Now I remember the theme

openspec/specs/analytics-umami/spec.md

@@ -19,6 +19,7 @@ When Umami is enabled, the site MUST support custom event emission for:
 - `outbound_click`
 - `media_preview`
 - `media_preview_close`
+- `theme_switch`
 - a general click interaction event for all instrumented clickable items (per the site tracking taxonomy)
 
 Each emitted event MUST include enough properties to segment reports by platform and placement when applicable.
@@ -63,6 +64,26 @@ For content-related links (clickables representing a specific piece of content),
 - **WHEN** a user clicks a CTA inside the media modal (e.g., "View on YouTube")
 - **THEN** the system emits a `cta_click` event with `target_id`, `placement=media_modal`, `platform`, and `target_url`
 
+### 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
+
 ### Requirement: Environment configuration
 The site MUST support configuration of Umami parameters (at minimum: website ID and script URL) without requiring code changes.