diff --git a/docs/superpowers/plans/2026-06-07-dark-mode-theme-toggle.md b/docs/superpowers/plans/2026-06-07-dark-mode-theme-toggle.md new file mode 100644 index 0000000..d694447 --- /dev/null +++ b/docs/superpowers/plans/2026-06-07-dark-mode-theme-toggle.md @@ -0,0 +1,520 @@ +# Dark-Mode Theme Toggle Implementation Plan + +> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking. + +**Goal:** Ship a tri-state (Light/Dark/System) theme toggle that activates the existing `.dark` token set, persists to `localStorage`, defaults to System (live-tracking the OS), and never flashes on reload. + +**Architecture:** Client-only theming over CSS custom properties — no new dependency. A framework-free core (`theme.ts`) resolves/reads/applies the theme; a `useTheme` hook mirrors `use-locale`; a synchronous inline script in `index.html` applies the class before first paint; an icon segmented `ThemeSwitch` lives in the header next to `LangSwitch`. The `.dark` class on `` activates the dark tokens migrated in #49. + +**Tech Stack:** React 19 + TS + pnpm, Tailwind v4 (OKLCH tokens in `index.css`), lucide-react (already a dep), Vitest + RTL + MSW + Storybook. Test runner: `pnpm test` (vitest, single pass). + +**Conventions:** pnpm; **no `any`/`eslint-disable`/`@ts-ignore`**; no codename; en/sv parity; source double-quote/semicolon, stories single-quote/no-semicolon; token classes only (no raw colors — `check:colors` must pass); guard DOM globals (`window`/`localStorage`/`matchMedia`/`document`) for jsdom/test safety. + +**Spec:** `docs/superpowers/specs/2026-06-07-dark-mode-theme-toggle-design.md` + +**File structure:** +- `web/src/theme/theme.ts` (new) — `THEME_KEY`, `Theme`, `resolveTheme`, `readTheme`, `applyTheme`. +- `web/src/theme/theme.test.ts` (new) — unit tests for the core. +- `web/src/theme/use-theme.ts` (new) — `useTheme()` hook. +- `web/src/shell/theme-switch.tsx` (new) — the icon segmented control. +- `web/src/shell/theme-switch.test.tsx` (new) — interaction tests. +- `web/src/shell/theme-switch.stories.tsx` (new) — Storybook story. +- `web/src/shell/app-shell.tsx` (modify) — mount ``. +- `web/src/i18n/en.json`, `web/src/i18n/sv.json` (modify) — `theme.*` keys. +- `web/index.html` (modify) — inline FOUC-prevention script. +- `web/src/index.css` (modify) — dark `--primary`/`--ring` contrast tweak. + +--- + +# Task 1: Theme core (`theme.ts`) + unit tests + +**Files:** +- Create: `web/src/theme/theme.ts` +- Create: `web/src/theme/theme.test.ts` + +- [ ] **Step 1: Write the failing tests** — `web/src/theme/theme.test.ts`: + +```ts +import { afterEach, expect, test, vi } from "vitest"; +import { applyTheme, readTheme, resolveTheme, THEME_KEY } from "./theme"; + +function mockMatchMedia(matches: boolean) { + vi.stubGlobal("matchMedia", (query: string) => ({ + matches, + media: query, + onchange: null, + addEventListener: vi.fn(), + removeEventListener: vi.fn(), + addListener: vi.fn(), + removeListener: vi.fn(), + dispatchEvent: vi.fn(), + })); +} + +afterEach(() => { + vi.unstubAllGlobals(); + localStorage.clear(); + document.documentElement.classList.remove("dark"); +}); + +test("resolveTheme returns explicit values verbatim", () => { + expect(resolveTheme("light")).toBe("light"); + expect(resolveTheme("dark")).toBe("dark"); +}); + +test("resolveTheme maps system via prefers-color-scheme", () => { + mockMatchMedia(true); + expect(resolveTheme("system")).toBe("dark"); + mockMatchMedia(false); + expect(resolveTheme("system")).toBe("light"); +}); + +test("readTheme defaults to system when unset or invalid", () => { + expect(readTheme()).toBe("system"); + localStorage.setItem(THEME_KEY, "bogus"); + expect(readTheme()).toBe("system"); + localStorage.setItem(THEME_KEY, "dark"); + expect(readTheme()).toBe("dark"); +}); + +test("applyTheme toggles the dark class on documentElement", () => { + mockMatchMedia(false); + applyTheme("dark"); + expect(document.documentElement.classList.contains("dark")).toBe(true); + applyTheme("light"); + expect(document.documentElement.classList.contains("dark")).toBe(false); + mockMatchMedia(true); + applyTheme("system"); + expect(document.documentElement.classList.contains("dark")).toBe(true); +}); +``` + +- [ ] **Step 2: Run to verify it fails** + +Run: `cd web && pnpm vitest run src/theme/theme.test.ts` +Expected: FAIL — cannot import from `./theme` (module not found). + +- [ ] **Step 3: Implement** — `web/src/theme/theme.ts`: + +```ts +export const THEME_KEY = "theme"; + +export type Theme = "light" | "dark" | "system"; + +const THEMES: readonly Theme[] = ["light", "dark", "system"]; + +function prefersDark(): boolean { + return ( + typeof window !== "undefined" && + typeof window.matchMedia === "function" && + window.matchMedia("(prefers-color-scheme: dark)").matches + ); +} + +export function resolveTheme(theme: Theme): "light" | "dark" { + if (theme === "light" || theme === "dark") return theme; + return prefersDark() ? "dark" : "light"; +} + +export function readTheme(): Theme { + if (typeof localStorage === "undefined") return "system"; + const stored = localStorage.getItem(THEME_KEY); + return THEMES.includes(stored as Theme) ? (stored as Theme) : "system"; +} + +export function applyTheme(theme: Theme): void { + if (typeof document === "undefined") return; + document.documentElement.classList.toggle("dark", resolveTheme(theme) === "dark"); +} +``` + +- [ ] **Step 4: Run to verify it passes** + +Run: `cd web && pnpm vitest run src/theme/theme.test.ts` +Expected: PASS (4 tests). + +- [ ] **Step 5: Commit** + +```bash +git add web/src/theme/theme.ts web/src/theme/theme.test.ts +git commit -m "feat(web): theme core — resolve/read/apply tri-state theme (#59)" +``` + +--- + +# Task 2: `useTheme` hook + +**Files:** +- Create: `web/src/theme/use-theme.ts` + +(No standalone unit test — the hook is exercised by `theme-switch.test.tsx` in Task 3, which drives it through real UI per the project's testing style. `theme.ts` carries the logic and is unit-tested in Task 1.) + +- [ ] **Step 1: Implement** — `web/src/theme/use-theme.ts`: + +```ts +import { useEffect, useState } from "react"; + +import { applyTheme, readTheme, type Theme } from "./theme"; + +export function useTheme(): { theme: Theme; setTheme: (theme: Theme) => void } { + const [theme, setThemeState] = useState(readTheme); + + const setTheme = (next: Theme) => { + if (typeof localStorage !== "undefined") localStorage.setItem("theme", next); + setThemeState(next); + applyTheme(next); + }; + + useEffect(() => { + applyTheme(theme); + if (theme !== "system") return; + if (typeof window === "undefined" || typeof window.matchMedia !== "function") return; + const mql = window.matchMedia("(prefers-color-scheme: dark)"); + const onChange = () => applyTheme("system"); + mql.addEventListener("change", onChange); + return () => mql.removeEventListener("change", onChange); + }, [theme]); + + return { theme, setTheme }; +} +``` + +Note: import `THEME_KEY` from `./theme` and use it instead of the literal `"theme"` for the +`localStorage.setItem` key (DRY with the core). Update the import line to +`import { applyTheme, readTheme, THEME_KEY, type Theme } from "./theme";` and use +`localStorage.setItem(THEME_KEY, next)`. + +- [ ] **Step 2: Typecheck** + +Run: `cd web && pnpm typecheck` +Expected: PASS (no errors). + +- [ ] **Step 3: Commit** + +```bash +git add web/src/theme/use-theme.ts +git commit -m "feat(web): useTheme hook with live system tracking (#59)" +``` + +--- + +# Task 3: `ThemeSwitch` UI + i18n + tests + story + +**Files:** +- Create: `web/src/shell/theme-switch.tsx` +- Create: `web/src/shell/theme-switch.test.tsx` +- Create: `web/src/shell/theme-switch.stories.tsx` +- Modify: `web/src/i18n/en.json`, `web/src/i18n/sv.json` + +- [ ] **Step 1: Add i18n keys.** In `web/src/i18n/en.json`, add a top-level `theme` namespace (place after the `labels` entry): + +```json + "theme": { "light": "Light", "dark": "Dark", "system": "System" }, +``` + +In `web/src/i18n/sv.json`, the matching entry: + +```json + "theme": { "light": "Ljust", "dark": "Mörkt", "system": "System" }, +``` + +- [ ] **Step 2: Write the failing test** — `web/src/shell/theme-switch.test.tsx`: + +```tsx +import { afterEach, beforeEach, expect, test, vi } from "vitest"; +import { screen } from "@testing-library/react"; +import userEvent from "@testing-library/user-event"; +import { renderApp } from "../test/render"; +import { ThemeSwitch } from "./theme-switch"; + +beforeEach(() => { + vi.stubGlobal("matchMedia", (query: string) => ({ + matches: false, + media: query, + onchange: null, + addEventListener: vi.fn(), + removeEventListener: vi.fn(), + addListener: vi.fn(), + removeListener: vi.fn(), + dispatchEvent: vi.fn(), + })); +}); + +afterEach(() => { + vi.unstubAllGlobals(); + localStorage.clear(); + document.documentElement.classList.remove("dark"); +}); + +test("selecting Dark applies the dark class and persists", async () => { + renderApp(); + await userEvent.click(screen.getByRole("button", { name: /dark/i })); + expect(document.documentElement.classList.contains("dark")).toBe(true); + expect(localStorage.getItem("theme")).toBe("dark"); + expect(screen.getByRole("button", { name: /dark/i })).toHaveAttribute( + "aria-pressed", + "true", + ); +}); + +test("selecting Light removes the dark class and persists", async () => { + localStorage.setItem("theme", "dark"); + renderApp(); + await userEvent.click(screen.getByRole("button", { name: /light/i })); + expect(document.documentElement.classList.contains("dark")).toBe(false); + expect(localStorage.getItem("theme")).toBe("light"); +}); + +test("selecting System resolves via prefers-color-scheme", async () => { + vi.stubGlobal("matchMedia", (query: string) => ({ + matches: true, + media: query, + onchange: null, + addEventListener: vi.fn(), + removeEventListener: vi.fn(), + addListener: vi.fn(), + removeListener: vi.fn(), + dispatchEvent: vi.fn(), + })); + renderApp(); + await userEvent.click(screen.getByRole("button", { name: /system/i })); + expect(localStorage.getItem("theme")).toBe("system"); + expect(document.documentElement.classList.contains("dark")).toBe(true); +}); +``` + +- [ ] **Step 3: Run to verify it fails** + +Run: `cd web && pnpm vitest run src/shell/theme-switch.test.tsx` +Expected: FAIL — cannot import `ThemeSwitch`. + +- [ ] **Step 4: Implement** — `web/src/shell/theme-switch.tsx`: + +```tsx +import { Monitor, Moon, Sun } from "lucide-react"; +import { useTranslation } from "react-i18next"; + +import { useTheme } from "../theme/use-theme"; +import type { Theme } from "../theme/theme"; +import { cn } from "@/lib/utils"; + +const OPTIONS: { value: Theme; Icon: typeof Sun }[] = [ + { value: "light", Icon: Sun }, + { value: "dark", Icon: Moon }, + { value: "system", Icon: Monitor }, +]; + +export function ThemeSwitch() { + const { t } = useTranslation(); + const { theme, setTheme } = useTheme(); + + return ( +
+ {OPTIONS.map(({ value, Icon }) => { + const active = theme === value; + return ( + + ); + })} +
+ ); +} +``` + +(Verify the `cn` import path matches the project — other `ui/*` files import `cn` from `@/lib/utils`. If `lib/utils` is absent, mirror whatever `button.tsx` uses.) + +- [ ] **Step 5: Run to verify it passes** + +Run: `cd web && pnpm vitest run src/shell/theme-switch.test.tsx` +Expected: PASS (3 tests). + +- [ ] **Step 6: Write the Storybook story** — `web/src/shell/theme-switch.stories.tsx`: + +```tsx +import type { Meta, StoryObj } from '@storybook/react-vite' +import { expect } from 'storybook/test' + +import { ThemeSwitch } from './theme-switch' + +const meta = { + component: ThemeSwitch, + tags: ['ai-generated'], +} satisfies Meta + +export default meta +type Story = StoryObj + +export const Default: Story = { + play: async ({ canvas }) => { + await expect(canvas.getByRole('button', { name: /light/i })).toBeInTheDocument() + await expect(canvas.getByRole('button', { name: /dark/i })).toBeInTheDocument() + await expect(canvas.getByRole('button', { name: /system/i })).toBeInTheDocument() + }, +} +``` + +(Note: the story exercises rendering only — it does not click options, to avoid mutating `` +globally across the browser-mode test run.) + +- [ ] **Step 7: Run the story as a test + lint** + +Run: `cd web && pnpm vitest run src/shell/theme-switch.stories.tsx && pnpm lint` +Expected: PASS. + +- [ ] **Step 8: Commit** + +```bash +git add web/src/shell/theme-switch.tsx web/src/shell/theme-switch.test.tsx web/src/shell/theme-switch.stories.tsx web/src/i18n/en.json web/src/i18n/sv.json +git commit -m "feat(web): ThemeSwitch icon segmented control + theme.* i18n (#59)" +``` + +--- + +# Task 4: Mount in the header + FOUC inline script + +**Files:** +- Modify: `web/src/shell/app-shell.tsx` +- Modify: `web/index.html` + +- [ ] **Step 1: Mount `ThemeSwitch`.** In `web/src/shell/app-shell.tsx`, add the import: + +```tsx +import { ThemeSwitch } from "./theme-switch"; +``` + +and render it in the header immediately before ``: + +```tsx +
+ + +``` + +(Match the existing header's exact JSX; only insert the one line. Do not change other markup.) + +- [ ] **Step 2: Add the FOUC-prevention inline script.** In `web/index.html`, inside `` + BEFORE the ` +``` + +- [ ] **Step 3: Verify the app-shell test still passes** (the header now has an extra control): + +Run: `cd web && pnpm vitest run src/shell/app-shell.test.tsx` +Expected: PASS (the existing "language switch" test is unaffected — ThemeSwitch buttons have distinct accessible names). + +- [ ] **Step 4: Build to verify `index.html` is valid** + +Run: `cd web && pnpm build` +Expected: built successfully (Vite processes the inline script). + +- [ ] **Step 5: Commit** + +```bash +git add web/src/shell/app-shell.tsx web/index.html +git commit -m "feat(web): mount ThemeSwitch in header + pre-paint theme init (#59)" +``` + +--- + +# Task 5: Dark `--primary` contrast tweak + final verification + +**Files:** +- Modify: `web/src/index.css` + +- [ ] **Step 1: Compute the new dark `--primary`.** The dark button label uses `--primary-foreground: + oklch(0.205 0 0)` (near-black) on `--primary: oklch(0.673 0.182 276.935)` (~3.21:1). Lower the + lightness (and keep it a recognizable indigo) until WCAG contrast vs `oklch(0.205 0 0)` is **≥4.5:1**. + A good starting point is `oklch(0.62 0.20 277)`; compute the exact value with a contrast check + (convert both to sRGB relative luminance, `(L1+0.05)/(L2+0.05) ≥ 4.5`). In the `.dark` block of + `web/src/index.css`, update BOTH `--primary` and `--ring` (they must match) to the chosen value: + +```css + --primary: oklch( 277); + ... + --ring: oklch( 277); +``` + +Leave `--primary-foreground: oklch(0.205 0 0)` and the entire `:root` (light) block unchanged. + +- [ ] **Step 2: Verify the contrast.** State the computed ratio in the commit body (must be ≥4.5:1). + Sanity-check the value is still visibly indigo (hue ~277, chroma not flattened to gray). + +- [ ] **Step 3: Full gate (single test pass).** + +Run: +```bash +cd web && pnpm typecheck && pnpm lint && pnpm test && pnpm build && pnpm check:size && pnpm check:colors +``` +Expected: all green. `check:colors` passes (icons are not color utilities). `check:size` within 250 KB +gz (three lucide icons are negligible). Tests run exactly ONCE (no concurrent runs). + +- [ ] **Step 4: Codename + status checks.** + +```bash +git grep -in 'biggus\|dickus' -- web/src web/index.html; echo "codename-exit=$?" +git status --short +``` +Expected: no codename matches; working tree shows only intended changes. + +- [ ] **Step 5: Manual smoke (recommended).** `pnpm dev`, toggle Light/Dark/System; confirm the app + switches, a dark reload doesn't flash light, primary buttons are legible in dark, and switching the + OS theme while in System updates the app live. + +- [ ] **Step 6: Commit** + +```bash +git add web/src/index.css +git commit -m "fix(web): raise dark --primary contrast to AA for button labels (#59)" +``` + +--- + +## Self-Review (completed) + +**Spec coverage:** tri-state model + System default (T1 `resolveTheme`/`readTheme`, T3 UI); persisted +to localStorage (T2 `setTheme`, T3 tests); `.dark` on `` (T1 `applyTheme`); live system tracking +(T2 `useEffect` matchMedia listener); FOUC prevention (T4 inline script); icon segmented control next +to LangSwitch (T3 + T4 mount); en/sv `theme.*` (T3); aria-pressed/aria-label (T3); dark `--primary` +contrast ≥4.5:1 + `--ring` sync (T5); gate incl. check:colors/check:size + no codename + no new dep +(T5). All acceptance criteria 1–6 mapped. ✓ + +**Placeholder scan:** the only "computed" value is the exact dark `--primary` OKLCH — a genuine WCAG +measurement step with a concrete starting point and an explicit acceptance threshold (≥4.5:1), not a +TODO. All code blocks are complete. ✓ + +**Type consistency:** `Theme` type defined in `theme.ts` (T1), imported by `use-theme.ts` (T2) and +`theme-switch.tsx` (T3); `THEME_KEY` from `theme.ts` used in T2's setter; `resolveTheme`/`readTheme`/ +`applyTheme` signatures consistent across tasks; i18n keys `theme.light/dark/system` defined in T3 and +referenced by `t(\`theme.${value}\`)` in T3's component. ✓ + +## Notes +- No new dependency (lucide-react already present; `.dark` tokens already exist from #49). +- The inline FOUC script is intentionally plain ES5-ish + try/catch — it runs before the bundle and + must never throw. +- Cross-tab sync and per-account/server theme default are explicit follow-ups (not in this plan).