## ADDED Requirements

### Requirement: Site themes
The site MUST support three themes:
- `dark`
- `light`
- `high-contrast`

Themes MUST be applied by setting a `data-theme` attribute on the root document element (`<html>`).

#### Scenario: Dark theme active
- **WHEN** `data-theme="dark"` is set on `<html>`
- **THEN** the site's background, text, and component styling reflect the dark palette

#### Scenario: Light theme active
- **WHEN** `data-theme="light"` is set on `<html>`
- **THEN** the site's background, text, and component styling reflect the light palette

#### Scenario: High contrast theme active
- **WHEN** `data-theme="high-contrast"` is set on `<html>`
- **THEN** the site uses a high-contrast palette with a clearly visible focus ring and high-contrast borders

### Requirement: Theme persistence
The site MUST persist the user's theme selection so it is retained across page loads and navigations.

Persistence MUST be stored locally in the browser (e.g., localStorage).

#### Scenario: Theme persists across reload
- **WHEN** the user selects `light` theme and reloads the page
- **THEN** the `light` theme remains active

### Requirement: Default theme selection
If the user has not explicitly selected a theme, the site MUST choose a default theme using environment signals.

Default selection order:
1) If forced colors / high-contrast mode is active, default to `high-contrast`
2) Else if the system prefers light color scheme, default to `light`
3) Else default to `dark`

#### Scenario: No stored preference uses system settings
- **WHEN** the user has no stored theme preference
- **THEN** the site selects a default theme based on forced-colors and prefers-color-scheme

### Requirement: Theme switching transition
Theme changes initiated by the user MUST transition smoothly.

The transition MUST be disabled or substantially reduced when `prefers-reduced-motion: reduce` is set.

#### Scenario: Smooth transition on switch
- **WHEN** the user switches from `dark` to `light` theme
- **THEN** theme-affecting properties transition smoothly instead of abruptly switching

#### Scenario: Reduced motion disables theme animation
- **WHEN** `prefers-reduced-motion: reduce` is set and the user switches theme
- **THEN** the theme change occurs without noticeable animation
