+                  className="mono text-[11px] mt-1"
+                  style={{ color: "hsl(var(--surface-ink-3))" }}
+                >
+                  999 ACK
+                  {items.length === 1 ? "" : "s"}
+                </div>
+              </div>
+            </div>
+          </div>
+
+          {/* KPI strip — § 01 Vital signs */}
+          <section
+            aria-label="Aggregate ACK metrics"
+            className="relative px-8 lg:px-14 py-7 animate-fade-in-up"
+            style={{ animationDelay: `${kpiDelay}ms` }}
+          >
+            <div
+              aria-hidden
+              className="absolute left-7 lg:left-12 top-7 flex flex-col items-center gap-1"
+            >
+              <span
+                className="mono text-[10px] uppercase tracking-[0.18em] font-semibold"
+                style={{ color: "hsl(var(--surface-ink-3))" }}
+              >
+                § 01
+              </span>
+              <div
+                className="w-px h-10"
+                style={{ backgroundColor: "hsl(30 14% 14% / 0.18)" }}
+              />
+              <span
+                className="display italic"
+                style={{
+                  color: "hsl(var(--surface-ink-2))",
+                  fontSize: 11,
+                  writingMode: "vertical-rl",
+                  transform: "rotate(180deg)",
+                  letterSpacing: "0.16em",
+                }}
+              >
+                Vital signs
+              </span>
+            </div>
+            <div className="grid grid-cols-2 md:grid-cols-4 gap-4">
+              <AckKpiTile
+                label="Accepted"
+                value={totals.accepted}
+                tone="success"
+              />
+              <AckKpiTile
+                label="Rejected"
+                value={totals.rejected}
+                tone="destructive"
+              />
+              <AckKpiTile
+                label="Received"
+                value={totals.received}
+                tone="ink"
+              />
+              <AckKpiTile
+                label="Accept rate"
+                value={`${acceptRate}%`}
+                tone="blue"
+                numeric={false}
+              />
+            </div>
+          </section>
+
+          {/* Table — § 02 The register */}
+          <section
+            aria-label="ACK register"
+            className="relative px-8 lg:px-14 pb-8 lg:pb-10 animate-fade-in-up"
+            style={{ animationDelay: `${tableDelay}ms` }}
+          >
+            <div
+              aria-hidden
+              className="absolute left-7 lg:left-12 top-9 flex flex-col items-center gap-1"
+            >
+              <span
+                className="mono text-[10px] uppercase tracking-[0.18em] font-semibold"
+                style={{ color: "hsl(var(--surface-ink-3))" }}
+              >
+                § 02
+              </span>
+              <div
+                className="w-px h-12"
+                style={{ backgroundColor: "hsl(30 14% 14% / 0.18)" }}
+              />
+              <span
+                className="display italic"
+                style={{
+                  color: "hsl(var(--surface-ink-2))",
+                  fontSize: 11,
+                  writingMode: "vertical-rl",
+                  transform: "rotate(180deg)",
+                  letterSpacing: "0.16em",
+                }}
+              >
+                The register
+              </span>
+            </div>
+
+            <div
+              className="pt-6 border-t"
+              style={{
+                borderTopStyle: "double",
+                borderTopWidth: 3,
+                borderColor: "hsl(30 14% 14% / 0.12)",
+              }}
+            >
+              <div className="flex items-end justify-between gap-6 flex-wrap mb-5">
+                <div>
+                  <div
+                    className="mono text-[11.5px] uppercase tracking-[0.24em] font-semibold mb-2"
+                    style={{ color: "hsl(var(--surface-ink-3))" }}
+                  >
+                    The register
+                  </div>
+                  <h3
+                    className="display leading-[0.98] tracking-[-0.03em]"
+                    style={{
+                      color: "hsl(var(--surface-ink))",
+                      fontSize: "clamp(24px, 2.6vw, 32px)",
+                      fontWeight: 400,
+                    }}
+                  >
+                    All <span className="italic">999s</span>, newest first.
+                  </h3>
+                </div>
+                <div
+                  className="text-[12.5px] display italic"
+                  style={{ color: "hsl(var(--surface-ink-2))", maxWidth: 380 }}
+                >
+                  Navigate rows with{" "}
+                  <kbd
+                    className="mono not-italic text-[10.5px] uppercase tracking-[0.14em] px-1 py-0.5 rounded-sm border"
+                    style={{
+                      borderColor: "hsl(30 14% 14% / 0.20)",
+                      color: "hsl(var(--surface-ink))",
+                    }}
+                  >
+                    j
+                  </kbd>{" "}
+                  /{" "}
+                  <kbd
+                    className="mono not-italic text-[10.5px] uppercase tracking-[0.14em] px-1 py-0.5 rounded-sm border"
+                    style={{
+                      borderColor: "hsl(30 14% 14% / 0.20)",
+                      color: "hsl(var(--surface-ink))",
+                    }}
+                  >
+                    k
+                  </kbd>
+                  .
+                </div>
+              </div>
+
+              {isError ? (
+                <div
+                  className="rounded-md border p-5"
+                  style={{
+                    borderColor: "hsl(30 14% 14% / 0.16)",
+                    backgroundColor: "hsl(36 22% 96%)",
+                  }}
+                >
+                  <ErrorState
+                    message="Couldn't load ACKs from the backend."
+                    detail={error instanceof Error ? error.message : String(error)}
+                    onRetry={() => refetch()}
+                  />
+                </div>
+              ) : isLoading ? (
+                <div
+                  className="rounded-md border p-4 space-y-2"
+                  style={{
+                    borderColor: "hsl(30 14% 14% / 0.10)",
+                    backgroundColor: "hsl(36 22% 96%)",
+                  }}
+                >
+                  {Array.from({ length: 5 }).map((_, i) => (
+                    <Skeleton key={i} variant="row" />
+                  ))}
+                </div>
+              ) : items.length === 0 ? (
+                <div
+                  className="rounded-md border p-10 text-center"
+                  style={{
+                    borderColor: "hsl(30 14% 14% / 0.16)",
+                    borderStyle: "dashed",
+                    backgroundColor: "hsl(36 22% 96%)",
+                  }}
+                >
+                  <EmptyState
+                    eyebrow="999 ACKs · awaiting first 837 with ack=true"
+                    message="Upload an 837P with ?ack=true, or parse a 999 file directly to populate this list."
+                  />
+                </div>
+              ) : (
+                <div
+                  className="rounded-md border overflow-hidden"
+                  style={{
+                    borderColor: "hsl(30 14% 14% / 0.10)",
+                    backgroundColor: "hsl(36 22% 98%)",
+                    boxShadow:
+                      "inset 0 1px 0 0 hsl(0 0% 100% / 0.5)",
+                  }}
+                >
+                  <Table tone="paper">
+                    <TableHeader>
+                      <TableRow>
+                        <TableHead
+                          className="w-12"
+                          aria-label="Status"
+                          style={{ color: "hsl(var(--surface-ink-2))" }}
                         />
-                      </TableCell>
-                      <TableCell className="display num text-[13px]">{a.id}</TableCell>
-                      <TableCell className="font-mono text-[12px] text-muted-foreground truncate max-w-[180px]">
-                        {a.sourceBatchId}
-                      </TableCell>
-                      <TableCell className="text-right display num text-emerald-400">
-                        {a.acceptedCount}
-                      </TableCell>
-                      <TableCell className="text-right display num text-red-400">
-                        {a.rejectedCount}
-                      </TableCell>
-                      <TableCell className="text-right display num text-muted-foreground">
-                        {a.receivedCount}
-                      </TableCell>
-                      <TableCell>
-                        <AckCodeBadge code={a.ackCode} />
-                      </TableCell>
-                      <TableCell className="text-muted-foreground num text-[12.5px]">
-                        {a.parsedAt ? fmt.dateShort(a.parsedAt) : "—"}
-                      </TableCell>
-                      <TableCell>
-                        <DownloadButton id={a.id} sourceBatchId={a.sourceBatchId} />
-                      </TableCell>
-                    </TableRow>
-                  );
-                })}
-              </TableBody>
-            </Table>
-          )}
+                        <TableHead style={{ color: "hsl(var(--surface-ink-2))" }}>
+                          ID
+                        </TableHead>
+                        <TableHead style={{ color: "hsl(var(--surface-ink-2))" }}>
+                          Source Batch
+                        </TableHead>
+                        <TableHead
+                          className="text-right"
+                          style={{ color: "hsl(var(--surface-ink-2))" }}
+                        >
+                          Accepted
+                        </TableHead>
+                        <TableHead
+                          className="text-right"
+                          style={{ color: "hsl(var(--surface-ink-2))" }}
+                        >
+                          Rejected
+                        </TableHead>
+                        <TableHead
+                          className="text-right"
+                          style={{ color: "hsl(var(--surface-ink-2))" }}
+                        >
+                          Received
+                        </TableHead>
+                        <TableHead style={{ color: "hsl(var(--surface-ink-2))" }}>
+                          ACK Code
+                        </TableHead>
+                        <TableHead style={{ color: "hsl(var(--surface-ink-2))" }}>
+                          Parsed
+                        </TableHead>
+                        <TableHead
+                          className="w-20"
+                          aria-label="Download"
+                          style={{ color: "hsl(var(--surface-ink-2))" }}
+                        />
+                      </TableRow>
+                    </TableHeader>
+                    <TableBody>
+                      {items.map((a, idx) => {
+                        const isSelected = selectedIndex === idx;
+                        return (
+                          <TableRow
+                            key={a.id}
+                            data-row-index={idx}
+                            data-state={isSelected ? "selected" : undefined}
+                            aria-selected={isSelected}
+                            className={cn(
+                              isSelected && [
+                                "ring-1 ring-inset",
+                              ],
+                            )}
+                            style={
+                              isSelected
+                                ? {
+                                    backgroundColor: "hsl(212 85% 95%)",
+                                    boxShadow:
+                                      "inset 2px 0 0 0 hsl(212 100% 45%)",
+                                  }
+                                : undefined
+                            }
+                          >
+                            <TableCell>
+                              <CheckCircle2
+                                className={cn(
+                                  "h-3.5 w-3.5",
+                                  a.ackCode === "A"
+                                    ? "text-[hsl(152_64%_38%)]"
+                                    : a.ackCode === "R"
+                                      ? "text-[hsl(358_70%_42%)]"
+                                      : "text-[hsl(36_92%_50%)]",
+                                )}
+                                strokeWidth={1.75}
+                                aria-hidden
+                              />
+                            </TableCell>
+                            <TableCell
+                              className="display num text-[13px]"
+                              style={{ color: "hsl(var(--surface-ink))" }}
+                            >
+                              {a.id}
+                            </TableCell>
+                            <TableCell
+                              className="font-mono text-[12px] truncate max-w-[180px]"
+                              style={{ color: "hsl(var(--surface-ink-2))" }}
+                            >
+                              {a.sourceBatchId}
+                            </TableCell>
+                            <TableCell
+                              className="text-right display num"
+                              style={{ color: "hsl(152 64% 32%)" }}
+                            >
+                              {a.acceptedCount}
+                            </TableCell>
+                            <TableCell
+                              className="text-right display num"
+                              style={{ color: "hsl(358 70% 38%)" }}
+                            >
+                              {a.rejectedCount}
+                            </TableCell>
+                            <TableCell
+                              className="text-right display num"
+                              style={{ color: "hsl(var(--surface-ink-2))" }}
+                            >
+                              {a.receivedCount}
+                            </TableCell>
+                            <TableCell>
+                              <AckCodeBadge code={a.ackCode} />
+                            </TableCell>
+                            <TableCell
+                              className="num text-[12.5px]"
+                              style={{ color: "hsl(var(--surface-ink-3))" }}
+                            >
+                              {a.parsedAt ? fmt.dateShort(a.parsedAt) : "—"}
+                            </TableCell>
+                            <TableCell>
+                              <DownloadButton
+                                id={a.id}
+                                sourceBatchId={a.sourceBatchId}
+                              />
+                            </TableCell>
+                          </TableRow>
+                        );
+                      })}
+                    </TableBody>
+                  </Table>
+                </div>
+              )}
+            </div>
+          </section>
+
+          {/* Footer */}
+          <div
+            className="relative px-8 lg:px-14 py-5 border-t flex items-center justify-between mono text-[10.5px] uppercase tracking-[0.18em]"
+            style={{
+              borderColor: "hsl(30 14% 14% / 0.12)",
+              color: "hsl(var(--surface-ink-3))",
+            }}
+          >
+            <span>End of register</span>
+            <span>Cyclone · 999 ACKs</span>
+            <span>
+              {items.length} {items.length === 1 ? "row" : "rows"}
+            </span>
+          </div>
         </div>
       </div>
     </>
   );
 }
+
+// ---------------------------------------------------------------------------
+// AckKpiTile — paper-toned metric for the ACK register.
+// ---------------------------------------------------------------------------
+function AckKpiTile({
+  label,
+  value,
+  tone,
+  numeric = true,
+}: {
+  label: string;
+  value: number | string;
+  tone: "success" | "destructive" | "ink" | "blue";
+  numeric?: boolean;
+}) {
+  const accentMap = {
+    success: "hsl(152 64% 38%)",
+    destructive: "hsl(358 70% 42%)",
+    ink: "hsl(var(--surface-ink))",
+    blue: "hsl(212 100% 45%)",
+  } as const;
+  const tintMap = {
+    success: "hsl(152 50% 88%)",
+    destructive: "hsl(358 70% 92%)",
+    ink: "hsl(36 22% 90%)",
+    blue: "hsl(212 85% 92%)",
+  } as const;
+  const accent = accentMap[tone];
+  const tint = tintMap[tone];
+  return (
+    <div
+      className="relative rounded-xl p-5 overflow-hidden border"
+      style={{
+        backgroundColor: "hsl(var(--surface))",
+        boxShadow:
+          "inset 0 1px 0 0 hsl(0 0% 100% / 0.45), 0 1px 0 0 hsl(30 14% 22% / 0.06), inset 3px 0 0 0 hsl(0 0% 100% / 0.4)",
+        borderColor: "hsl(30 14% 14% / 0.10)",
+      }}
+    >
+      <div
+        aria-hidden
+        className="absolute left-0 top-5 bottom-5 w-[3px] rounded-r-sm"
+        style={{ backgroundColor: accent, opacity: 0.85 }}
+      />
+      <div className="flex items-center justify-between mb-2.5">
+        <div
+          className="mono text-[10px] uppercase tracking-[0.18em] font-semibold"
+          style={{ color: "hsl(var(--surface-ink-3))" }}
+        >
+          {label}
+        </div>
+        <div
+          className="h-5 w-5 rounded-md flex items-center justify-center"
+          style={{ backgroundColor: tint }}
+        >
+          <span
+            className="block h-1.5 w-1.5 rounded-full"
+            style={{ backgroundColor: accent }}
+          />
+        </div>
+      </div>
+      <div
+        className={cn(
+          "tabular-nums tracking-[-0.04em]",
+          numeric ? "display" : "display"
+        )}
+        style={{
+          color: "hsl(var(--surface-ink))",
+          fontSize: "clamp(28px, 3vw, 40px)",
+          lineHeight: 1,
+          fontWeight: 400,
+        }}
+      >
+        {value}
+      </div>
+    </div>
+  );
+}

src/pages/BatchDiff.tsx

@@ -1,6 +1,11 @@
 import { useCallback, useMemo } from "react";
 import { useSearchParams } from "react-router-dom";
-import { GitCompareArrows, CircleDashed, AlertCircle } from "lucide-react";
+import {
+  AlertCircle,
+  ArrowRight,
+  CircleDashed,
+  GitCompareArrows,
+} from "lucide-react";
 import { ApiError } from "@/lib/api";
 import { Button } from "@/components/ui/button";
 import {
@@ -12,7 +17,10 @@ import {
 } from "@/components/ui/select";
 import { EmptyState } from "@/components/ui/empty-state";
 import { ErrorState } from "@/components/ui/error-state";
-import { BatchDiffView, BatchDiffViewSkeleton } from "@/components/BatchDiffView";
+import {
+  BatchDiffView,
+  BatchDiffViewSkeleton,
+} from "@/components/BatchDiffView";
 import { useBatches } from "@/hooks/useBatches";
 import { useBatchDiff } from "@/hooks/useBatchDiff";
 import type { BatchSummary as ApiBatchSummary } from "@/lib/api";
@@ -38,9 +46,11 @@ function readIdsFromParams(params: URLSearchParams): {
 }
 
 // ---------------------------------------------------------------------------
-// Batch picker — one Select dropdown for each side. Keeps the same
-// kind-colored badge inline so the operator can spot which batch is
-// which at a glance.
+// Kind badge — small inline label so the operator can spot which batch
+// is which at a glance. Identical contract to the one in
+// `BatchesList.tsx`; duplicated here because each lives inside a
+// different page surface (the picker is part of this page, the row
+// badge belongs to Batches).
 // ---------------------------------------------------------------------------
 
 function KindBadge({ kind }: { kind: ApiBatchSummary["kind"] }) {
@@ -63,6 +73,7 @@ function KindBadge({ kind }: { kind: ApiBatchSummary["kind"] }) {
 
 function BatchPicker({
   label,
+  side,
   value,
   onChange,
   items,
@@ -70,6 +81,7 @@ function BatchPicker({
   testid,
 }: {
   label: string;
+  side: "A" | "B";
   value: string | null;
   onChange: (id: string) => void;
   items: ApiBatchSummary[];
@@ -85,10 +97,54 @@ function BatchPicker({
     [items, excludeId],
   );
   const selected = items.find((it) => it.id === value);
+  const accent = side === "A" ? "hsl(212 100% 45%)" : "hsl(36 92% 50%)";
+  const tint = side === "A" ? "hsl(212 85% 95%)" : "hsl(36 82% 92%)";
   return (
-    <div className="space-y-1.5" data-testid={testid}>
-      <div className="text-[10.5px] font-semibold uppercase tracking-[0.18em] text-muted-foreground">
-        {label}
+    <div
+      className="rounded-xl border p-4 space-y-2"
+      data-testid={testid}
+      style={{
+        backgroundColor: "hsl(36 22% 98%)",
+        borderColor: "hsl(30 14% 14% / 0.10)",
+        boxShadow:
+          "inset 0 1px 0 0 hsl(0 0% 100% / 0.45), 0 1px 0 0 hsl(30 14% 22% / 0.06)",
+      }}
+    >
+      <div
+        aria-hidden
+        className="absolute left-0 top-4 bottom-4 w-[3px] rounded-r-sm"
+        style={{ backgroundColor: accent, opacity: 0.85 }}
+      />
+      <div className="flex items-center justify-between">
+        <div className="flex items-center gap-2.5">
+          <div
+            aria-hidden
+            className="h-5 w-5 rounded-md flex items-center justify-center mono font-semibold"
+            style={{ backgroundColor: tint, color: accent, fontSize: 11 }}
+          >
+            {side}
+          </div>
+          <span
+            className="mono text-[10.5px] uppercase tracking-[0.18em] font-semibold"
+            style={{ color: "hsl(var(--surface-ink-3))" }}
+          >
+            {label}
+          </span>
+        </div>
+        {selected ? (
+          <span
+            className="display tabular-nums text-[12.5px]"
+            style={{ color: "hsl(var(--surface-ink-2))" }}
+          >
+            {selected.claimCount}{" "}
+            <span
+              className="mono not-italic uppercase tracking-[0.14em] text-[10px]"
+              style={{ color: "hsl(var(--surface-ink-3))" }}
+            >
+              claims
+            </span>
+          </span>
+        ) : null}
       </div>
       <Select value={value ?? ""} onValueChange={(v) => onChange(v)}>
         <SelectTrigger>
@@ -96,7 +152,10 @@ function BatchPicker({
             <span className="flex items-center gap-2 truncate">
               <KindBadge kind={selected.kind} />
               <span className="font-mono num text-[12.5px]">{selected.id}</span>
-              <span className="text-muted-foreground text-[12px] truncate">
+              <span
+                className="text-[12px] truncate"
+                style={{ color: "hsl(var(--surface-ink-2))" }}
+              >
                 · {selected.inputFilename}
               </span>
             </span>
@@ -157,6 +216,50 @@ function NotFoundState({
   );
 }
 
+// ---------------------------------------------------------------------------
+// Section header — § N + small italic vertical-rl label. Reused by
+// both the picks and diff sections so the folio is uniform.
+// ---------------------------------------------------------------------------
+
+function Folio({ section, label, topClass = "top-7" }: {
+  section: string;
+  label: string;
+  topClass?: string;
+}) {
+  return (
+    <div
+      aria-hidden
+      className={cn(
+        "absolute left-7 lg:left-12 flex flex-col items-center gap-1",
+        topClass,
+      )}
+    >
+      <span
+        className="mono text-[10px] uppercase tracking-[0.18em] font-semibold"
+        style={{ color: "hsl(var(--surface-ink-3))" }}
+      >
+        {section}
+      </span>
+      <div
+        className="w-px h-10"
+        style={{ backgroundColor: "hsl(30 14% 14% / 0.18)" }}
+      />
+      <span
+        className="display italic"
+        style={{
+          color: "hsl(var(--surface-ink-2))",
+          fontSize: 11,
+          writingMode: "vertical-rl",
+          transform: "rotate(180deg)",
+          letterSpacing: "0.16em",
+        }}
+      >
+        {label}
+      </span>
+    </div>
+  );
+}
+
 // ---------------------------------------------------------------------------
 // Page
 // ---------------------------------------------------------------------------
@@ -193,8 +296,13 @@ export function BatchDiff() {
   );
   const reset = useCallback(() => updateIds({ a: null, b: null }), [updateIds]);
 
-  const { data: batches, isLoading: loadingBatches, isError: batchesError, error: batchesErrorMsg, refetch: refetchBatches } =
-    useBatches(100);
+  const {
+    data: batches,
+    isLoading: loadingBatches,
+    isError: batchesError,
+    error: batchesErrorMsg,
+    refetch: refetchBatches,
+  } = useBatches(100);
 
   // Only fire the diff once both pickers have a value. The hook also
   // gates on this internally (defense-in-depth), so a half-picked URL
@@ -209,112 +317,524 @@ export function BatchDiff() {
       : "network"
     : null;
 
+  // -----------------------------------------------------------------
+  // Stagger choreography
+  // -----------------------------------------------------------------
+  const heroDelay = 0;
+  const foldDelay = 220;
+  const titleDelay = 320;
+  const picksDelay = 460;
+  const diffDelay = 600;
+
   // --- render -------------------------------------------------------
   return (
-    <div className="space-y-6 md:space-y-8 animate-fade-in" data-testid="batch-diff-page">
-      <header>
-        <div className="text-[10.5px] font-semibold uppercase tracking-[0.18em] text-muted-foreground mb-2 flex items-center gap-2">
-          <span className="inline-block h-px w-6 bg-border" />
-          Diff
+    <div
+      className="space-y-0 animate-fade-in"
+      data-testid="batch-diff-page"
+    >
+      {/* =================================================================
+          HERO — DARK EDITORIAL HEADER
+          ================================================================= */}
+      <section
+        className="relative pt-6 pb-8 lg:pt-9 lg:pb-10"
+        style={{ animationDelay: `${heroDelay}ms` }}
+      >
+        {/* Ghost "DIFF" watermark — a print-shop stamp behind the title. */}
+        <div
+          aria-hidden="true"
+          className="pointer-events-none select-none absolute inset-x-0 top-[58%] -translate-y-1/2 whitespace-nowrap display text-center"
+          style={{
+            fontSize: "clamp(160px, 20vw, 300px)",
+            letterSpacing: "-0.05em",
+            opacity: 0.05,
+            lineHeight: 1,
+            color: "hsl(var(--surface-ink))",
+          }}
+        >
+          DIFF
         </div>
-        <h1 className="text-[22px] sm:text-[26px] font-semibold tracking-tight">
-          Batch diff
-        </h1>
-        <p className="text-muted-foreground mt-1.5 text-[14px]">
-          Pick two parsed batches — typically a submitted 837P and its
-          corrected follow-up — and see what was added, removed, or changed
-          between them.
-        </p>
-      </header>
 
-      <div className="surface rounded-xl p-4 grid grid-cols-1 md:grid-cols-2 gap-3 md:gap-4">
-        <BatchPicker
-          label="A · left"
-          value={a}
-          onChange={setA}
-          items={batches ?? []}
-          excludeId={b}
-          testid="diff-picker-a"
+        <div className="relative z-10 grid grid-cols-1 lg:grid-cols-[1fr,auto] gap-8 items-end mb-7">
+          <div className="min-w-0 max-w-3xl">
+            <div className="flex items-center gap-3 mb-5">
+              <div className="h-px w-14 bg-foreground/25" />
+              <span className="mono text-[12px] uppercase tracking-[0.22em] text-muted-foreground">
+                Diff · Sheet 01
+              </span>
+              <span
+                className="mono text-[12px] uppercase tracking-[0.22em] text-muted-foreground/60 hidden sm:inline"
+                aria-hidden
+              >
+                · A vs B
+              </span>
+            </div>
+            <h1 className="display text-[48px] sm:text-[64px] lg:text-[80px] leading-[0.92] text-foreground tracking-[-0.04em]">
+              Compare{" "}
+              <span className="italic text-muted-foreground/85">batches.</span>
+            </h1>
+          </div>
+          <div className="flex flex-col items-start lg:items-end gap-3">
+            <div className="inline-flex items-center gap-2 rounded-full border border-border/60 bg-card/60 px-3.5 py-2 text-[11.5px] mono uppercase tracking-[0.14em] text-muted-foreground backdrop-blur">
+              <GitCompareArrows
+                className="h-3.5 w-3.5"
+                strokeWidth={1.75}
+                style={{ color: "hsl(var(--accent))" }}
+              />
+              837P · 835 · first vs second
+            </div>
+            <kbd
+              className="mono text-[10.5px] uppercase tracking-[0.18em] text-muted-foreground/70"
+            >
+              Pick a batch for each side
+            </kbd>
+          </div>
+        </div>
+
+        <div className="relative z-10 max-w-2xl">
+          <p className="text-[14px] text-muted-foreground leading-relaxed">
+            Pick two parsed batches — typically a submitted 837P and its
+            corrected follow-up — and see what was added, removed, or changed
+            between them.
+          </p>
+        </div>
+      </section>
+
+      {/* =================================================================
+          FOLD — TORN PAGE
+          ================================================================= */}
+      <div
+        aria-hidden
+        className="relative h-14"
+        style={{ animationDelay: `${foldDelay}ms` }}
+      >
+        <div
+          className="absolute inset-x-0 top-0 h-1/2"
+          style={{
+            background:
+              "linear-gradient(to bottom, hsl(0 0% 0% / 0.55), transparent)",
+          }}
         />
-        <BatchPicker
-          label="B · right"
-          value={b}
-          onChange={setB}
-          items={batches ?? []}
-          excludeId={a}
-          testid="diff-picker-b"
+        <div
+          className="absolute inset-x-0 bottom-0 h-1/2"
+          style={{
+            background:
+              "linear-gradient(to top, hsl(30 14% 14% / 0.18), transparent)",
+          }}
         />
+        <div
+          className="absolute inset-x-0 top-1/2 -translate-y-1/2 h-px"
+          style={{
+            background:
+              "linear-gradient(to right, transparent, hsl(30 14% 14% / 0.5) 12%, hsl(30 14% 14% / 0.7) 50%, hsl(30 14% 14% / 0.5) 88%, transparent)",
+          }}
+        />
+        <div
+          className="absolute inset-x-0 top-1/2 -translate-y-1/2 flex justify-between px-2"
+          style={{ pointerEvents: "none" }}
+        >
+          {Array.from({ length: 48 }, (_, i) => (
+            <span
+              key={i}
+              className="block h-[3px] w-[3px] rounded-full"
+              style={{ backgroundColor: "hsl(30 14% 14% / 0.22)" }}
+            />
+          ))}
+        </div>
+        <div className="relative z-10 mx-auto h-full flex items-center justify-center gap-3 bg-background px-4 w-fit">
+          <span
+            className="display italic"
+            style={{ color: "hsl(var(--muted-foreground))", fontSize: 15 }}
+          >
+            ↘
+          </span>
+          <span
+            className="mono uppercase tracking-[0.24em]"
+            style={{
+              color: "hsl(var(--muted-foreground))",
+              fontSize: 11,
+              fontWeight: 500,
+            }}
+          >
+            A → B
+          </span>
+          <span
+            className="display italic"
+            style={{ color: "hsl(var(--muted-foreground))", fontSize: 15 }}
+          >
+            ↙
+          </span>
+        </div>
       </div>
 
-      {batchesError ? (
-        <ErrorState
-          message="Couldn't load batches from the backend."
-          detail={
-            batchesErrorMsg instanceof Error
-              ? batchesErrorMsg.message
-              : String(batchesErrorMsg)
-          }
-          onRetry={() => refetchBatches()}
+      {/* =================================================================
+          PAPER PLANE
+          ================================================================= */}
+      <div
+        className="relative max-w-[1280px] mx-auto"
+        style={{
+          animationDelay: `${titleDelay}ms`,
+          backgroundColor: "hsl(var(--surface))",
+          boxShadow:
+            "inset 0 1px 0 0 hsl(0 0% 100% / 0.5), 0 1px 0 0 hsl(30 14% 22% / 0.06), 0 30px 80px -24px hsl(0 0% 0% / 0.45)",
+        }}
+      >
+        {/* Paper grain */}
+        <div
+          aria-hidden
+          className="pointer-events-none absolute inset-0 opacity-[0.04]"
+          style={{
+            backgroundImage:
+              "url(\"data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='160' height='160'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/><feColorMatrix values='0 0 0 0 0.1  0 0 0 0 0.08  0 0 0 0 0.05  0 0 0 0.9 0'/></filter><rect width='100%' height='100%' filter='url(%23n)'/></svg>\")",
+            backgroundSize: "160px 160px",
+            mixBlendMode: "multiply",
+          }}
         />
-      ) : null}
 
-      {!ready ? (
-        <div className="surface rounded-xl">
-          <EmptyState
-            icon={<GitCompareArrows className="h-4 w-4" strokeWidth={1.5} />}
-            eyebrow="Batch diff · awaiting picks"
-            message="Choose one batch for A and one for B to compute the diff."
+        {/* Title block */}
+        <div
+          className="relative px-8 lg:px-14 pt-12 pb-9 border-b animate-fade-in-up"
+          style={{
+            animationDelay: `${titleDelay}ms`,
+            borderColor: "hsl(30 14% 14% / 0.12)",
+          }}
+        >
+          <div
+            aria-hidden
+            className="absolute left-7 lg:left-12 top-0 bottom-0 w-px"
+            style={{ backgroundColor: "hsl(30 14% 14% / 0.14)" }}
           />
+          <div className="flex items-end justify-between gap-8 flex-wrap">
+            <div>
+              <div
+                className="mono text-[12px] uppercase tracking-[0.24em] mb-4 font-medium"
+                style={{ color: "hsl(var(--surface-ink-3))" }}
+              >
+                Sheet 01 · Compare two batches
+              </div>
+              <h2
+                className="display leading-[0.92] tracking-[-0.04em]"
+                style={{
+                  color: "hsl(var(--surface-ink))",
+                  fontSize: "clamp(48px, 7vw, 96px)",
+                  fontWeight: 400,
+                }}
+              >
+                Compare them.
+              </h2>
+              <div
+                className="mt-4 display italic"
+                style={{
+                  color: "hsl(var(--surface-ink-2))",
+                  fontSize: "clamp(15px, 1.3vw, 18px)",
+                  lineHeight: 1.4,
+                  maxWidth: "32ch",
+                }}
+              >
+                Two picks, three buckets. What the second batch added, what
+                the first batch dropped, and which claims moved between them.
+              </div>
+            </div>
+            <div className="text-right shrink-0">
+              <div
+                className="mono text-[11px] uppercase tracking-[0.24em] mb-1.5 font-medium"
+                style={{ color: "hsl(var(--surface-ink-3))" }}
+              >
+                On the wire
+              </div>
+              <div
+                className="flex items-center justify-end gap-2 tabular-nums"
+                style={{
+                  color: "hsl(var(--surface-ink))",
+                  fontSize: 26,
+                  lineHeight: 1.1,
+                }}
+              >
+                <span
+                  className="display"
+                  style={{ color: a ? "hsl(212 100% 45%)" : "hsl(var(--surface-ink-3))" }}
+                >
+                  {a ? "A" : "—"}
+                </span>
+                <ArrowRight
+                  className="h-4 w-4 mt-0.5"
+                  strokeWidth={1.5}
+                  style={{ color: "hsl(var(--surface-ink-3))" }}
+                />
+                <span
+                  className="display"
+                  style={{ color: b ? "hsl(36 92% 50%)" : "hsl(var(--surface-ink-3))" }}
+                >
+                  {b ? "B" : "—"}
+                </span>
+              </div>
+              <div
+                className="mono text-[11px] mt-1"
+                style={{ color: "hsl(var(--surface-ink-3))" }}
+              >
+                {ready ? "ready to diff" : "two picks needed"}
+              </div>
+            </div>
+          </div>
         </div>
-      ) : loadingBatches ? (
-        <BatchDiffViewSkeleton />
-      ) : errKind === "not_found" ? (
-        <NotFoundState a={a as string} b={b as string} onReset={reset} />
-      ) : diff.isError ? (
-        <ErrorState
-          message="Couldn't compute the diff between these two batches."
-          detail={
-            diff.error instanceof Error
-              ? diff.error.message
-              : String(diff.error)
-          }
-          onRetry={() => diff.refetch()}
-        />
-      ) : diff.isLoading || !diff.data ? (
-        <BatchDiffViewSkeleton />
-      ) : (
-        <BatchDiffView data={diff.data} />
-      )}
 
-      {/* Action footer — always visible so the operator can clear or
-          force-refresh without scrolling back to the picker. */}
-      {ready ? (
-        <div className="flex items-center justify-end gap-2 pt-2">
-          {diff.isFetching ? (
-            <span className="text-[12px] text-muted-foreground inline-flex items-center gap-1.5">
-              <CircleDashed className="h-3 w-3 animate-spin" strokeWidth={1.75} />
-              Refreshing…
-            </span>
-          ) : null}
-          <Button
-            variant="outline"
-            size="sm"
-            onClick={() => diff.refetch()}
-            data-testid="diff-refresh-button"
+        {/* § 01 The picks */}
+        <section
+          aria-label="The picks"
+          className="relative px-8 lg:px-14 py-7 animate-fade-in-up"
+          style={{ animationDelay: `${picksDelay}ms` }}
+        >
+          <Folio section="§ 01" label="The picks" />
+          <div
+            className="pt-6 border-t"
+            style={{
+              borderTopStyle: "double",
+              borderTopWidth: 3,
+              borderColor: "hsl(30 14% 14% / 0.12)",
+            }}
           >
-            Refresh
-          </Button>
-          <Button
-            variant="ghost"
-            size="sm"
-            onClick={reset}
-            data-testid="diff-clear-button"
+            <div className="flex items-end justify-between gap-6 flex-wrap mb-5">
+              <div>
+                <div
+                  className="mono text-[11.5px] uppercase tracking-[0.24em] font-semibold mb-2"
+                  style={{ color: "hsl(var(--surface-ink-3))" }}
+                >
+                  The picks
+                </div>
+                <h3
+                  className="display leading-[0.98] tracking-[-0.03em]"
+                  style={{
+                    color: "hsl(var(--surface-ink))",
+                    fontSize: "clamp(24px, 2.6vw, 32px)",
+                    fontWeight: 400,
+                  }}
+                >
+                  One on each <span className="italic">side.</span>
+                </h3>
+              </div>
+              <div
+                className="text-[12.5px] display italic"
+                style={{ color: "hsl(var(--surface-ink-2))", maxWidth: 380 }}
+              >
+                A is the "before" — B is the "after". A picked batch can't
+                be picked again on the other side.
+              </div>
+            </div>
+            <div className="relative grid grid-cols-1 md:grid-cols-2 gap-4">
+              <BatchPicker
+                label="A · left"
+                side="A"
+                value={a}
+                onChange={setA}
+                items={batches ?? []}
+                excludeId={b}
+                testid="diff-picker-a"
+              />
+              <BatchPicker
+                label="B · right"
+                side="B"
+                value={b}
+                onChange={setB}
+                items={batches ?? []}
+                excludeId={a}
+                testid="diff-picker-b"
+              />
+            </div>
+          </div>
+        </section>
+
+        {/* § 02 The diff */}
+        <section
+          aria-label="The diff"
+          className="relative px-8 lg:px-14 pb-8 lg:pb-10 animate-fade-in-up"
+          style={{ animationDelay: `${diffDelay}ms` }}
+        >
+          <Folio section="§ 02" label="The diff" topClass="top-9" />
+          <div
+            className="pt-6 border-t"
+            style={{
+              borderTopStyle: "double",
+              borderTopWidth: 3,
+              borderColor: "hsl(30 14% 14% / 0.12)",
+            }}
           >
-            <AlertCircle className="h-3.5 w-3.5 mr-1" strokeWidth={1.75} />
-            Clear picks
-          </Button>
+            <div className="flex items-end justify-between gap-6 flex-wrap mb-5">
+              <div>
+                <div
+                  className="mono text-[11.5px] uppercase tracking-[0.24em] font-semibold mb-2"
+                  style={{ color: "hsl(var(--surface-ink-3))" }}
+                >
+                  The diff
+                </div>
+                <h3
+                  className="display leading-[0.98] tracking-[-0.03em]"
+                  style={{
+                    color: "hsl(var(--surface-ink))",
+                    fontSize: "clamp(24px, 2.6vw, 32px)",
+                    fontWeight: 400,
+                  }}
+                >
+                  What <span className="italic">moved.</span>
+                </h3>
+              </div>
+              {ready ? (
+                <div
+                  className="text-[12.5px] display italic"
+                  style={{
+                    color: "hsl(var(--surface-ink-2))",
+                    maxWidth: 380,
+                  }}
+                >
+                  Three buckets — added in B, removed from A, changed in
+                  place. Unchanged claims are summarized but not listed.
+                </div>
+              ) : null}
+            </div>
+
+            {batchesError ? (
+              <div
+                className="rounded-md border p-5"
+                style={{
+                  borderColor: "hsl(30 14% 14% / 0.16)",
+                  backgroundColor: "hsl(36 22% 96%)",
+                }}
+              >
+                <ErrorState
+                  message="Couldn't load batches from the backend."
+                  detail={
+                    batchesErrorMsg instanceof Error
+                      ? batchesErrorMsg.message
+                      : String(batchesErrorMsg)
+                  }
+                  onRetry={() => refetchBatches()}
+                />
+              </div>
+            ) : !ready ? (
+              <div
+                className="rounded-md border p-12 text-center"
+                style={{
+                  borderColor: "hsl(30 14% 14% / 0.16)",
+                  borderStyle: "dashed",
+                  backgroundColor: "hsl(36 22% 96%)",
+                }}
+                data-testid="batch-diff-awaiting"
+              >
+                <EmptyState
+                  icon={
+                    <GitCompareArrows
+                      className="h-4 w-4"
+                      strokeWidth={1.5}
+                    />
+                  }
+                  eyebrow="Batch diff · awaiting picks"
+                  message="Choose one batch for A and one for B to compute the diff."
+                />
+              </div>
+            ) : loadingBatches ? (
+              <BatchDiffViewSkeleton />
+            ) : errKind === "not_found" ? (
+              <NotFoundState a={a as string} b={b as string} onReset={reset} />
+            ) : diff.isError ? (
+              <div
+                className="rounded-md border p-5"
+                style={{
+                  borderColor: "hsl(30 14% 14% / 0.16)",
+                  backgroundColor: "hsl(36 22% 96%)",
+                }}
+              >
+                <ErrorState
+                  message="Couldn't compute the diff between these two batches."
+                  detail={
+                    diff.error instanceof Error
+                      ? diff.error.message
+                      : String(diff.error)
+                  }
+                  onRetry={() => diff.refetch()}
+                />
+              </div>
+            ) : diff.isLoading || !diff.data ? (
+              <BatchDiffViewSkeleton />
+            ) : (
+              <BatchDiffView data={diff.data} />
+            )}
+          </div>
+        </section>
+
+        {/* Action footer — always visible when ready so the operator can
+            clear or force-refresh without scrolling back to the picker. */}
+        {ready ? (
+          <div
+            className="relative px-8 lg:px-14 py-5 border-t flex items-center justify-between gap-3 flex-wrap"
+            style={{
+              borderColor: "hsl(30 14% 14% / 0.12)",
+            }}
+          >
+            <div
+              className="text-[12.5px] display italic"
+              style={{ color: "hsl(var(--surface-ink-2))" }}
+            >
+              {diff.isFetching ? (
+                <span className="inline-flex items-center gap-1.5">
+                  <CircleDashed
+                    className="h-3 w-3 animate-spin"
+                    strokeWidth={1.75}
+                  />
+                  Refreshing…
+                </span>
+              ) : (
+                <>
+                  Comparing{" "}
+                  <span
+                    className="display mono not-italic"
+                    style={{ color: "hsl(var(--surface-ink))" }}
+                  >
+                    {a}
+                  </span>{" "}
+                  with{" "}
+                  <span
+                    className="display mono not-italic"
+                    style={{ color: "hsl(var(--surface-ink))" }}
+                  >
+                    {b}
+                  </span>
+                  .
+                </>
+              )}
+            </div>
+            <div className="flex items-center gap-2 flex-wrap">
+              <Button
+                variant="outline"
+                size="sm"
+                onClick={() => diff.refetch()}
+                data-testid="diff-refresh-button"
+              >
+                Refresh
+              </Button>
+              <Button
+                variant="ghost"
+                size="sm"
+                onClick={reset}
+                data-testid="diff-clear-button"
+              >
+                <AlertCircle className="h-3.5 w-3.5 mr-1" strokeWidth={1.75} />
+                Clear picks
+              </Button>
+            </div>
+          </div>
+        ) : null}
+
+        {/* Footer */}
+        <div
+          className="relative px-8 lg:px-14 py-5 border-t flex items-center justify-between mono text-[10.5px] uppercase tracking-[0.18em]"
+          style={{
+            borderColor: "hsl(30 14% 14% / 0.12)",
+            color: "hsl(var(--surface-ink-3))",
+          }}
+        >
+          <span>End of sheet 01</span>
+          <span>Cyclone · Batch diff</span>
+          <span>{ready ? "A vs B" : "awaiting picks"}</span>
         </div>
-      ) : null}
+      </div>
     </div>
   );
 }

src/pages/Batches.tsx

@@ -1,9 +1,10 @@
 import { useCallback, useEffect, useMemo, useState } from "react";
 import { useQuery } from "@tanstack/react-query";
+import { Files, GitBranch, Layers, Receipt } from "lucide-react";
 import { Dialog, DialogContent } from "@/components/ui/dialog";
 import { EmptyState } from "@/components/ui/empty-state";
 import { ErrorState } from "@/components/ui/error-state";
-import { PageHeader } from "@/components/PageHeader";
+import { Skeleton } from "@/components/ui/skeleton";
 import { BatchesList, BatchesListSkeleton } from "@/components/BatchesList";
 import {
   BatchDetailContent,
@@ -118,6 +119,14 @@ function useBatchDetail(id: string | null): {
 
 const HELP_NOOP = () => {};
 
+/**
+ * Batches page — hybrid Magazine Spread treatment.
+ *
+ * Dark editorial hero → torn-page fold → cream paper plane with the
+ * batch register (KPI strip + tabular list). Click a row to open the
+ * detail drawer (rendered above the page, dimmed via the body
+ * opacity).
+ */
 export function Batches() {
   const { data, isLoading, isError, error, refetch } = useBatches(100);
   const items: BatchSummary[] = data ?? [];
@@ -156,6 +165,28 @@ export function Batches() {
   const dimBackground = batchId !== null;
   const errKind = batchErrorKind(detailError);
 
+  // -----------------------------------------------------------------
+  // Aggregate metrics for the § 01 KPI strip
+  // -----------------------------------------------------------------
+  const totals = items.reduce(
+    (acc, b) => ({
+      count: acc.count + 1,
+      p837: acc.p837 + (b.kind === "837p" ? 1 : 0),
+      p835: acc.p835 + (b.kind === "835" ? 1 : 0),
+      claims: acc.claims + b.claimCount,
+    }),
+    { count: 0, p837: 0, p835: 0, claims: 0 },
+  );
+
+  // -----------------------------------------------------------------
+  // Stagger choreography (matches Acks / Reconciliation / Upload)
+  // -----------------------------------------------------------------
+  const heroDelay = 0;
+  const foldDelay = 220;
+  const titleDelay = 320;
+  const kpiDelay = 460;
+  const tableDelay = 600;
+
   return (
     <>
       <Dialog
@@ -188,37 +219,541 @@ export function Batches() {
       <div
         data-testid="batches-page-body"
         className={cn(
-          "space-y-6 lg:space-y-8 animate-fade-in transition-opacity",
+          "space-y-0 animate-fade-in transition-opacity",
           dimBackground && "pointer-events-none opacity-60",
         )}
       >
-        <PageHeader
-          eyebrow="Batches"
-          title={<>Parsed <span className="display italic text-muted-foreground">batches</span></>}
-          subtitle="Every 837P and 835 file the backend has ingested. Click a row for envelope, summary, and a peek at the contained claims."
-        />
+        {/* =================================================================
+            HERO — DARK EDITORIAL HEADER
+            ================================================================= */}
+        <section
+          className="relative pt-6 pb-8 lg:pt-9 lg:pb-10"
+          style={{ animationDelay: `${heroDelay}ms` }}
+        >
+          {/* Ghost "PARSED" watermark — a print-shop stamp behind the title. */}
+          <div
+            aria-hidden="true"
+            className="pointer-events-none select-none absolute inset-x-0 top-[58%] -translate-y-1/2 whitespace-nowrap display text-center"
+            style={{
+              fontSize: "clamp(160px, 20vw, 300px)",
+              letterSpacing: "-0.05em",
+              opacity: 0.05,
+              lineHeight: 1,
+              color: "hsl(var(--surface-ink))",
+            }}
+          >
+            PARSED
+          </div>
 
-        {isError ? (
-          <ErrorState
-            message="Couldn't load batches from the backend."
-            detail={error instanceof Error ? error.message : String(error)}
-            onRetry={() => refetch()}
+          <div className="relative z-10 grid grid-cols-1 lg:grid-cols-[1fr,auto] gap-8 items-end mb-7">
+            <div className="min-w-0 max-w-3xl">
+              <div className="flex items-center gap-3 mb-5">
+                <div className="h-px w-14 bg-foreground/25" />
+                <span className="mono text-[12px] uppercase tracking-[0.22em] text-muted-foreground">
+                  Batches · Register
+                </span>
+                <span
+                  className="mono text-[12px] uppercase tracking-[0.22em] text-muted-foreground/60 hidden sm:inline"
+                  aria-hidden
+                >
+                  · {totals.count} on file
+                </span>
+              </div>
+              <h1 className="display text-[48px] sm:text-[64px] lg:text-[80px] leading-[0.92] text-foreground tracking-[-0.04em]">
+                Parsed{" "}
+                <span className="italic text-muted-foreground/85">batches.</span>
+              </h1>
+            </div>
+            <div className="flex flex-col items-start lg:items-end gap-3">
+              <div className="inline-flex items-center gap-2 rounded-full border border-border/60 bg-card/60 px-3.5 py-2 text-[11.5px] mono uppercase tracking-[0.14em] text-muted-foreground backdrop-blur">
+                <Files
+                  className="h-3.5 w-3.5"
+                  strokeWidth={1.75}
+                  style={{ color: "hsl(var(--accent))" }}
+                />
+                837P · 835 · envelope & summary
+              </div>
+              <kbd
+                className="mono text-[10.5px] uppercase tracking-[0.18em] text-muted-foreground/70"
+              >
+                Tap a row to open the drawer
+              </kbd>
+            </div>
+          </div>
+
+          <div className="relative z-10 max-w-2xl">
+            <p className="text-[14px] text-muted-foreground leading-relaxed">
+              Every 837P and 835 file the backend has ingested. Click a row
+              for envelope, summary, and a peek at the contained claims.
+            </p>
+          </div>
+        </section>
+
+        {/* =================================================================
+            FOLD — TORN PAGE
+            ================================================================= */}
+        <div
+          aria-hidden
+          className="relative h-14"
+          style={{ animationDelay: `${foldDelay}ms` }}
+        >
+          <div
+            className="absolute inset-x-0 top-0 h-1/2"
+            style={{
+              background:
+                "linear-gradient(to bottom, hsl(0 0% 0% / 0.55), transparent)",
+            }}
           />
-        ) : null}
+          <div
+            className="absolute inset-x-0 bottom-0 h-1/2"
+            style={{
+              background:
+                "linear-gradient(to top, hsl(30 14% 14% / 0.18), transparent)",
+            }}
+          />
+          <div
+            className="absolute inset-x-0 top-1/2 -translate-y-1/2 h-px"
+            style={{
+              background:
+                "linear-gradient(to right, transparent, hsl(30 14% 14% / 0.5) 12%, hsl(30 14% 14% / 0.7) 50%, hsl(30 14% 14% / 0.5) 88%, transparent)",
+            }}
+          />
+          <div
+            className="absolute inset-x-0 top-1/2 -translate-y-1/2 flex justify-between px-2"
+            style={{ pointerEvents: "none" }}
+          >
+            {Array.from({ length: 48 }, (_, i) => (
+              <span
+                key={i}
+                className="block h-[3px] w-[3px] rounded-full"
+                style={{ backgroundColor: "hsl(30 14% 14% / 0.22)" }}
+              />
+            ))}
+          </div>
+          <div className="relative z-10 mx-auto h-full flex items-center justify-center gap-3 bg-background px-4 w-fit">
+            <span
+              className="display italic"
+              style={{ color: "hsl(var(--muted-foreground))", fontSize: 15 }}
+            >
+              ↘
+            </span>
+            <span
+              className="mono uppercase tracking-[0.24em]"
+              style={{
+                color: "hsl(var(--muted-foreground))",
+                fontSize: 11,
+                fontWeight: 500,
+              }}
+            >
+              The register
+            </span>
+            <span
+              className="display italic"
+              style={{ color: "hsl(var(--muted-foreground))", fontSize: 15 }}
+            >
+              ↙
+            </span>
+          </div>
+        </div>
 
-        <div className="surface rounded-xl overflow-hidden">
-          {isLoading ? (
-            <BatchesListSkeleton />
-          ) : items.length === 0 ? (
-            <EmptyState
-              eyebrow="Batches · awaiting first ingest"
-              message="Upload an 837P or 835 file on the Upload page to populate this list."
+        {/* =================================================================
+            PAPER PLANE
+            ================================================================= */}
+        <div
+          className="relative max-w-[1280px] mx-auto"
+          style={{
+            animationDelay: `${titleDelay}ms`,
+            backgroundColor: "hsl(var(--surface))",
+            boxShadow:
+              "inset 0 1px 0 0 hsl(0 0% 100% / 0.5), 0 1px 0 0 hsl(30 14% 22% / 0.06), 0 30px 80px -24px hsl(0 0% 0% / 0.45)",
+          }}
+        >
+          {/* Paper grain */}
+          <div
+            aria-hidden
+            className="pointer-events-none absolute inset-0 opacity-[0.04]"
+            style={{
+              backgroundImage:
+                "url(\"data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='160' height='160'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/><feColorMatrix values='0 0 0 0 0.1  0 0 0 0 0.08  0 0 0 0 0.05  0 0 0 0.9 0'/></filter><rect width='100%' height='100%' filter='url(%23n)'/></svg>\")",
+              backgroundSize: "160px 160px",
+              mixBlendMode: "multiply",
+            }}
+          />
+
+          {/* Title block */}
+          <div
+            className="relative px-8 lg:px-14 pt-12 pb-9 border-b animate-fade-in-up"
+            style={{
+              animationDelay: `${titleDelay}ms`,
+              borderColor: "hsl(30 14% 14% / 0.12)",
+            }}
+          >
+            <div
+              aria-hidden
+              className="absolute left-7 lg:left-12 top-0 bottom-0 w-px"
+              style={{ backgroundColor: "hsl(30 14% 14% / 0.14)" }}
             />
-          ) : (
-            <BatchesList items={items} openId={batchId} onOpen={open} />
-          )}
+            <div className="flex items-end justify-between gap-8 flex-wrap">
+              <div>
+                <div
+                  className="mono text-[12px] uppercase tracking-[0.24em] mb-4 font-medium"
+                  style={{ color: "hsl(var(--surface-ink-3))" }}
+                >
+                  Register · Parsed batches
+                </div>
+                <h2
+                  className="display leading-[0.92] tracking-[-0.04em]"
+                  style={{
+                    color: "hsl(var(--surface-ink))",
+                    fontSize: "clamp(48px, 7vw, 96px)",
+                    fontWeight: 400,
+                  }}
+                >
+                  The register.
+                </h2>
+                <div
+                  className="mt-4 display italic"
+                  style={{
+                    color: "hsl(var(--surface-ink-2))",
+                    fontSize: "clamp(15px, 1.3vw, 18px)",
+                    lineHeight: 1.4,
+                    maxWidth: "32ch",
+                  }}
+                >
+                  One row per ingested file — the kind, the input filename,
+                  how many claims it carried, and the day it was parsed.
+                </div>
+              </div>
+              <div className="text-right shrink-0">
+                <div
+                  className="mono text-[11px] uppercase tracking-[0.24em] mb-1.5 font-medium"
+                  style={{ color: "hsl(var(--surface-ink-3))" }}
+                >
+                  On file
+                </div>
+                <div
+                  className="display tabular-nums"
+                  style={{
+                    color: "hsl(var(--surface-ink))",
+                    fontSize: 26,
+                    lineHeight: 1.1,
+                  }}
+                >
+                  {totals.count}
+                </div>
+                <div
+                  className="mono text-[11px] mt-1"
+                  style={{ color: "hsl(var(--surface-ink-3))" }}
+                >
+                  batch{totals.count === 1 ? "" : "es"} · {totals.claims}{" "}
+                  claim{totals.claims === 1 ? "" : "s"}
+                </div>
+              </div>
+            </div>
+          </div>
+
+          {/* KPI strip — § 01 Vital signs */}
+          <section
+            aria-label="Batch register metrics"
+            className="relative px-8 lg:px-14 py-7 animate-fade-in-up"
+            style={{ animationDelay: `${kpiDelay}ms` }}
+          >
+            <div
+              aria-hidden
+              className="absolute left-7 lg:left-12 top-7 flex flex-col items-center gap-1"
+            >
+              <span
+                className="mono text-[10px] uppercase tracking-[0.18em] font-semibold"
+                style={{ color: "hsl(var(--surface-ink-3))" }}
+              >
+                § 01
+              </span>
+              <div
+                className="w-px h-10"
+                style={{ backgroundColor: "hsl(30 14% 14% / 0.18)" }}
+              />
+              <span
+                className="display italic"
+                style={{
+                  color: "hsl(var(--surface-ink-2))",
+                  fontSize: 11,
+                  writingMode: "vertical-rl",
+                  transform: "rotate(180deg)",
+                  letterSpacing: "0.16em",
+                }}
+              >
+                Vital signs
+              </span>
+            </div>
+            <div className="grid grid-cols-2 md:grid-cols-4 gap-4">
+              <BatchesKpiTile
+                label="On file"
+                value={totals.count}
+                icon={<Layers className="h-3 w-3" strokeWidth={1.75} />}
+                tone="ink"
+              />
+              <BatchesKpiTile
+                label="837P"
+                value={totals.p837}
+                icon={<GitBranch className="h-3 w-3" strokeWidth={1.75} />}
+                tone="blue"
+              />
+              <BatchesKpiTile
+                label="835"
+                value={totals.p835}
+                icon={<Receipt className="h-3 w-3" strokeWidth={1.75} />}
+                tone="amber"
+              />
+              <BatchesKpiTile
+                label="Claims"
+                value={totals.claims}
+                tone="success"
+              />
+            </div>
+          </section>
+
+          {/* Table — § 02 The register */}
+          <section
+            aria-label="Batch register"
+            className="relative px-8 lg:px-14 pb-8 lg:pb-10 animate-fade-in-up"
+            style={{ animationDelay: `${tableDelay}ms` }}
+          >
+            <div
+              aria-hidden
+              className="absolute left-7 lg:left-12 top-9 flex flex-col items-center gap-1"
+            >
+              <span
+                className="mono text-[10px] uppercase tracking-[0.18em] font-semibold"
+                style={{ color: "hsl(var(--surface-ink-3))" }}
+              >
+                § 02
+              </span>
+              <div
+                className="w-px h-12"
+                style={{ backgroundColor: "hsl(30 14% 14% / 0.18)" }}
+              />
+              <span
+                className="display italic"
+                style={{
+                  color: "hsl(var(--surface-ink-2))",
+                  fontSize: 11,
+                  writingMode: "vertical-rl",
+                  transform: "rotate(180deg)",
+                  letterSpacing: "0.16em",
+                }}
+              >
+                The register
+              </span>
+            </div>
+
+            <div
+              className="pt-6 border-t"
+              style={{
+                borderTopStyle: "double",
+                borderTopWidth: 3,
+                borderColor: "hsl(30 14% 14% / 0.12)",
+              }}
+            >
+              <div className="flex items-end justify-between gap-6 flex-wrap mb-5">
+                <div>
+                  <div
+                    className="mono text-[11.5px] uppercase tracking-[0.24em] font-semibold mb-2"
+                    style={{ color: "hsl(var(--surface-ink-3))" }}
+                  >
+                    The register
+                  </div>
+                  <h3
+                    className="display leading-[0.98] tracking-[-0.03em]"
+                    style={{
+                      color: "hsl(var(--surface-ink))",
+                      fontSize: "clamp(24px, 2.6vw, 32px)",
+                      fontWeight: 400,
+                    }}
+                  >
+                    All <span className="italic">ingests</span>, newest first.
+                  </h3>
+                </div>
+                <div
+                  className="text-[12.5px] display italic"
+                  style={{ color: "hsl(var(--surface-ink-2))", maxWidth: 380 }}
+                >
+                  Tap a row to open the envelope drawer. Use{" "}
+                  <kbd
+                    className="mono not-italic text-[10.5px] uppercase tracking-[0.14em] px-1 py-0.5 rounded-sm border"
+                    style={{
+                      borderColor: "hsl(30 14% 14% / 0.20)",
+                      color: "hsl(var(--surface-ink))",
+                    }}
+                  >
+                    ←
+                  </kbd>{" "}
+                  /{" "}
+                  <kbd
+                    className="mono not-italic text-[10.5px] uppercase tracking-[0.14em] px-1 py-0.5 rounded-sm border"
+                    style={{
+                      borderColor: "hsl(30 14% 14% / 0.20)",
+                      color: "hsl(var(--surface-ink))",
+                    }}
+                  >
+                    →
+                  </kbd>{" "}
+                  inside the drawer to step.
+                </div>
+              </div>
+
+              {isError ? (
+                <div
+                  className="rounded-md border p-5"
+                  style={{
+                    borderColor: "hsl(30 14% 14% / 0.16)",
+                    backgroundColor: "hsl(36 22% 96%)",
+                  }}
+                >
+                  <ErrorState
+                    message="Couldn't load batches from the backend."
+                    detail={error instanceof Error ? error.message : String(error)}
+                    onRetry={() => refetch()}
+                  />
+                </div>
+              ) : isLoading ? (
+                <div
+                  className="rounded-md border p-4 space-y-2"
+                  style={{
+                    borderColor: "hsl(30 14% 14% / 0.10)",
+                    backgroundColor: "hsl(36 22% 96%)",
+                  }}
+                >
+                  <BatchesListSkeleton />
+                </div>
+              ) : items.length === 0 ? (
+                <div
+                  className="rounded-md border p-10 text-center"
+                  style={{
+                    borderColor: "hsl(30 14% 14% / 0.16)",
+                    borderStyle: "dashed",
+                    backgroundColor: "hsl(36 22% 96%)",
+                  }}
+                >
+                  <EmptyState
+                    eyebrow="Batches · awaiting first ingest"
+                    message="Upload an 837P or 835 file on the Upload page to populate this list."
+                  />
+                </div>
+              ) : (
+                <div
+                  className="rounded-md border overflow-hidden"
+                  style={{
+                    borderColor: "hsl(30 14% 14% / 0.10)",
+                    backgroundColor: "hsl(36 22% 98%)",
+                    boxShadow:
+                      "inset 0 1px 0 0 hsl(0 0% 100% / 0.5)",
+                  }}
+                >
+                  <BatchesList
+                    items={items}
+                    openId={batchId}
+                    onOpen={open}
+                    tone="paper"
+                  />
+                </div>
+              )}
+            </div>
+          </section>
+
+          {/* Footer */}
+          <div
+            className="relative px-8 lg:px-14 py-5 border-t flex items-center justify-between mono text-[10.5px] uppercase tracking-[0.18em]"
+            style={{
+              borderColor: "hsl(30 14% 14% / 0.12)",
+              color: "hsl(var(--surface-ink-3))",
+            }}
+          >
+            <span>End of register</span>
+            <span>Cyclone · Batches</span>
+            <span>
+              {totals.count} {totals.count === 1 ? "row" : "rows"}
+            </span>
+          </div>
         </div>
       </div>
     </>
   );
 }
+
+// ---------------------------------------------------------------------------
+// BatchesKpiTile — paper-toned metric for the batch register.
+// Mirrors AckKpiTile / KpiTile in the other hybrid pages.
+// ---------------------------------------------------------------------------
+function BatchesKpiTile({
+  label,
+  value,
+  tone,
+  icon,
+}: {
+  label: string;
+  value: number;
+  tone: "blue" | "amber" | "ink" | "success";
+  icon?: React.ReactNode;
+}) {
+  const accentMap = {
+    blue: "hsl(212 100% 45%)",
+    amber: "hsl(36 92% 50%)",
+    ink: "hsl(var(--surface-ink))",
+    success: "hsl(152 64% 38%)",
+  } as const;
+  const tintMap = {
+    blue: "hsl(212 85% 92%)",
+    amber: "hsl(36 82% 92%)",
+    ink: "hsl(36 22% 90%)",
+    success: "hsl(152 50% 88%)",
+  } as const;
+  const accent = accentMap[tone];
+  const tint = tintMap[tone];
+  return (
+    <div
+      className="relative rounded-xl p-5 overflow-hidden border"
+      style={{
+        backgroundColor: "hsl(var(--surface))",
+        boxShadow:
+          "inset 0 1px 0 0 hsl(0 0% 100% / 0.45), 0 1px 0 0 hsl(30 14% 22% / 0.06), inset 3px 0 0 0 hsl(0 0% 100% / 0.4)",
+        borderColor: "hsl(30 14% 14% / 0.10)",
+      }}
+    >
+      <div
+        aria-hidden
+        className="absolute left-0 top-5 bottom-5 w-[3px] rounded-r-sm"
+        style={{ backgroundColor: accent, opacity: 0.85 }}
+      />
+      <div className="flex items-center justify-between mb-2.5">
+        <div
+          className="mono text-[10px] uppercase tracking-[0.18em] font-semibold"
+          style={{ color: "hsl(var(--surface-ink-3))" }}
+        >
+          {label}
+        </div>
+        <div
+          className="h-5 w-5 rounded-md flex items-center justify-center"
+          style={{ backgroundColor: tint, color: accent }}
+        >
+          {icon ?? (
+            <span
+              className="block h-1.5 w-1.5 rounded-full"
+              style={{ backgroundColor: accent }}
+            />
+          )}
+        </div>
+      </div>
+      <div
+        className="display tabular-nums tracking-[-0.04em]"
+        style={{
+          color: "hsl(var(--surface-ink))",
+          fontSize: "clamp(28px, 3vw, 40px)",
+          lineHeight: 1,
+          fontWeight: 400,
+        }}
+      >
+        {value}
+      </div>
+    </div>
+  );
+}

src/pages/Claims.test.tsx

@@ -8,6 +8,7 @@ import React, { act } from "react";
 import { createRoot, type Root } from "react-dom/client";
 import { describe, expect, it, vi, beforeEach, afterEach } from "vitest";
 import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
+import { MemoryRouter } from "react-router-dom";
 import { Claims } from "./Claims";
 import { api } from "@/lib/api";
 import { useTailStore } from "@/store/tail-store";
@@ -148,8 +149,30 @@ function setLocation(url: string): void {
  * a real DOM container wrapped in `QueryClientProvider` so the page's
  * TanStack Query calls (via `useClaims`) resolve against our mocked
  * `api.listClaims`.
+ *
+ * Also wraps in a `MemoryRouter` so the page's `useSearchParams`
+ * (added when Claims started reading `?status=` / `?sort=` off the URL
+ * for Dashboard KPI drill-through) has a router context to read from.
+ * The default `initialEntries` mirrors whatever `setLocation(...)` set
+ * on `window.location`, so the existing tests' pre-set URLs keep
+ * working without per-test changes.
  */
 function renderClaims(): { unmount: () => void } {
+  const initialEntries = [
+    window.location.pathname + window.location.search,
+  ];
+  return renderClaimsAt(initialEntries);
+}
+
+/**
+ * Variant of `renderClaims` that lets a test pin a specific initial
+ * URL. Used by the URL-param filter tests below so each one can start
+ * at exactly the URL it's asserting on.
+ */
+function renderClaimsAt(initialEntries: string[]): {
+  unmount: () => void;
+  container: HTMLDivElement;
+} {
   const container = document.createElement("div");
   document.body.appendChild(container);
   const qc = new QueryClient({
@@ -168,11 +191,16 @@ function renderClaims(): { unmount: () => void } {
       React.createElement(
         QueryClientProvider,
         { client: qc },
-        React.createElement(Claims)
-      )
+        React.createElement(
+          MemoryRouter,
+          { initialEntries },
+          React.createElement(Claims),
+        ),
+      ),
     );
   });
   return {
+    container,
     unmount: () => {
       act(() => root.unmount());
       container.remove();
@@ -531,4 +559,207 @@ describe("Claims page drawer wiring", () => {
 
     unmount();
   });
+
+  // -------------------------------------------------------------------
+  // URL-driven filter state (sub-project 6, Phase 1 Task 1.8 follow-up).
+  //
+  // Dashboard KPI tiles drill through to Claims with `?status=` and
+  // `?sort=` query params. These tests pin each URL and assert that
+  // the page actually filters (not just lands on a default view).
+  //
+  // The strongest assertion is on `api.listClaims.mock.calls` — that's
+  // the exact params the page forwards to the API, so a passing test
+  // proves end-to-end that URL → useSearchParams → useClaims → fetch.
+  // -------------------------------------------------------------------
+
+  it("test_url_param_status_denied_filters_and_selects_chip", async () => {
+    const { unmount, container } = renderClaimsAt(["/claims?status=denied"]);
+
+    // The first render of FilterChips is reached before useSearchParams
+    // has the URL-derived `status` value committed (MemoryRouter
+    // initializes synchronously but the chip's aria-checked only flips
+    // to "true" on the next React commit). Wait for that commit so
+    // the assertion below isn't a race against the first render.
+    // We settle on `useClaims` having been called with status=denied
+    // — that's the strongest invariant: it proves the URL → state →
+    // API-call chain has fully propagated end-to-end.
+    await settle(
+      () => {
+        const calls = (api.listClaims as ReturnType<typeof vi.fn>).mock.calls;
+        const lastCallParams = calls[calls.length - 1]?.[0] as
+          | { status?: string; sort?: string; order?: string }
+          | undefined;
+        return lastCallParams?.status === "denied";
+      },
+    );
+
+    // Scope queries to this test's container so we can't accidentally
+    // pick up a chip from a leaked render of a previous test.
+    const deniedChip = Array.from(
+      container.querySelectorAll('[role="radio"]'),
+    ).find(
+      (el) => el.textContent?.trim().toLowerCase() === "denied",
+    ) as HTMLButtonElement | undefined;
+    expect(deniedChip).toBeDefined();
+    expect(deniedChip?.getAttribute("aria-checked")).toBe("true");
+
+    // No other status chip should be checked.
+    const checkedChips = Array.from(
+      container.querySelectorAll('[role="radio"][aria-checked="true"]'),
+    );
+    expect(checkedChips).toHaveLength(1);
+    expect(checkedChips[0]?.textContent?.trim().toLowerCase()).toBe(
+      "denied",
+    );
+
+    unmount();
+  });
+
+  it("test_url_param_sort_minus_receivedAmount_sorts_by_received_desc", async () => {
+    const { unmount } = renderClaimsAt(["/claims?sort=-receivedAmount"]);
+
+    // Wait for useClaims to be called once.
+    await settle(
+      () => (api.listClaims as ReturnType<typeof vi.fn>).mock.calls.length > 0,
+    );
+
+    const calls = (api.listClaims as ReturnType<typeof vi.fn>).mock.calls;
+    const lastCallParams = calls[calls.length - 1]?.[0] as
+      | { status?: string; sort?: string; order?: string }
+      | undefined;
+
+    // The `-` prefix must be stripped off and order set to desc.
+    expect(lastCallParams?.sort).toBe("receivedAmount");
+    expect(lastCallParams?.order).toBe("desc");
+    // No status filter — user only asked for a sort change.
+    expect(lastCallParams?.status).toBeUndefined();
+
+    unmount();
+  });
+
+  it("test_url_param_sort_without_prefix_orders_ascending", async () => {
+    const { unmount } = renderClaimsAt(["/claims?sort=submittedDate"]);
+
+    await settle(
+      () => (api.listClaims as ReturnType<typeof vi.fn>).mock.calls.length > 0,
+    );
+
+    const calls = (api.listClaims as ReturnType<typeof vi.fn>).mock.calls;
+    const lastCallParams = calls[calls.length - 1]?.[0] as
+      | { status?: string; sort?: string; order?: string }
+      | undefined;
+
+    // No `-` prefix → order is asc.
+    expect(lastCallParams?.sort).toBe("submittedDate");
+    expect(lastCallParams?.order).toBe("asc");
+
+    unmount();
+  });
+
+  it("test_no_url_params_defaults_to_billed_desc_all_statuses", async () => {
+    // Default URL — matches the existing "click a row to open the
+    // drawer" tests, but here we assert on the params forwarded to
+    // the API to prove the no-param default matches the previous
+    // hardcoded behavior (sort=billedAmount, order=desc, no status).
+    const { unmount } = renderClaimsAt(["/claims"]);
+
+    await settle(
+      () => (api.listClaims as ReturnType<typeof vi.fn>).mock.calls.length > 0,
+    );
+
+    const calls = (api.listClaims as ReturnType<typeof vi.fn>).mock.calls;
+    const lastCallParams = calls[calls.length - 1]?.[0] as
+      | { status?: string; sort?: string; order?: string }
+      | undefined;
+
+    expect(lastCallParams?.status).toBeUndefined();
+    expect(lastCallParams?.sort).toBe("billedAmount");
+    expect(lastCallParams?.order).toBe("desc");
+
+    unmount();
+  });
+
+  it("test_url_param_sort_dash_only_falls_back_to_default", async () => {
+    // `?sort=-` is the prefix-with-no-field degenerate case. A naive
+    // `slice(1)` would yield "" and the API would get `sort=""`.
+    // We assert the page falls back to the default sort instead.
+    const { unmount } = renderClaimsAt(["/claims?sort=-"]);
+
+    await settle(
+      () => (api.listClaims as ReturnType<typeof vi.fn>).mock.calls.length > 0,
+    );
+
+    const calls = (api.listClaims as ReturnType<typeof vi.fn>).mock.calls;
+    const lastCallParams = calls[calls.length - 1]?.[0] as
+      | { status?: string; sort?: string; order?: string }
+      | undefined;
+
+    expect(lastCallParams?.sort).toBe("billedAmount");
+    expect(lastCallParams?.order).toBe("desc");
+
+    unmount();
+  });
+
+  // -------------------------------------------------------------------
+  // Regression for SP21 Task 2.4 — DrillableCell click bubbling.
+  //
+  // The provider cell renders a <button> (via DrillableCell) inside a
+  // <TableRow onClick={() => open(c.id)}>. Before the fix, clicking the
+  // provider button (1) navigated to /providers?provider=… and then
+  // (2) bubbled to the row, where open() rebuilt the URL on top of the
+  // new /providers URL and appended a phantom ?claim=CLM-1. The page
+  // mounted on /providers, but the URL was a Frankenstein of both
+  // nav states and the browser history was polluted with two entries
+  // per click.
+  //
+  // We assert the URL after a provider-cell click does NOT carry
+  // ?claim=. The fix lives in DrillableCell (stopPropagation), so this
+  // is an end-to-end check that the component-level guard closes the
+  // bubble all the way back at the row.
+  //
+  // Note on MemoryRouter: react-router's `navigate()` updates the
+  // router's internal history but does NOT push to window.history, so
+  // `window.location.href` in this test stays on `/claims`. That's
+  // still the right place to assert "no phantom claim= param landed on
+  // window.history" — that's where the bug manifested (buildUrl() in
+  // the row's open() reads window.location and pushState's the bad
+  // URL). In a real BrowserRouter the URL would advance to /providers
+  // after navigate(), and the same assertion holds: ?claim= would be
+  // absent.
+  // -------------------------------------------------------------------
+  it("test_clicking_provider_cell_navigates_without_pushing_claim_param", async () => {
+    const { unmount } = renderClaims();
+
+    // Wait for the table to populate from the mocked api.listClaims.
+    await settle(
+      () => document.body.textContent?.includes("CLM-1") ?? false,
+    );
+
+    // Both SAMPLE_CLAIMS use providerNpi "1234567890", which doesn't
+    // match any seeded sampleProvider, so the aria-label falls through
+    // to `View provider 1234567890`. Pick the first matching button.
+    const btn = Array.from(document.querySelectorAll("button")).find(
+      (b) =>
+        b.getAttribute("aria-label")?.startsWith("View provider ") ?? false,
+    ) as HTMLButtonElement | undefined;
+    expect(btn).toBeDefined();
+
+    // Sanity: row's claim-param is not in the URL before the click.
+    expect(window.location.href).not.toContain("claim=");
+
+    // Click it. With the fix, the click handler stops propagation before
+    // the row's onClick can fire. Without the fix, the row's open()
+    // would push a phantom ?claim=CLM-1 onto window.history.
+    await act(async () => {
+      btn!.click();
+    });
+
+    // The URL must not carry a ?claim= param. buildUrl() inside open()
+    // would have added that param if the click had bubbled to the row.
+    // (See the MemoryRouter note above for why we don't also assert
+    // on /providers here.)
+    expect(window.location.href).not.toContain("claim=");
+
+    unmount();
+  });
 });

src/pages/Claims.tsx

@@ -1,4 +1,5 @@
-import { useMemo, useRef, useState } from "react";
+import { useEffect, useMemo, useRef, useState } from "react";
+import { useNavigate, useSearchParams } from "react-router-dom";
 import { Search, X } from "lucide-react";
 import { Input } from "@/components/ui/input";
 import {
@@ -28,6 +29,7 @@ import { Pagination } from "@/components/ui/pagination";
 import { PageHeader } from "@/components/PageHeader";
 import { useClaims } from "@/hooks/useClaims";
 import { useDrawerUrlState } from "@/hooks/useDrawerUrlState";
+import { DrillableCell } from "@/components/drill/DrillableCell";
 import { useTailStream } from "@/hooks/useTailStream";
 import { useMergedTail } from "@/hooks/useMergedTail";
 import { TailStatusPill } from "@/components/TailStatusPill";
@@ -48,14 +50,81 @@ const STATUS_OPTIONS: FilterChipOption[] = [
   { value: "pending", label: "Pending" },
 ];
 
+// Whitelist of valid `?status=` values — anything else falls back to ALL.
+// Used both to validate the URL param on read AND to guard the Dropdown
+// onValueChange so the URL never carries a bogus value.
+const VALID_STATUSES: ReadonlySet<ClaimStatus> = new Set<ClaimStatus>([
+  "draft",
+  "submitted",
+  "accepted",
+  "denied",
+  "paid",
+  "pending",
+]);
+
 export function Claims() {
-  const [status, setStatus] = useState<ClaimStatus | typeof ALL>(ALL);
+  // -------------------------------------------------------------------------
+  // URL-driven filter state.
+  //
+  // The page reads `?status=` and `?sort=` off the URL (via React Router's
+  // useSearchParams) so deep links from the Dashboard KPI tiles — e.g.
+  // navigate("/claims?status=denied") — actually filter, not just land on
+  // a default view. Status and sort/order derive from the URL; pagination
+  // (`?page=`) and search (`?q=`) stay local because they're ephemeral
+  // view state that doesn't deserve a URL slot.
+  //
+  // Sort syntax: `?sort=billedAmount` → asc, `?sort=-billedAmount` → desc.
+  // The leading `-` is the conventional "negate" prefix used by most
+  // list APIs (incl. our own /api/claims), so we mirror it instead of
+  // using a separate `?order=` param.
+  // -------------------------------------------------------------------------
+  const [searchParams, setSearchParams] = useSearchParams();
+  const navigate = useNavigate();
+
+  const rawStatus = searchParams.get("status");
+  const status: ClaimStatus | typeof ALL =
+    rawStatus && VALID_STATUSES.has(rawStatus as ClaimStatus)
+      ? (rawStatus as ClaimStatus)
+      : ALL;
+
+  const rawSort = searchParams.get("sort");
+  let sort: string;
+  let order: "asc" | "desc";
+  if (rawSort && rawSort.length > 1 && rawSort.startsWith("-")) {
+    // Strip the `-` desc-marker, but only when there's an actual field
+    // after it. `?sort=-` (prefix only, no field) falls through to the
+    // default below — otherwise `slice(1)` would yield `""` and we'd
+    // hit the API with `sort=""`.
+    sort = rawSort.slice(1);
+    order = "desc";
+  } else if (rawSort && rawSort !== "-") {
+    sort = rawSort;
+    order = "asc";
+  } else {
+    // Default — match the previous hardcoded behavior so existing
+    // bookmarks and the "no params" path keep sorting by billed desc.
+    // Also catches `?sort=-` (no field after the prefix) and any other
+    // degenerate value.
+    sort = "billedAmount";
+    order = "desc";
+  }
+
   const [npi, setNpi] = useState<string>(ALL);
   const [query, setQuery] = useState("");
   const [page, setPage] = useState(1);
   const [helpOpen, setHelpOpen] = useState(false);
   const searchRef = useRef<HTMLInputElement>(null);
 
+  // Reset pagination whenever the URL-driven filters change. Without
+  // this, a deep link like `/claims?status=denied` lands on whatever
+  // page the user was last on (e.g. page 5 of an unfiltered list) and
+  // shows an empty view. Safe to run on every render of `status` or
+  // `sort` because `setPage(1)` is idempotent when already at 1, and
+  // changing `page` doesn't trigger this effect.
+  useEffect(() => {
+    setPage(1);
+  }, [status, sort]);
+
   const { claimId, open, close, setClaimId } = useDrawerUrlState();
 
   const providers = useAppStore((s) => s.providers);
@@ -64,11 +133,26 @@ export function Claims() {
     [providers]
   );
 
+  // Drop the `status` query param entirely when going back to "all", so
+  // the URL stays clean for sharing. Caller still owns `setPage(1)` to
+  // reset pagination.
+  const setStatus = (next: ClaimStatus | typeof ALL): void => {
+    setSearchParams(
+      (prev) => {
+        const params = new URLSearchParams(prev);
+        if (next === ALL) params.delete("status");
+        else params.set("status", next);
+        return params;
+      },
+      { replace: false },
+    );
+  };
+
   const params = {
     status: status === ALL ? undefined : status,
     provider_npi: npi === ALL ? undefined : npi,
-    sort: "billedAmount",
-    order: "desc" as const,
+    sort,
+    order,
     limit: PAGE_SIZE,
     offset: (page - 1) * PAGE_SIZE,
   };
@@ -284,10 +368,27 @@ export function Claims() {
                         </TableCell>
                         <TableCell className="font-medium text-[13px]">{c.patientName}</TableCell>
                         <TableCell>
-                          <div className="text-[13px]">{provider?.name ?? "Unknown"}</div>
-                          <div className="mono text-[10.5px] text-muted-foreground">
-                            {c.providerNpi}
-                          </div>
+                          <DrillableCell
+                            ariaLabel={`View provider ${provider?.name ?? c.providerNpi}`}
+                            onClick={() =>
+                              navigate(
+                                `/providers?provider=${encodeURIComponent(c.providerNpi)}`,
+                              )
+                            }
+                          >
+                            {/*
+                              DrillableCell renders an inline-flex button,
+                              so the two stacked lines would otherwise land
+                              side-by-side. The flex-col wrapper preserves
+                              the original "name on top, NPI below" layout.
+                            */}
+                            <div className="flex flex-col items-start">
+                              <div className="text-[13px]">{provider?.name ?? "Unknown"}</div>
+                              <div className="mono text-[10.5px] text-muted-foreground">
+                                {c.providerNpi}
+                              </div>
+                            </div>
+                          </DrillableCell>
                         </TableCell>
                         <TableCell className="text-muted-foreground text-[13px]">
                           {c.payerName}

src/pages/Dashboard.test.tsx

@@ -0,0 +1,151 @@
+// @vitest-environment happy-dom
+// SP21 Task 2.5: Dashboard "Recent activity" card routes clicks by event
+// kind. This test verifies the wiring end-to-end: a `claim_paid` event
+// in the activity slice becomes a clickable row that navigates to
+// `/claims?claim=<id>`, while a `remit_received` event surfaces a
+// "coming in a later phase" toast (since the RemitDrawer lands in
+// Phase 4).
+//
+// `Dashboard` reads `claims`, `providers`, `activity` from the
+// `useAppStore` slice, so we override the slice directly via
+// `useAppStore.setState` instead of mocking `useActivity` — the
+// sample-data mode is exactly what the dashboard sees when no API is
+// configured, so the test stays faithful to production behavior.
+(globalThis as { IS_REACT_ACT_ENVIRONMENT?: boolean }).IS_REACT_ACT_ENVIRONMENT = true;
+
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { cleanup, fireEvent, render } from "@testing-library/react";
+import { MemoryRouter } from "react-router-dom";
+import { Dashboard } from "./Dashboard";
+import { useAppStore } from "@/store";
+import type { Activity } from "@/types";
+
+// sonner renders toasts through a portal; jsdom has no layout so the
+// `position` style is a no-op. We just verify that `toast.info` is
+// called with the expected message — sonner itself has its own tests.
+vi.mock("sonner", () => ({
+  toast: {
+    info: vi.fn(),
+    success: vi.fn(),
+    error: vi.fn(),
+  },
+}));
+
+// Capture navigation side effects so we can assert on the URL the
+// Dashboard would push. We use a `MemoryRouter` (initialEntries=["/"])
+// and observe the rendered route via a tiny listener component that
+// reads the current `<MemoryRouter>` entry — no real `window.history`
+// or `BrowserRouter` required.
+import { useLocation } from "react-router-dom";
+
+function LocationProbe() {
+  const loc = useLocation();
+  return (
+    <div
+      data-testid="location"
+      data-pathname={loc.pathname}
+      data-search={loc.search}
+    />
+  );
+}
+
+afterEach(() => {
+  cleanup();
+  vi.clearAllMocks();
+  // Reset the activity slice so tests don't bleed into each other.
+  useAppStore.setState({ activity: [] });
+});
+
+describe("Dashboard · Recent activity event routing (SP21 Task 2.5)", () => {
+  it("navigates to /claims?claim=ID when a claim_paid event is clicked", () => {
+    const activity: Activity[] = [
+      {
+        id: "ae-1",
+        kind: "claim_paid",
+        message: "Paid CLM-42 · Jordan Smith",
+        timestamp: "2026-06-20T12:00:00Z",
+        claimId: "CLM-42",
+        remittanceId: null,
+      },
+    ];
+    useAppStore.setState({ activity });
+
+    const { getByTestId, getByRole } = render(
+      <MemoryRouter initialEntries={["/"]}>
+        <Dashboard />
+        <LocationProbe />
+      </MemoryRouter>,
+    );
+
+    // The row becomes a button-like <li> with role="button" and a
+    // descriptive aria-label derived from the kind.
+    const row = getByRole("button", { name: /View claim paid/ });
+    fireEvent.click(row);
+
+    const probe = getByTestId("location");
+    expect(probe.getAttribute("data-pathname")).toBe("/claims");
+    expect(probe.getAttribute("data-search")).toBe("?claim=CLM-42");
+  });
+
+  it("navigates to /providers?provider=NPI when a provider_added event is clicked", () => {
+    const activity: Activity[] = [
+      {
+        id: "ae-2",
+        kind: "provider_added",
+        message: "Added Cedar Park Family Medicine",
+        timestamp: "2026-06-20T12:00:00Z",
+        npi: "1730187395",
+        claimId: null,
+        remittanceId: null,
+      },
+    ];
+    useAppStore.setState({ activity });
+
+    const { getByTestId, getByRole } = render(
+      <MemoryRouter initialEntries={["/"]}>
+        <Dashboard />
+        <LocationProbe />
+      </MemoryRouter>,
+    );
+
+    fireEvent.click(getByRole("button", { name: /View provider added/ }));
+
+    const probe = getByTestId("location");
+    expect(probe.getAttribute("data-pathname")).toBe("/providers");
+    expect(probe.getAttribute("data-search")).toBe("?provider=1730187395");
+  });
+
+  it("fires the toast (no navigation) for remit_received — Phase 4 drawer", async () => {
+    const { toast } = await import("sonner");
+    const activity: Activity[] = [
+      {
+        id: "ae-3",
+        kind: "remit_received",
+        message: "Remit REM-7 received",
+        timestamp: "2026-06-20T12:00:00Z",
+        claimId: null,
+        remittanceId: "REM-7",
+      },
+    ];
+    useAppStore.setState({ activity });
+
+    const { getByTestId, getByRole } = render(
+      <MemoryRouter initialEntries={["/"]}>
+        <Dashboard />
+        <LocationProbe />
+      </MemoryRouter>,
+    );
+
+    fireEvent.click(getByRole("button", { name: /View remit received/ }));
+
+    expect(toast.info).toHaveBeenCalledTimes(1);
+    const msg = (toast.info as ReturnType<typeof vi.fn>).mock.calls[0]?.[0] as string;
+    expect(msg).toMatch(/remit received/i);
+    expect(msg).toMatch(/coming in a later phase/i);
+
+    // URL must not have changed — the toast path is non-navigating.
+    const probe = getByTestId("location");
+    expect(probe.getAttribute("data-pathname")).toBe("/");
+    expect(probe.getAttribute("data-search")).toBe("");
+  });
+});

src/pages/Dashboard.tsx

@@ -1,4 +1,5 @@
 import { useMemo } from "react";
+import { useNavigate } from "react-router-dom";
 import {
   AlertCircle,
   Banknote,
@@ -13,8 +14,11 @@ import { PageHeader } from "@/components/PageHeader";
 import { KpiCard } from "@/components/KpiCard";
 import { ActivityFeed } from "@/components/ActivityFeed";
 import { AnimatedNumber } from "@/components/AnimatedNumber";
+import { DrillableCell } from "@/components/drill/DrillableCell";
 import { fmt } from "@/lib/format";
+import { eventKindToUrl } from "@/lib/event-routing";
 import { useAppStore } from "@/store";
+import { toast } from "sonner";
 
 const MONTHS_BACK = 6;
 
@@ -70,6 +74,8 @@ export function Dashboard() {
   const providers = useAppStore((s) => s.providers);
   const activity = useAppStore((s) => s.activity);
 
+  const navigate = useNavigate();
+
   const kpis = useMemo(() => {
     const billed = claims.reduce((s, c) => s + c.billedAmount, 0);
     const received = claims.reduce((s, c) => s + c.receivedAmount, 0);
@@ -162,67 +168,92 @@ export function Dashboard() {
         aria-label="Key performance indicators"
         className="grid gap-3.5 grid-cols-1 sm:grid-cols-2 md:grid-cols-3 lg:grid-cols-5"
       >
-        <KpiCard
-          label="Claims"
-          icon={Receipt}
-          sparkline={monthly.count}
-          className="animate-fade-in-up"
-          style={{ animationDelay: `${kpiBase + 0 * kpiStep}ms` }}
-          value={
-            <AnimatedNumber value={kpis.count} format={(n) => fmt.num(Math.round(n))} />
-          }
-          hint="last 6 months"
-        />
-        <KpiCard
-          label="Billed"
-          icon={CircleDollarSign}
-          accent="accent"
-          sparkline={monthly.billed}
-          className="animate-fade-in-up"
-          style={{ animationDelay: `${kpiBase + 1 * kpiStep}ms` }}
-          value={<AnimatedNumber value={kpis.billed} format={fmt.usd} />}
-          delta={{ value: "+12.4%", direction: "up", positive: true }}
-        />
-        <KpiCard
-          label="Received"
-          icon={Banknote}
-          accent="success"
-          sparkline={monthly.received}
-          className="animate-fade-in-up"
-          style={{ animationDelay: `${kpiBase + 2 * kpiStep}ms` }}
-          value={<AnimatedNumber value={kpis.received} format={fmt.usd} />}
-          delta={{ value: "+8.1%", direction: "up", positive: true }}
-        />
-        <KpiCard
-          label="Pending AR"
-          icon={Clock}
-          accent="warning"
-          sparkline={monthly.ar}
-          className="animate-fade-in-up"
-          style={{ animationDelay: `${kpiBase + 3 * kpiStep}ms` }}
-          value={
-            <AnimatedNumber
-              value={kpis.outstandingAr}
-              format={(n) => fmt.usd(Math.max(0, n))}
-            />
-          }
-          hint={`${kpis.pending} in queue`}
-        />
-        <KpiCard
-          label="Denial rate"
-          icon={TrendingDown}
-          accent="destructive"
-          sparkline={monthly.denialRate}
-          className="animate-fade-in-up"
-          style={{ animationDelay: `${kpiBase + 4 * kpiStep}ms` }}
-          value={
-            <AnimatedNumber
-              value={kpis.denialRate}
-              format={(n) => fmt.pct(n)}
-            />
-          }
-          delta={{ value: "-1.2 pts", direction: "down", positive: true }}
-        />
+        <DrillableCell
+          onClick={() => navigate("/claims")}
+          ariaLabel="View all claims"
+        >
+          <KpiCard
+            label="Claims"
+            icon={Receipt}
+            sparkline={monthly.count}
+            className="animate-fade-in-up"
+            style={{ animationDelay: `${kpiBase + 0 * kpiStep}ms` }}
+            value={
+              <AnimatedNumber value={kpis.count} format={(n) => fmt.num(Math.round(n))} />
+            }
+            hint="last 6 months"
+          />
+        </DrillableCell>
+        <DrillableCell
+          onClick={() => navigate("/claims?sort=-billedAmount")}
+          ariaLabel="View claims sorted by billed amount"
+        >
+          <KpiCard
+            label="Billed"
+            icon={CircleDollarSign}
+            accent="accent"
+            sparkline={monthly.billed}
+            className="animate-fade-in-up"
+            style={{ animationDelay: `${kpiBase + 1 * kpiStep}ms` }}
+            value={<AnimatedNumber value={kpis.billed} format={fmt.usd} />}
+            delta={{ value: "+12.4%", direction: "up", positive: true }}
+          />
+        </DrillableCell>
+        <DrillableCell
+          onClick={() => navigate("/claims?sort=-receivedAmount")}
+          ariaLabel="View claims sorted by received amount"
+        >
+          <KpiCard
+            label="Received"
+            icon={Banknote}
+            accent="success"
+            sparkline={monthly.received}
+            className="animate-fade-in-up"
+            style={{ animationDelay: `${kpiBase + 2 * kpiStep}ms` }}
+            value={<AnimatedNumber value={kpis.received} format={fmt.usd} />}
+            delta={{ value: "+8.1%", direction: "up", positive: true }}
+          />
+        </DrillableCell>
+        <DrillableCell
+          onClick={() => navigate("/claims")}
+          ariaLabel="View pending accounts receivable claims"
+        >
+          <KpiCard
+            label="Pending AR"
+            icon={Clock}
+            accent="warning"
+            sparkline={monthly.ar}
+            className="animate-fade-in-up"
+            style={{ animationDelay: `${kpiBase + 3 * kpiStep}ms` }}
+            value={
+              <AnimatedNumber
+                value={kpis.outstandingAr}
+                format={(n) => fmt.usd(Math.max(0, n))}
+              />
+            }
+            hint={`${kpis.pending} in queue`}
+          />
+        </DrillableCell>
+        <DrillableCell
+          onClick={() => navigate("/claims?status=denied")}
+          ariaLabel="View denied claims"
+        >
+          <KpiCard
+            label="Denial rate"
+            icon={TrendingDown}
+            accent="destructive"
+            sparkline={monthly.denialRate}
+            className="animate-fade-in-up"
+            style={{ animationDelay: `${kpiBase + 4 * kpiStep}ms` }}
+            value={
+              <AnimatedNumber
+                value={kpis.denialRate}
+                format={(n) => fmt.pct(n)}
+              />
+            }
+            delta={{ value: "-1.2 pts", direction: "down", positive: true }}
+          />
+        </DrillableCell>
       </section>
 
       {/* Activity + Top providers */}
@@ -246,7 +277,24 @@ export function Dashboard() {
             </span>
           </CardHeader>
           <CardContent className="pt-0">
-            <ActivityFeed items={activity.slice(0, 10)} />
+            <ActivityFeed
+              items={activity.slice(0, 10)}
+              onItemClick={(evt) => {
+                // SP21 Task 2.5: route by event kind. claim_* kinds
+                // navigate to the matching claim drawer (URL-driven,
+                // drawer mounts in Phase 5); provider_added opens the
+                // ProviderDrawer. remit_received and any unmapped
+                // kind surface a "coming soon" toast so the click
+                // still gives feedback until the RemitDrawer lands in
+                // Phase 4.
+                const url = eventKindToUrl(evt);
+                if (url) navigate(url);
+                else
+                  toast.info(
+                    `Drill for ${evt.kind.replace(/_/g, " ")} coming in a later phase.`,
+                  );
+              }}
+            />
           </CardContent>
         </Card>
 
@@ -260,7 +308,22 @@ export function Dashboard() {
           <CardContent className="pt-0">
             <ul className="space-y-4">
               {topProviders.map((p, i) => (
-                <li key={p.npi} className="flex items-center gap-3">
+                <li
+                  key={p.npi}
+                  onClick={() =>
+                    navigate(`/providers?provider=${encodeURIComponent(p.npi)}`)
+                  }
+                  onKeyDown={(e) => {
+                    if (e.key === "Enter")
+                      navigate(
+                        `/providers?provider=${encodeURIComponent(p.npi)}`
+                      );
+                  }}
+                  role="button"
+                  tabIndex={0}
+                  aria-label={`View provider ${p.name}`}
+                  className="drillable flex items-center gap-3"
+                >
                   <div className="h-7 w-7 rounded-md bg-muted/60 ring-1 ring-inset ring-border/40 flex items-center justify-center mono text-[10.5px] text-muted-foreground">
                     {String(i + 1).padStart(2, "0")}
                   </div>
@@ -306,7 +369,14 @@ export function Dashboard() {
                 {topDenials.map((c) => (
                   <li
                     key={c.id}
-                    className="flex items-start gap-3 py-3 first:pt-0 last:pb-0"
+                    onClick={() => navigate(`/claims?claim=${encodeURIComponent(c.id)}`)}
+                    onKeyDown={(e) => {
+                      if (e.key === "Enter") navigate(`/claims?claim=${encodeURIComponent(c.id)}`);
+                    }}
+                    role="button"
+                    tabIndex={0}
+                    aria-label={`View claim ${c.id}`}
+                    className="drillable flex items-start gap-3 py-3 first:pt-0 last:pb-0"
                   >
                     <div className="display mono text-[12.5px] text-muted-foreground pt-0.5 w-24 shrink-0">
                       {c.id}

src/pages/Inbox.tsx

@@ -13,6 +13,7 @@
 // ---------------------------------------------------------------------------
 
 import { useState } from "react";
+import { cn } from "@/lib/utils";
 import { Lane, type LaneRow } from "@/components/inbox/Lane";
 import { InboxHeader } from "@/components/inbox/InboxHeader";
 import { BulkBar } from "@/components/inbox/BulkBar";
@@ -160,15 +161,21 @@ export default function Inbox() {
   if (loading) {
     return (
       <div
-        className="min-h-screen p-8 mono flex items-center gap-2"
-        style={{ background: "var(--tt-bg)", color: "var(--tt-ink-dim)", fontSize: 12 }}
+        className="min-h-screen"
+        style={{ background: "var(--tt-bg)", color: "var(--tt-ink)" }}
       >
-        <span
-          aria-hidden
-          className="inline-block h-1.5 w-1.5 rounded-full animate-pulse-dot"
-          style={{ background: "var(--tt-amber)" }}
-        />
-        loading inbox…
+        <InboxHeader needEyesCount={0} doneTodayCount={0} />
+        <div
+          className="px-6 lg:px-10 py-10 mono flex items-center gap-2"
+          style={{ color: "var(--tt-ink-dim)", fontSize: 12 }}
+        >
+          <span
+            aria-hidden
+            className="inline-block h-1.5 w-1.5 rounded-full animate-pulse-dot"
+            style={{ background: "var(--tt-amber)" }}
+          />
+          loading inbox…
+        </div>
       </div>
     );
   }
@@ -176,13 +183,22 @@ export default function Inbox() {
   if (error) {
     return (
       <div
-        className="min-h-screen p-8 mono flex flex-col gap-2"
-        style={{ background: "var(--tt-bg)", color: "var(--tt-oxblood)", fontSize: 12 }}
+        className="min-h-screen"
+        style={{ background: "var(--tt-bg)", color: "var(--tt-ink)" }}
       >
-        <span className="uppercase tracking-[0.18em]" style={{ fontSize: 10, fontWeight: 700 }}>
-          Connection error
-        </span>
-        <span>{error.message}</span>
+        <InboxHeader needEyesCount={0} doneTodayCount={0} />
+        <div
+          className="px-6 lg:px-10 py-10 mono flex flex-col gap-2"
+          style={{ color: "var(--tt-oxblood)", fontSize: 12 }}
+        >
+          <span
+            className="uppercase tracking-[0.18em]"
+            style={{ fontSize: 10, fontWeight: 700 }}
+          >
+            Connection error
+          </span>
+          <span>{error.message}</span>
+        </div>
       </div>
     );
   }
@@ -203,7 +219,53 @@ export default function Inbox() {
       style={{ background: "var(--tt-bg)", color: "var(--tt-ink)" }}
     >
       <InboxHeader needEyesCount={needEyes} doneTodayCount={lanes.done_today.length} />
-      <main className="px-6 pb-24 pt-4 flex gap-4 items-stretch flex-wrap">
+
+      {/* Fold — a thin amber rule + italic serif annotation that
+          transitions the editorial header into the lane grid below. */}
+      <div
+        aria-hidden
+        className="relative h-10 flex items-center"
+        style={{ background: "var(--tt-bg)" }}
+      >
+        <div
+          className="absolute inset-x-0 top-1/2 -translate-y-1/2 h-px"
+          style={{
+            background:
+              "linear-gradient(to right, transparent, var(--tt-amber) 12%, var(--tt-amber) 88%, transparent)",
+            opacity: 0.35,
+          }}
+        />
+        <div
+          className="relative z-10 mx-auto px-3 flex items-center gap-2"
+          style={{ background: "var(--tt-bg)" }}
+        >
+          <span
+            className="display italic"
+            style={{ color: "var(--tt-amber)", fontSize: 14 }}
+          >
+            ↘
+          </span>
+          <span
+            className="mono uppercase"
+            style={{
+              color: "var(--tt-ink-dim)",
+              fontSize: 10.5,
+              letterSpacing: "0.24em",
+              fontWeight: 500,
+            }}
+          >
+            Five lanes · one queue
+          </span>
+          <span
+            className="display italic"
+            style={{ color: "var(--tt-amber)", fontSize: 14 }}
+          >
+            ↙
+          </span>
+        </div>
+      </div>
+
+      <main className="px-6 lg:px-10 pb-24 pt-4 flex gap-4 items-stretch flex-wrap">
         <Lane
           name="REJECTED"
           accent="oxblood"
@@ -247,6 +309,103 @@ export default function Inbox() {
         />
       </main>
 
+      {/* ----------------------------------------------------------------
+          PAPER-TONED SUMMARY STRIP
+          A cream "ledger" panel below the lanes that shows the aggregate
+          eye-flow across the queue. Mirrors the "Magazine Spread" pattern
+          used on the Dashboard/Claims/etc pages so the Inbox feels part
+          of the same document set, not a stand-alone terminal.
+          ---------------------------------------------------------------- */}
+      <section
+        aria-label="Queue summary"
+        className="relative mx-6 lg:mx-10 mt-6 mb-4"
+      >
+        <div
+          className="relative rounded-xl overflow-hidden border"
+          style={{
+            backgroundColor: "hsl(var(--surface))",
+            borderColor: "hsl(30 14% 14% / 0.10)",
+            boxShadow:
+              "inset 0 1px 0 0 hsl(0 0% 100% / 0.5), 0 1px 0 0 hsl(30 14% 22% / 0.06), 0 12px 40px -16px hsl(0 0% 0% / 0.45)",
+          }}
+        >
+          {/* Title row */}
+          <div
+            className="px-5 lg:px-7 py-4 border-b flex items-center justify-between gap-4 flex-wrap"
+            style={{ borderColor: "hsl(30 14% 14% / 0.10)" }}
+          >
+            <div>
+              <div
+                className="mono text-[10.5px] uppercase tracking-[0.20em] font-semibold mb-1.5"
+                style={{ color: "hsl(var(--surface-ink-3))" }}
+              >
+                Queue ledger
+              </div>
+              <h2
+                className="display leading-[0.95] tracking-[-0.03em]"
+                style={{
+                  color: "hsl(var(--surface-ink))",
+                  fontSize: "clamp(22px, 2.2vw, 28px)",
+                  fontWeight: 400,
+                }}
+              >
+                The eye-flow, <span className="italic">at a glance.</span>
+              </h2>
+            </div>
+            <div
+              className="text-right"
+              aria-label="Aggregate metrics"
+            >
+              <div
+                className="mono text-[10px] uppercase tracking-[0.18em] font-semibold"
+                style={{ color: "hsl(var(--surface-ink-3))" }}
+              >
+                Need eyes
+              </div>
+              <div
+                className="display tabular-nums"
+                style={{
+                  color: "hsl(var(--surface-ink))",
+                  fontSize: 24,
+                  lineHeight: 1.1,
+                }}
+              >
+                {needEyes}
+              </div>
+            </div>
+          </div>
+
+          {/* Lane metrics row — paper tiles that mirror each lane's accent */}
+          <div className="grid grid-cols-2 lg:grid-cols-5 divide-x divide-y lg:divide-y-0" style={{ borderColor: "hsl(30 14% 14% / 0.08)" }}>
+            <SummaryTile
+              label="Rejected"
+              value={lanes.rejected.length}
+              tone="oxblood"
+            />
+            <SummaryTile
+              label="Payer rejected"
+              value={lanes.payer_rejected.length}
+              tone="oxblood"
+            />
+            <SummaryTile
+              label="Candidates"
+              value={lanes.candidates.length}
+              tone="amber"
+            />
+            <SummaryTile
+              label="Unmatched"
+              value={lanes.unmatched.length}
+              tone="ink"
+            />
+            <SummaryTile
+              label="Done today"
+              value={lanes.done_today.length}
+              tone="muted"
+            />
+          </div>
+        </div>
+      </section>
+
       {/* Per-lane bulk bars. Each shows when its lane has a selection. */}
       <BulkBar
         lane="rejected"
@@ -307,7 +466,7 @@ export default function Inbox() {
               borderColor: "var(--tt-amber)",
               color: "var(--tt-ink)",
               boxShadow:
-                "0 0 0 1px hsl(36 88% 56% / 0.18), 0 24px 60px -12px hsl(0 0% 0% / 0.7), inset 0 1px 0 0 hsl(0 0% 100% / 0.04)",
+                "0 0 0 1px hsl(36 75% 58% / 0.18), 0 24px 60px -12px hsl(0 0% 0% / 0.5), inset 0 1px 0 0 hsl(0 0% 100% / 0.03)",
             }}
           >
             <div className="flex items-center gap-2 mb-3">
@@ -404,3 +563,87 @@ export default function Inbox() {
     </div>
   );
 }
+
+// ---------------------------------------------------------------------------
+// SummaryTile — paper-toned metric for the queue ledger strip. Mirrors
+// the lane accent (oxblood / amber / ink-blue / muted) so the eye-flow
+// reads at a glance.
+// ---------------------------------------------------------------------------
+const SUMMARY_ACCENTS: Record<
+  "oxblood" | "amber" | "ink" | "muted",
+  { dot: string; tint: string; text: string }
+> = {
+  oxblood: {
+    dot: "hsl(358 70% 42%)",
+    tint: "hsl(358 70% 92%)",
+    text: "hsl(358 70% 30%)",
+  },
+  amber: {
+    dot: "hsl(36 92% 50%)",
+    tint: "hsl(36 82% 88%)",
+    text: "hsl(36 92% 30%)",
+  },
+  ink: {
+    dot: "hsl(212 80% 45%)",
+    tint: "hsl(212 85% 92%)",
+    text: "hsl(212 80% 30%)",
+  },
+  muted: {
+    dot: "hsl(30 8% 50%)",
+    tint: "hsl(36 22% 90%)",
+    text: "hsl(30 8% 30%)",
+  },
+};
+
+function SummaryTile({
+  label,
+  value,
+  tone,
+}: {
+  label: string;
+  value: number;
+  tone: "oxblood" | "amber" | "ink" | "muted";
+}) {
+  const a = SUMMARY_ACCENTS[tone];
+  return (
+    <div
+      className={cn(
+        "relative px-4 py-4 first:pl-5 lg:first:pl-7 last:pr-5 lg:last:pr-7"
+      )}
+    >
+      <div className="flex items-center gap-2 mb-2">
+        <span
+          aria-hidden
+          className="block h-1.5 w-1.5 rounded-full"
+          style={{ backgroundColor: a.dot }}
+        />
+        <span
+          className="mono text-[10px] uppercase tracking-[0.20em] font-semibold"
+          style={{ color: "hsl(var(--surface-ink-3))" }}
+        >
+          {label}
+        </span>
+      </div>
+      <div
+        className="display tabular-nums tracking-[-0.03em]"
+        style={{
+          color: "hsl(var(--surface-ink))",
+          fontSize: "clamp(24px, 2vw, 30px)",
+          lineHeight: 1,
+          fontWeight: 400,
+        }}
+      >
+        {value}
+      </div>
+      <div
+        className="mono text-[10px] uppercase tracking-[0.16em] mt-1.5 inline-flex items-center gap-1 px-1.5 py-0.5 rounded-sm"
+        style={{
+          color: a.text,
+          backgroundColor: a.tint,
+        }}
+      >
+        {value === 0 ? "Clear" : value === 1 ? "row" : "rows"}
+      </div>
+    </div>
+  );
+}

src/pages/Providers.tsx

@@ -3,12 +3,15 @@ import { Skeleton } from "@/components/ui/skeleton";
 import { EmptyState } from "@/components/ui/empty-state";
 import { ErrorState } from "@/components/ui/error-state";
 import { PageHeader } from "@/components/PageHeader";
+import { ProviderDrawer } from "@/components/ProviderDrawer";
+import { useProviderDrawerUrlState } from "@/hooks/useProviderDrawerUrlState";
 import { useProviders } from "@/hooks/useProviders";
 import { fmt } from "@/lib/format";
 
 export function Providers() {
   const { data, isLoading, isError, error, refetch } = useProviders();
   const items = data?.items ?? [];
+  const { providerNpi, open, close } = useProviderDrawerUrlState();
 
   return (
     <div className="space-y-6 lg:space-y-8 animate-fade-in">
@@ -44,7 +47,14 @@ export function Providers() {
           {items.map((p) => (
             <article
               key={p.npi}
-              className="group surface-2 rounded-xl p-5 flex flex-col gap-4 transition-colors hover:bg-muted/20 cursor-default"
+              onClick={() => open(p.npi)}
+              onKeyDown={(e) => {
+                if (e.key === "Enter") open(p.npi);
+              }}
+              role="button"
+              tabIndex={0}
+              aria-label={`View provider ${p.name}`}
+              className="group drillable surface-2 rounded-xl p-5 flex flex-col gap-4 transition-colors hover:bg-muted/20 cursor-pointer"
             >
               <div className="flex items-start gap-3">
                 <div className="h-10 w-10 rounded-md bg-muted/60 ring-1 ring-inset ring-border/40 flex items-center justify-center text-foreground">
@@ -91,6 +101,8 @@ export function Providers() {
           ))}
         </div>
       )}
+
+      <ProviderDrawer npi={providerNpi} onClose={close} />
     </div>
   );
 }

src/store/index.ts

@@ -49,6 +49,10 @@ export const useAppStore = create<AppState>((set) => ({
           timestamp: claim.submissionDate,
           npi: claim.providerNpi,
           amount: claim.billedAmount,
+          // SP21 Task 2.5: mirror the backend wire shape so the
+          // Dashboard routing helper finds the claim id.
+          claimId: claim.id,
+          remittanceId: null,
         },
         ...s.activity,
       ],

src/types/index.ts

@@ -50,6 +50,58 @@ export interface Provider {
   phone: string;
   claimCount: number;
   outstandingAr: number;
+  /**
+   * SP21 Task 1.6: populated by the extended `GET /api/config/providers/{npi}`
+   * endpoint. Top 10 claims for this provider by `submissionDate` desc.
+   * Optional so legacy callers (in-memory sample data) keep working
+   * without an API round-trip.
+   */
+  recent_claims?: ClaimSummary[];
+  /**
+   * SP21 Task 1.6: populated by the extended `GET /api/config/providers/{npi}`
+   * endpoint. Top 10 activity events (by `ts` desc) joined to claims
+   * owned by this provider via `claim_id`.
+   */
+  recent_activity?: ActivityEvent[];
+}
+
+/**
+ * SP21 Task 1.6: slim claim projection returned by
+ * `GET /api/config/providers/{npi}.recent_claims`. Mirrors the wire
+ * shape of `store.iter_claims(provider_npi=...)` 1:1 (camelCase,
+ * superset of the legacy `Claim` interface).
+ */
+export interface ClaimSummary {
+  id: string;
+  state: string;
+  billedAmount: number;
+  patientName: string;
+  providerNpi: string;
+  payerName: string;
+  cptCode: string;
+  submissionDate: string;
+  parsedAt: string;
+  status: string;
+  matchedRemittanceId?: string | null;
+  batchId: string;
+  receivedAmount?: number;
+  denialReason?: string | null;
+}
+
+/**
+ * SP21 Task 1.6: one row in `recent_activity`. Mirrors the Python
+ * ORM `ActivityEvent` (snake_case fields rewritten to camelCase for
+ * the wire). `payload` carries the same dict the recorder wrote at
+ * the time of the event (message, npi, amount, etc.).
+ */
+export interface ActivityEvent {
+  id: number;
+  ts: string; // ISO Z
+  kind: string;
+  batchId: string | null;
+  claimId: string | null;
+  remittanceId: string | null;
+  payload: Record<string, unknown>;
 }
 
 export interface Remittance {
@@ -103,6 +155,23 @@ export interface Activity {
   timestamp: string;
   npi?: string;
   amount?: number;
+  /**
+   * SP21 Task 2.5: read from the backend `ActivityEvent.claim_id` so
+   * the Dashboard "Recent activity" card can route a click on a
+   * `claim_*` event to the matching claim drawer (via
+   * `src/lib/event-routing.ts`). Populated only for events that
+   * correspond to a specific claim; `null` for orphan events such as
+   * `remit_received` or `provider_added`.
+   */
+  claimId?: string | null;
+  /**
+   * SP21 Task 2.5: read from the backend `ActivityEvent.remittance_id`.
+   * Populated only for events that reference a specific remittance
+   * (e.g. `remit_received`); `null` otherwise. The Dashboard toast
+   * covers the Phase 2 case where this routes to a not-yet-built
+   * `RemitDrawer` (Phase 4).
+   */
+  remittanceId?: string | null;
 }
 
 // ---------------------------------------------------------------------------