fix(a11y): dark-adapt stroke semantic tokens (D12)

[BrianGenisio]

Summary

Closes #23 ([a11y][D12]). Dark-mode --Colors-Stroke-* tokens no longer copy the light near-white scale, so borders/dividers stop glowing on dark surfaces. Visual change for all DS consumers — please confirm with design-system owners before merge (same process as A7/A8).

Also dark-adapts --Colors-Buttons-Tertiary-Default (the tertiary border color), which stayed Neutral-300 in dark and was the ChatCPT local workaround.

Token changes (dark only; light unchanged)

Token	Before (same as light)	After
--Colors-Stroke-Background	Neutral-20	Neutral-1300
--Colors-Stroke-Lighter	Neutral-100	Neutral-1250
--Colors-Stroke-Light	Neutral-150	Neutral-1200
--Colors-Stroke-Default	Neutral-200	Neutral-1150
--Colors-Stroke-Medium	Neutral-300	Neutral-1100
--Colors-Stroke-Strong	Neutral-400	Neutral-1000
--Colors-Stroke-Stronger	Neutral-550	Neutral-900
--Colors-Stroke-Primary	Primary-600	Primary-450
--Colors-Stroke-Primary-Light	Primary-350	Primary-500
--Colors-Stroke-Primary-Medium	Primary-500	Primary-450
--Colors-Stroke-Primary-Dark	Primary-800	Primary-600
--Colors-Buttons-Tertiary-Default	Neutral-300 (unchanged in dark)	Neutral-1100

Values align with existing dark input/box borders and A7’s Primary-450 focus token. Lighter → Stronger rank is preserved (closer to Main-Top → more contrast).

Notes for consumers

• After submodule bump, ChatCPT can remove:
  • app.css tertiary border override (--Colors-Buttons-Tertiary-Default)
  • rest-pill darkening if it was only compensating for non-adaptive strokes
• Components that already hardcode dark borders (e.g. input’s Neutral-1250) are unchanged; semantic Stroke consumers (modal dividers, tables, horizontal-card dashed borders, etc.) will pick this up automatically.

Test plan

• npm test — 48/48, including new D12 regression in tests/contrast-tokens.spec.js (dark strokes ≠ light near-white; Strong > Default luminance; tertiary border adapts)
• Design-system owner visual review in dark mode (colors/test.html, modal, table, input, tertiary button)
• After submodule bump: remove ChatCPT local stroke/tertiary workarounds and spot-check borders

Made with Cursor

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 01846686-4bf1-4733-b9c1-9c034aedfc36

📥 Commits

Reviewing files that changed from the base of the PR and between c8bc490 and 2771d64.

📒 Files selected for processing (4)

• colors/README.md
• colors/colors.css
• components/button/button.css
• tests/contrast-tokens.spec.js

---

📝 Walkthrough

Walkthrough

Dark-mode stroke tokens now map to darker neutral and primary values. The tertiary button border uses a dark neutral token in dark mode. Contrast tests now calculate luminance and verify stroke adaptation, luminance ordering, and tertiary-border behavior. Documentation describes the remapping, semantic stroke-token usage, and expanded contrast coverage.

Mergeability Score: ⚪ Minimal · up to 2771d

This change updates dark-mode stroke and tertiary button tokens with regression coverage; no actionable merge-blocking risk remains beyond normal checks and design review.

🚥 Pre-merge checks | ✅ 3 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Linked Issues check	⚠️ Warning	The PR implements the required token changes and documents consumer impact, but design-system owner sign-off remains pending.	Obtain design-system owner visual sign-off and update the linked issue or PR before merge.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the dark-mode stroke-token accessibility fix and references D12.
Description check	✅ Passed	The description explains the dark-mode stroke changes, tertiary border update, consumer impact, and test status.
Out of Scope Changes check	✅ Passed	All changed files support stroke adaptation, tertiary-border adaptation, documentation, or regression testing; no unrelated changes are shown.

---

_{Comment @coderabbitai help to get the list of available commands.}

[BrianGenisio]

I don't like this.