# Phase 100 — Every page matches the RAG page's width (the 72rem container, at every viewport)

**Source:** Owner request (chat, 2026-09-12) — "The theme, tuning, and chat pages are still pretty narrow, I want you to match the width of the RAG page for all other pages to keep things consistent."
**Story:** n/a (owner request — supersedes the PLAN §7.1 "centered 46rem chat column (2× = 92rem at ≥1500px)" rule and the phase-58/27/91 form-column caps; the width lineage: `58_wide_desktop_column`, `86_history_page_width`).
**Context:** `frontend/assets/styles.css`: `.container` is the shared 72rem centered column (`width: 100%; max-width: 72rem; padding-inline: 1.25rem;`). The RAG view's `.sources-shell` (and `.git-sources-shell` / `.history-shell` / `.tokens-shell`) carry NO max-width — their content is the full 72rem container: **that is the width the owner wants everywhere**. The narrow pages: `:root { --chat-column: 46rem; }` caps `.chat-shell` (the chat view — the div IS `.container.chat-shell`, the later rule overriding the 72rem cap), `.shared-shell` (shared.html), `.doc-md` (the document viewer's reading column) and `.doc-summary:has(+ .doc-md)` (exactly four selectors use the token); `@media (min-width: 1500px) { :root { --chat-column: 92rem; } .doc-shell { max-width: calc(var(--chat-column) + 2 * 1.25rem); } }` (phase 58 — the wide-desktop doubling + the standalone document page's cap lift); and three hard-coded `max-width: 46rem` form columns: `.tuning-shell`, `.theme-shell` (phase 91), `.doc-edit-shell` (phase 59). Width pins live in: `tests/unit/test_wide_column_css.py` (the phase-58 contract file — 46rem base, the 92rem media block, the four-token count, the three-hard-coded-46rem negative pin, the provenance comments), `tests/unit/test_markdown_tables.py`, `test_shared_page.py`, `test_pinned_composer.py`, `test_doc_edit_screen.py`, `test_remove_confirm_modal.py`, `test_source_ignore_paths.py` (grep `46rem|92rem|chat-column` under `tests/` for the authoritative list — some hits are fixture text, judge per pin), and E2E measured-width suites: `tests/e2e/test_wide_desktop_column.py` (the measured 1472px/736px contract), `test_document_viewer.py`, `test_save_share_ux.py`, `test_sticky_navbar.py`, `test_markdown_tables.py`, `test_responsive_polish.py` (mobile no-overflow).

## Objective
Every view and page renders its content at the RAG page's width — the full 72rem container at every viewport (centered, with the container's 1.25rem gutters): the chat column, the Tuning and Theme form columns, the doc-edit screen, the shared page, and the document viewer all widen to 72rem; the phase-58 ≥1500px 92rem doubling and the 46rem form caps are retired; the mobile (≤640px) and tablet layouts are unchanged (everything was already full-width below the caps).

## Dependencies
- `86_history_page_width` / `58_wide_desktop_column` (complete) — the width lineage being revised (their suites are updated IN THIS PHASE, the phase-97 task-07/08 precedent — asserted behavior preserved, only the width contract changes).
- No code dependencies beyond `frontend/assets/styles.css` (CSS-only — `app/`, `frontend/*.html`, and every JS module are untouched).

## Decisions recorded here (owner instruction 2026-09-12 — PLAN.md is being redone by the owner)
- **D1 — one width for everything:** the reading/form columns ALL ride the 72rem container. `:root { --chat-column: 72rem; }` (the token stays — the four reading-column selectors keep `max-width: var(--chat-column)`, so `.doc-md`/`.shared-shell`/`.chat-shell`/the doc-summary panel follow automatically); the `@media (min-width: 1500px)` block is DELETED entirely (the 92rem doubling AND the `.doc-shell` cap lift — with the token at 72rem the standalone document page's `.container.doc-shell` simply keeps the 72rem cap); the three hard-coded `max-width: 46rem` caps (`.tuning-shell`, `.theme-shell`, `.doc-edit-shell`) are REMOVED (plus their `margin-inline: auto` centering — the `.container` ancestor centers; the shells keep their flex-column + gap rules, matching `.sources-shell` exactly). Net effect: ZERO literal `max-width: 46rem` rules remain in the file (the negative pin flips). This SUPERSEDES PLAN §7.1's 46rem/92rem rule and the phase-58 owner instruction of 2026-08-31 (recorded here per the phase-94/96/97 convention — the owner's new instruction wins; the PLAN.md anchor table gets the owner's sign-off separately).
- **D2 — the document viewer's modal is untouched:** the same-page doc modal's 1100px panel stays its effective ceiling (`.doc-md` at 72rem is wider than the panel's inner width, so the panel binds — no panel resize, no modal change). The standalone `document.html` page rides the 72rem container like every other page.
- **D3 — CSS-only, contracts intact:** no HTML change (the B4 byte-identical theme contract is unaffected — the served HTML is unchanged; only `styles.css` bytes change), no JS change, no endpoint change; A19's `?v=<deploy-token>` versioning busts the old CSS automatically. The `≤640px` mobile block is UNCHANGED (at 360px the container is already 100% — the caps never bound there; the mobile squeeze rules for chat/shared/tokens/theme keep working).
- **D4 — the comment sweep:** every stale "46rem base, 92rem at >=1500px" / "46rem column contract" / phase-58-provenance comment in `styles.css` is updated to the new contract (the owner instruction 2026-09-12 as provenance at the token + the note that the wide-desktop doubling was retired) — the house rule that comments carry the contract (and `test_wide_column_css.py` pins the comment states).

## Tasks
1. `01_width_css.md` — the CSS change: the token to 72rem, the media block deleted, the three form caps removed, the comment sweep
2. `02_width_unit_pins.md` — the unit pin updates: `test_wide_column_css.py` rewritten to the new contract + the grep-sweep of the other unit files
3. `03_e2e_width_sweep.md` — `test_wide_desktop_column.py` rewritten to the measured 72rem contract + the other E2E width pins + the regression sweep + the atomic commit

## Testing & Quality
- Unit: `tests/unit/test_wide_column_css.py` REWRITTEN to the new contract (the pins below); every other unit file whose pins reference the old widths updated (the grep sweep — `46rem|92rem|chat-column` under `tests/unit/`, judged per pin: a width assertion updates, fixture text does not).
- E2E (mandatory, A16): `uv run pytest tests/e2e/test_wide_desktop_column.py -v --no-cov` in isolation — the phase's dedicated width suite, REWRITTEN to the measured 72rem contract (the phase-97 task-07/08 precedent for updating a completed phase's suite when its contract changes); the other measured-width suites updated in place.
- Coverage: **>90%** on `app/` (untouched — the full-suite gate still runs).
- Lint/types: `uv run ruff check . && uv run pyright`.

## Completion Criteria
- [ ] at any viewport ≥ ~1200px, the chat, shared, document-viewer, Tuning, Theme, and doc-edit content columns measure the 72rem container width (E2E-measured, ±4 px) — identical to the RAG page's; below that, everything is full-width as today; 360px has no horizontal overflow
- [ ] `styles.css` has ZERO literal `max-width: 46rem` rules and NO `@media (min-width: 1500px)` block; the four reading-column selectors still cap with `var(--chat-column)` (now 72rem)
- [ ] the B4 byte-identical theme contract holds (no HTML change — the theme no-op test suite green); the mobile squeeze layouts green
- [ ] `uv run pytest` green; coverage >90%; ruff + pyright clean
- [ ] one atomic Conventional Commit, `--no-gpg-sign` (e.g. `feat(ui): match every page to the RAG page's 72rem width`)