Now I remember the theme

openspec/changes/archive/2026-02-11-remember-theme/specs/analytics-umami/spec.md

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+## ADDED Requirements
+
+### Requirement: Theme switch tracking event
+When Umami is enabled, the site MUST emit a custom event when the user changes theme via the theme switcher UI.
+
+The site MUST emit the event using Umami's JavaScript API (`umami.track(...)`) so runtime properties can be included.
+
+The event name MUST be `theme_switch`.
+
+The emitted event MUST include, at minimum:
+- `target_id`
+- `placement`
+- `theme`
+
+#### Scenario: Theme switch emits event
+- **WHEN** a user selects `high-contrast` in the theme switcher notch
+- **THEN** the site emits a `theme_switch` event with `theme=high-contrast` and a stable `target_id`
+
+#### Scenario: Missing Umami does not break switching
+- **WHEN** Umami is not configured or the Umami script is not present
+- **THEN** theme switching and persistence still work and no browser error is thrown

openspec/changes/archive/2026-02-11-remember-theme/specs/interaction-tracking-taxonomy/spec.md

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+## ADDED Requirements
+
+### Requirement: Theme switch event taxonomy
+The tracking taxonomy MUST define an event for theme switching.
+
+The event name MUST be `theme_switch`.
+
+The `theme_switch` event MUST include, at minimum:
+- `target_id`
+- `placement`
+- `theme`
+
+The event SHOULD include `prev_theme` when available.
+
+The taxonomy MUST define the `target_id` namespace for theme switching as:
+- `theme.switch.<theme>`
+
+The taxonomy MUST define the `placement` value for the theme switcher notch as:
+- `theme_notch`
+
+#### Scenario: Theme switch target_id is deterministic
+- **WHEN** a user selects `light` theme using the theme notch
+- **THEN** the event is emitted with `target_id=theme.switch.light` and `placement=theme_notch`

openspec/changes/archive/2026-02-11-remember-theme/specs/site-theming/spec.md

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+## ADDED Requirements
+
+### Requirement: Theme persistence works across visits with fallback
+The site MUST persist the user's theme selection across visits so returning users see the last-selected theme.
+
+The site MUST use client-side persistence and MUST support a fallback mechanism:
+- Primary: `localStorage`
+- Fallback: a client-side cookie
+
+The effective theme selection order MUST be:
+1) Stored theme in `localStorage` (if available)
+2) Stored theme in a cookie (if localStorage is unavailable)
+3) Default selection using environment signals
+
+#### Scenario: LocalStorage persists across a later visit
+- **WHEN** a user selects `light` theme and later returns to the site in the same browser
+- **THEN** the site initializes in `light` theme before first paint
+
+#### Scenario: Cookie fallback is used when localStorage is unavailable
+- **WHEN** the browser environment blocks `localStorage` access and the user selects `dark` theme
+- **THEN** the theme is persisted using a client-side cookie and is restored on the next visit
+
+#### Scenario: No persistence available falls back to defaults
+- **WHEN** both `localStorage` and cookie persistence are unavailable
+- **THEN** the site falls back to default theme selection using environment signals