8f84cc6389deb520d634e6a597ba565d967f4cb4
1 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
 julien
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0ae7e0e23d |
feat(portal-shell): light / dark / auto theme switcher (#86)
## Summary
- Add a header dropdown letting users pick **light**, **dark**, or **auto** (follow the OS) color schemes. Choice persists in `localStorage`, applies on next reload, and reacts live to OS theme changes when in `auto`.
- Built on `@angular/cdk/menu` for accessible roving focus, escape-to-close, and proper `menuitemradio` semantics on the three options.
- Apply `dark:` variants across the shell (header, sidebar, main bg) and the existing two pages. No semantic-token refactor yet — that belongs in a future ADR (`--color-surface-1`, `--color-text-1`, …).
## Architecture
- [`LayoutStateService`](apps/portal-shell/src/app/state/layout-state.service.ts) grows a `themeMode: signal<'light'|'dark'|'auto'>` alongside the existing `sidebarCollapsed`, plus an `effectiveTheme` computed that resolves `auto` against the system preference. A side-effect toggles the `.dark` class on `<html>`, so every `dark:` Tailwind utility flips at once.
- Tailwind v4 dark mode is rewired to **class-based** via `@custom-variant dark (&:where(.dark, .dark *));` in `styles.css`. This overrides the v4 default (`prefers-color-scheme` only) so the user's explicit override wins over the OS preference.
- The switcher trigger reflects the **selected** mode (sun / moon / monitor), not the effective theme — so users can tell which mode they're in even when `auto` happens to resolve to the same scheme as a manual pick.
## Side-edits in the same PR (already validated in the chat)
- **Logo asset.** Replace `apf-small.svg` (94 kB — a base64-PNG wrapped in SVG markup, not actually vector) with `apf-small.png` (144×144, 7.6 kB after `sharp --kernel lanczos3 --compressionLevel 9`). Header swaps to the PNG. The wide vector `apf-portal.svg` stays around for future surfaces that want the horizontal lockup.
- **Revert FR strings** that crept into the header template — project rule (CLAUDE.md) is English-only for source artefacts; FR localisation will happen properly via `@angular/localize` (separate ADR).
## Decisions worth flagging
- **Dropdown over segmented control.** The CDK Menu pays its weight: accessible by default (proper `aria-haspopup`, focus management, ESC handling, click-outside dismissal), reusable for future header menus (user, language, notifications), and one tidy primitive rather than three competing buttons.
- **`auto` is the default,** not `light`. Most users have an OS-level preference already; respecting it is the least surprising baseline.
- **`<html>.dark` class lives at the root,** not on `<app-root>`. That's the Tailwind convention and it means CDK overlay popups (the menu itself, future dialogs) inherit the right theme without extra wiring.
- **Bundle delta +21 kB gzip** (100 → 121 kB initial). All of it is `@angular/cdk/{menu,overlay,a11y}` and the dark CSS rules. We stay well under the 300 kB budget. The CDK is already on the architecture menu (ADR-0016 — *UI stack: Angular CDK + TailwindCSS*) so this is on-strategy spend.
- **No semantic tokens yet.** The dark variants use raw Tailwind gray ramps (`dark:bg-gray-900`, etc.) instead of a `--color-surface-1` / `--color-text-1` token layer. That keeps the change tractable for now; promotion to semantic tokens deserves its own ADR with the design team in the loop.
## Accessibility (ADR-0016)
- Menu trigger has `aria-haspopup="menu"`, `aria-label` announcing the current mode + "(open menu)".
- Menu uses `role="menu"`, items use `role="menuitemradio"` with `aria-checked` — assistive tech announces the selection state correctly.
- All interactive controls keep the 44×44 px touch target.
- `prefers-reduced-motion: reduce` already covered by the sidebar transitions; theme switcher has no animations of its own.
- Contrast: dark surfaces are gray-900 + gray-800 border / gray-100 text — passes WCAG AA. Brand primary shifted to the `300` step in dark mode so the active states keep contrast against gray-900.
## What this PR explicitly does NOT do
- Tokenise the palette into semantic surface / text / border roles (next iteration, ADR-led).
- Localise UI strings (separate `@angular/localize` ADR + PR).
- Animate the theme transition (FOIT-style flicker on toggle is acceptable in v1; we can soften later with a `color-scheme` CSS transition if it bothers users).
## Test plan
- [x] `pnpm exec nx run-many -t lint test build --projects=portal-shell` — green (**33 / 33 specs**, +8 for the theme work).
- [x] Production build: **121 kB gzip initial** (was 100 kB). Under the 300 kB budget.
- [ ] Manual: toggle each of the three modes → header / sidebar / main / cards switch surface colors instantly; trigger glyph updates.
- [ ] Manual: pick `auto`, change OS theme → UI follows live (Chrome DevTools → Rendering → "Emulate CSS media feature prefers-color-scheme").
- [ ] Manual: reload after each pick → the chosen mode is restored.
- [ ] Manual: keyboard the trigger → ENTER opens menu, arrow keys navigate, ENTER selects, ESC closes; focus returns to the trigger on close.
- [ ] Manual: Lighthouse accessibility on `/` in dark mode — score unchanged from light mode.
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Co-authored-by: Julien Gautier <julien.gautier@apf.asso.fr>
Reviewed-on: #86
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