phase: 116_modal_scrollbar_theme

All verification complete — every gate re-run independently and green. Final report:

**Phase 116 final verification pass — all green (work was already in the tree; verified, nothing to fix)**

- **Verified** `styles.css`: `--scrollbar-thumb`/`--scrollbar-track` tokens in `:root` (color-mix derivations — follow the saved theme, not in BUILTIN_COLORS; contrast 3.73:1 ≥ 3:1, recomputed independently) + scoped rules `.doc-modal .doc-raw` (overflow-x already owned by the element)
- **Verified** E2E test 8 `test_raw_code_block_themed_scrollbar`: overflow, scroll action, computed-style theme assertions, screenshot
- **Screenshots visually confirmed**: headed `doc_modal_scrollbar_themed_1280.png` shows muted rounded thumb on dark track, no native light-gray bar; headless suite shot records scrolled state (headless Chromium paints no bar UI — documented in test docstring)

**Test / lint / coverage (re-run by me):**
- `uv run pytest tests/e2e/test_document_viewer.py -v --no-cov` → **8 passed** (isolation)
- `uv run pytest --cov=app --cov-report=term` → **2457 passed, app/ 99%** (>90% ✓)
- `uv run pytest tests/e2e/test_dark_tech_theme.py -v --no-cov` → **6 passed** (no token collision)
- `uv run ruff check .` → clean; `uv run pyright` → 0 errors, 0 warnings

**Completion criteria:**
1. Modal scrolls horizontally, scrollbar themed, screenshot shows no native bar — ✅
2. No global scrollbar change (all new selectors under `.doc-modal`; grep-confirmed), regressions green — ✅
3. pytest green, coverage >90%, e2e isolated green, ruff+pyright clean — ✅
4. `--no-gpg-sign` commit + phase move — harness job (left uncommitted in working tree, per rules)

**No defects found; no deviations. Next pending phase:** none — `todo/` contains only phase 116.

.agents/phases/complete/116_modal_scrollbar_theme/00_phase.md

@@ -0,0 +1,39 @@
+# Phase 116 — Document modal: themed code-block scrollbar (TODO L3)
+
+**Source:** `TODO.md` L88–99 — "L3 — Document modal: native unstyled horizontal scrollbar in the code block (cosmetic) (2026-09-15, brain-of-reese interactive test)"
+**Story:** `document-viewer.md` — the modal belongs to the document-viewer story (the same-page chip viewer, phase 26).
+**Context:** The document modal (the almost-fullscreen chip viewer, `.doc-modal` — `frontend/assets/styles.css:4117+`) shows the raw content in a code block; long lines (e.g. a `quest::say(...)` line in a quest `.pl` file) overflow horizontally and reveal the **browser-native, unstyled scrollbar** (light-gray bar) — it clashes with the dark theme, and long lines clip at the right edge.
+
+## Objective
+The modal's code block scrolls horizontally with a themed scrollbar (`scrollbar-color` for Firefox, `::-webkit-scrollbar` pseudos for Chromium), consistent with the dark theme; long lines stay unwrapped (code stays code) and scroll instead of clipping.
+
+## Dependencies
+- `115_doc_draft_discard` (todo) — pipeline predecessor (execution order) only; no code dependency (CSS + one E2E file).
+
+## Design (shared by all tasks — the executor reads this, not the chat)
+- **Theme tokens (task 01):** two CSS custom properties in the theme's token block: `--scrollbar-thumb` (a muted theme color, ≥3:1 against the track — a scrollbar is a UI component, non-text contrast AA) and `--scrollbar-track` (near the code-block background). Scope: the modal's raw-content code element **only** (confirm the exact selector from `frontend/assets/document-modal.js` / the `.doc-modal` rules) — no global scrollbar restyle (out of scope; the TODO asks only about the modal).
+- **Rules (task 01):** on the modal code block: `overflow-x: auto` (confirm present — add if the element relies on an ancestor), `scrollbar-width: thin`, `scrollbar-color: var(--scrollbar-thumb) var(--scrollbar-track)` (Firefox), and the Chromium pair: `::-webkit-scrollbar { height: 8px }`, `::-webkit-scrollbar-track { background: var(--scrollbar-track) }`, `::-webkit-scrollbar-thumb { background: var(--scrollbar-thumb); border-radius: 4px }`.
+- **E2E (task 02):** the document-viewer story gains a check: open the modal on a document with a long line → the code block is horizontally scrollable (`scrollWidth > clientWidth`; a scroll action moves it) → a screenshot to `.agents/screenshots/` (house convention) as the visual record.
+
+## Tasks
+1. `01_themed_scrollbar.md` — the theme tokens + the scoped scrollbar rules.
+2. `02_scrollbar_e2e_check.md` — the E2E scroll check + screenshot.
+
+## Testing & Quality
+- E2E: `tests/e2e/test_document_viewer.py` (existing — extend, task 02); run in isolation: `uv run pytest tests/e2e/test_document_viewer.py -v --no-cov`.
+- CSS: no unit layer for CSS — the E2E check + screenshot are the gate; the dark-theme suite (`tests/e2e/test_dark_tech_theme.py`) must stay green (no token collision).
+- Coverage: n/a (no app/ code change) — the validate.sh gate stays green.
+
+## Completion Criteria
+- [ ] The modal's code block scrolls horizontally; the scrollbar is themed — the screenshot in `.agents/screenshots/` shows no native light-gray bar.
+- [ ] No global scrollbar change (the new selector is scoped under `.doc-modal` — grep); the other pages are visually unchanged (regression suites green).
+- [ ] `uv run pytest` green; coverage >90%; the e2e file green in isolation; `uv run ruff check . && uv run pyright` clean.
+- [ ] One `--no-gpg-sign` commit; phase dir moved to `complete/` by the pipeline gate.
+
+## Locked decisions
+- **A1 — keep horizontal scroll (NO line-wrap) for the code content (owner-confirmed 2026-09-14, roadmap confirmation — the TODO's "consider wrapping long lines per content type" is rejected for code: wrapping breaks code readability; the themed scrollbar is the fix).**
+
+## Commit
+```bash
+git add frontend/ tests/ .agents/phases/ && git commit --no-gpg-sign -m "style(ui): theme the document modal's code-block horizontal scrollbar (scrollbar-color + webkit pseudos)"
+```