feat(portal-shell): light / dark / auto theme switcher (#86)
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## 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.

---------

Co-authored-by: Julien Gautier <julien.gautier@apf.asso.fr>
Reviewed-on: #86
This commit was merged in pull request #86.
This commit is contained in:
2026-05-11 03:01:11 +02:00
parent b6aa17f6a0
commit 0ae7e0e23d
20 changed files with 505 additions and 76 deletions
@@ -1,12 +1,14 @@
<header class="flex h-16 items-center border-b border-gray-200 bg-white">
<header
class="flex h-16 items-center border-b border-gray-200 bg-white dark:border-gray-800 dark:bg-gray-900"
>
<div class="header__logo-zone" [class.header__logo-zone--collapsed]="collapsed()">
<a
routerLink="/"
class="flex h-full items-center gap-3 rounded-md text-brand-primary-500 transition-colors hover:text-brand-primary-600 focus-visible:outline-2 focus-visible:outline-offset-4 focus-visible:outline-brand-primary-500"
class="flex h-full items-center gap-3 rounded-md text-brand-primary-500 transition-colors hover:text-brand-primary-600 focus-visible:outline-2 focus-visible:outline-offset-4 focus-visible:outline-brand-primary-500 dark:text-brand-primary-300 dark:hover:text-brand-primary-200"
[class.justify-center]="collapsed()"
>
<img
src="logos/apf-portal.svg"
src="logos/apf-small.png"
alt=""
aria-hidden="true"
width="36"
@@ -23,14 +25,14 @@
<form role="search" class="mx-2 hidden flex-1 md:flex" (submit)="$event.preventDefault()">
<label class="sr-only" for="global-search">Search the portal</label>
<div
class="flex w-full max-w-xl items-center gap-2 rounded-full border border-gray-200 bg-gray-50 px-4 py-2 focus-within:border-brand-primary-500 focus-within:bg-white focus-within:ring-2 focus-within:ring-brand-primary-200"
class="flex w-full max-w-xl items-center gap-2 rounded-full border border-gray-200 bg-gray-50 px-4 py-2 focus-within:border-brand-primary-500 focus-within:bg-white focus-within:ring-2 focus-within:ring-brand-primary-200 dark:border-gray-700 dark:bg-gray-800 dark:focus-within:border-brand-primary-300 dark:focus-within:bg-gray-900 dark:focus-within:ring-brand-primary-700"
>
<app-icon name="search" [size]="18" />
<input
id="global-search"
type="search"
placeholder="Search…"
class="w-full bg-transparent text-sm text-gray-800 placeholder:text-gray-400 focus:outline-none"
class="w-full bg-transparent text-sm text-gray-800 placeholder:text-gray-400 focus:outline-none dark:text-gray-100 dark:placeholder:text-gray-500"
/>
</div>
</form>
@@ -38,25 +40,26 @@
<nav aria-label="Primary" class="ml-auto flex items-center gap-1">
<button
type="button"
class="relative inline-flex h-11 w-11 items-center justify-center rounded-full text-gray-600 transition-colors hover:bg-gray-100 hover:text-brand-primary-500 focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-brand-primary-500"
class="relative inline-flex h-11 w-11 items-center justify-center rounded-full text-gray-600 transition-colors hover:bg-gray-100 hover:text-brand-primary-500 focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-brand-primary-500 dark:text-gray-300 dark:hover:bg-gray-800 dark:hover:text-brand-primary-300"
aria-label="Notifications"
>
<app-icon name="bell" />
<span
aria-hidden="true"
class="absolute right-2 top-2 h-2 w-2 rounded-full bg-brand-accent-400 ring-2 ring-white"
class="absolute right-2 top-2 h-2 w-2 rounded-full bg-brand-accent-400 ring-2 ring-white dark:ring-gray-900"
></span>
</button>
<button
type="button"
class="inline-flex h-11 w-11 items-center justify-center rounded-full text-gray-600 transition-colors hover:bg-gray-100 hover:text-brand-primary-500 focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-brand-primary-500"
class="inline-flex h-11 w-11 items-center justify-center rounded-full text-gray-600 transition-colors hover:bg-gray-100 hover:text-brand-primary-500 focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-brand-primary-500 dark:text-gray-300 dark:hover:bg-gray-800 dark:hover:text-brand-primary-300"
aria-label="Help"
>
<app-icon name="circle-help" />
</button>
<app-theme-switcher />
<button
type="button"
class="inline-flex h-11 w-11 items-center justify-center rounded-full text-gray-600 transition-colors hover:bg-gray-100 hover:text-brand-primary-500 focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-brand-primary-500"
class="inline-flex h-11 w-11 items-center justify-center rounded-full text-gray-600 transition-colors hover:bg-gray-100 hover:text-brand-primary-500 focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-brand-primary-500 dark:text-gray-300 dark:hover:bg-gray-800 dark:hover:text-brand-primary-300"
aria-label="Settings"
>
<app-icon name="settings" />
@@ -15,6 +15,10 @@
border-right: 1px solid #e5e7eb;
transition: width 0.18s ease-out;
:where(.dark) & {
border-right-color: #1f2937;
}
&--collapsed {
width: 4rem;
padding: 0 0.5rem;
@@ -48,6 +48,12 @@ describe('Header', () => {
expect(root.querySelector('button[aria-label="Settings"]')).not.toBeNull();
});
it('embeds the theme switcher', async () => {
const fixture = TestBed.createComponent(Header);
await fixture.whenStable();
expect(fixture.nativeElement.querySelector('app-theme-switcher')).not.toBeNull();
});
it('renders the logo zone, expanded with wordmark by default', async () => {
const fixture = TestBed.createComponent(Header);
fixture.detectChanges();
@@ -1,6 +1,7 @@
import { ChangeDetectionStrategy, Component, inject } from '@angular/core';
import { RouterLink } from '@angular/router';
import { Icon } from '../icon/icon';
import { ThemeSwitcher } from '../theme-switcher/theme-switcher';
import { LayoutStateService } from '../../state/layout-state.service';
/**
@@ -23,7 +24,7 @@ import { LayoutStateService } from '../../state/layout-state.service';
*/
@Component({
selector: 'app-header',
imports: [RouterLink, Icon],
imports: [RouterLink, Icon, ThemeSwitcher],
templateUrl: './header.html',
styleUrl: './header.scss',
changeDetection: ChangeDetectionStrategy.OnPush,