phase: 100_page_width_consistency

**Phase 100 — final verification pass: all green.**

- Verified the shipped CSS contract directly: `--chat-column: 72rem` in `:root`; 0 literal `max-width: 46rem`; no `@media (min-width: 1500px)` block; exactly 4 token-capped reading columns; tuning/theme/doc-edit shells cap-free, structurally `.sources-shell`; `mock_llm.py` diff is comment-only.
- Defect found & fixed (phase-93 suite): `test_theme_semantic_completion.py::test_reset_removes_tag_byte_identical` raced theme.js's post-PUT refetch — it asserted the `#bor-theme` tag was gone right after the result line, but tag removal lands in the reconcile after the re-fetch (failed ~1 in 5 runs after `test_chat_rag`, reproduced). Fixed with an auto-waiting `expect(...).to_have_count(0)` (settled-state wait, the file's existing house pattern). 6/6 clean on the repro loop after.
- Tests/lint/coverage: `uv run pytest --cov=app --cov-report=term-missing` → 2052 passed, **99%** on `app/`; `uv run ruff check .` + `uv run pyright` → 0 errors.
- E2E in isolation (all passed): `test_wide_desktop_column.py` 3 (the phase suite — chat==tuning==theme==RAG ±4px at 1280 & 1920, ≈1152px; shared ≈1152px; standalone doc ≈1112px; modal unchanged ≈1100px; 360px overflow-free), `test_ui_customization` 4, `test_admin_theme_tab` 5, `test_document_viewer` 7, `test_save_share_ux` 5, `test_sticky_navbar` 3, `test_markdown_tables` 6, `test_responsive_polish` 7, `test_chat_rag` 3, `test_theme_semantic_completion` 8.
- Completion criteria: ① measured 72rem everywhere (≥~1200px, ±4px) + full-width below + 360px clean — **PASS** (E2E); ② zero 46rem rules / no 1500px block / four token selectors — **PASS** (grep + unit pins); ③ B4 byte-identical no-op + mobile squeeze — **PASS** (theme + responsive suites green); ④ full suite / coverage / lint — **PASS**; ⑤ atomic commit — left to the harness per executor protocol (all changes in the working tree, uncommitted).
- Deviations: none from phase decisions; only change in this pass is the race fix above (test-only, behavior unchanged).
- Next pending phase: `98_sync_summary_visibility` (numeric order in `todo/`; also pending: 99, 101–105).

tests/e2e/test_document_viewer.py

@@ -24,7 +24,9 @@ Test → story mapping (Playwright Mapping Rule):
    renders as escaped text; no dialog fires.
 6. ``test_standalone_page_still_works`` — the dedicated ``/document.html``
    page keeps its phase-10 contract (title/content/badges, not-found,
-   dark theme, no-CDN, a11y frame, ≤736px md column).
+   dark theme, no-CDN, a11y frame, the 72rem-container md column —
+   phase 100: ≈1112px at the 1280px fixture viewport, the container's
+   inner content).
 7. ``test_modal_theme_and_no_cdn`` — dark page background, the panel on
    the Phase-08 surface colour, every asset same-origin or ``data:``.
 """
@@ -406,9 +408,16 @@ def test_standalone_page_still_works(
     expect(page.locator(".doc-shell")).to_have_attribute("aria-live", "polite")
     assert page.evaluate("() => document.activeElement && document.activeElement.id") == "main"
 
-    # Markdown column centered and capped at 46rem (736px at 16px root).
+    # Markdown column: the 72rem container's inner content (phase 100 —
+    # the 46rem cap and its wide-desktop doubling are retired): at the
+    # 1280px fixture viewport the container is 1152px border-box, so
+    # .doc-md (width:100% inside it) measures 1152 − 2×1.25rem = 1112px.
     box = page.locator("#doc-content .doc-md").bounding_box()
-    assert box is not None and box["width"] <= 736 + 1
+    assert box is not None, "the standalone .doc-md column is not rendered"
+    assert abs(box["width"] - 1112) <= 4, (
+        f"the standalone .doc-md column is {box['width']:.0f}px, "
+        f"want 1112px (the 72rem container's inner content) ±4px"
+    )
 
     assert errors == [], f"console crashes: {errors}"