fix(web): distinguish thread search matches from code tints

[Yash-Singh1]

Problem

Thread search matches use theme colors that can blend into inline code, code blocks, or message bubbles. The default highlight colors also lack a clear light and dark mode distinction.

Change

Use amber search match colors across built-in themes, with a stronger gold for the active match. Set readable light and dark defaults for the browser highlight when a theme does not provide colors. Add palette checks for contrast and separation from nearby surfaces.

Scope and approval

This is a focused visual fix to the existing thread search feature. It changes only search match colors and their palette checks.

Verification

Added palette tests that check active match contrast and color distance from inline-code, code-block, and message surfaces. Tests were not run.

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — The PR changes the default search-highlight colors for the standard palette and all built-in themes, affecting the shipped appearance of existing thread search results in light and dark modes. The implementation is focused and includes palette checks, but the product-default changes warrant human review.

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[Yash-Singh1]

Search highlight comparisons

Before is on the left, after is on the right. Each image includes light mode above dark mode. Inactive matches use amber; the current match uses stronger gold. Inline code keeps its existing styling.

These are rendered samples using T3 Code's actual stylesheet, theme palettes, and search-highlight code. Full client verification hit a dev pairing HTTP 500.

T3 Chat

T3 Code

Grove

Ocean

Ember

Iris

Validation passed: 101 focused tests, targeted lint and formatting, and web typecheck. Palette checks require at least 4.5:1 text contrast and separation from code and message backgrounds.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

• Configuration used: Path: .coderabbit.config.ts
• Review profile: CHILL
• Plan: Team
• Run ID: 69d33beb-cb4a-462a-8a26-63b0c9322947

📥 Commits

Reviewing files that changed from the base of the PR and between 61b9790 and 1c17d58.

📒 Files selected for processing (3)

• apps/web/src/index.css
• apps/web/src/themePalette.test.ts
• packages/shared/src/themePalettes.ts

Included review availability: This review used your included allowance. Your plan provides up to 10 included reviews per hour; 9 remain after this review.

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📝 Walkthrough

Walkthrough

Search-match colors now use shared amber values across built-in themes. Thread-find highlights have light- and dark-mode fallback colors, and palette tests check color contrast and separation from other backgrounds.

Changes

Search highlights

Layer / File(s)	Summary
Search-match colors and validation packages/shared/src/themePalettes.ts, apps/web/src/index.css, apps/web/src/themePalette.test.ts	Built-in theme palettes use shared amber search-match colors. Thread-find highlights use explicit light- and dark-mode fallback colors, while theme variables retain precedence. Palette tests check Oklab color distances and retain minimum contrast checks.

Priority: ➖ Normal

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix

Suggested reviewers: juliusmarminge

Merge Risk: ⚪ Minimal · up to 1c17d

No concrete issue is established in the reviewed changes. The palette tests were not reported as run, so their results remain unverified.

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main change: distinguishing thread search matches from code tints.
Description check	✅ Passed	The description includes all required sections and clearly explains the problem, change, scope, and verification. It states that tests were not run, but it does not provide UI screenshots or test resu…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	5.0 KiB	4.9 KiB	−23 B (−0.5%)	6.8 KiB	✅
Codex	Thread snapshot wire	3.8 KiB	3.8 KiB	0 B (0.0%)	4.9 KiB	✅
Codex	Live turn WebSocket wire	1.2 KiB	1.2 KiB	−23 B (−1.9%)	2.0 KiB	✅
Codex	Live turn WebSocket decoded	20.9 KiB	20.8 KiB	−41 B (−0.2%)	29.3 KiB	✅
Codex	Live turn messages	2	1	−1 (−50.0%)	8	✅
Claude	Total thread wire	5.0 KiB	5.0 KiB	0 B (0.0%)	6.8 KiB	✅
Claude	Thread snapshot wire	3.8 KiB	3.8 KiB	0 B (0.0%)	4.9 KiB	✅
Claude	Live turn WebSocket wire	1.2 KiB	1.2 KiB	0 B (0.0%)	2.0 KiB	✅
Claude	Live turn WebSocket decoded	21.2 KiB	21.2 KiB	0 B (0.0%)	29.3 KiB	✅
Claude	Live turn messages	2	2	0 (0.0%)	8	✅

Baseline: 61b9790 · PR result: 1c17d58 · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 108.5 KiB
• Claude decoded thread snapshot: 108.8 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.