## ADDED Requirements

### Requirement: Standard click tracking taxonomy
The system MUST define and follow a standard taxonomy for tracking user interactions (clicks) across the website.

The taxonomy MUST define:
- required event name(s)
- required event properties
- allowed values for categorical properties (where applicable)
- uniqueness rules for identifiers

#### Scenario: Adding a new tracked link
- **WHEN** a new link is added to any page/component
- **THEN** it is instrumented according to the taxonomy (required event name and required properties) without additional bespoke tracking code

### Requirement: Unique identifier for every clickable item
Every clickable item that is tracked MUST have a stable identifier (`target_id`) that is unique across the site (or unique within a documented namespace).

The identifier MUST be deterministic across builds for the same element and placement.

The taxonomy MUST define namespaces for repeated UI surfaces. For the blog surface, the following namespaces MUST be used:
- `blog.subnav.*` for secondary navigation links
- `blog.card.post.<slug>` for blog post cards
- `blog.pages.link.<slug>` for blog page listing links
- `blog.post.*` / `blog.page.*` for detail page chrome links (e.g., back links)

#### Scenario: Two links in different placements
- **WHEN** two links point to the same destination but appear in different placements
- **THEN** their `target_id` values are different so their clicks can be measured independently

### Requirement: Media preview event for in-page content views
The tracking taxonomy MUST define a `media_preview` event for content card clicks that open an in-page media modal instead of navigating outbound.

The `media_preview` event MUST include the following properties:
- `target_id` (stable unique identifier for the card, following the existing `card.{placement}.{source}.{id}` format)
- `placement` (the listing surface where the card appears, e.g., `home.newest`, `videos.list`, `podcast.list`)
- `title` (human-readable content title, truncated to max 160 characters)
- `type` (`video` or `podcast_episode`)
- `source` (`youtube` or `podcast`)

#### Scenario: Video card click emits media_preview
- **WHEN** a user clicks a YouTube video card on the videos listing page
- **THEN** the system emits a `media_preview` event with `target_id=card.videos.list.youtube.{id}`, `placement=videos.list`, `type=video`, and `source=youtube`

#### Scenario: Podcast card click emits media_preview on homepage
- **WHEN** a user clicks a podcast card in the homepage podcast section
- **THEN** the system emits a `media_preview` event with `target_id=card.home.podcast.podcast.{id}`, `placement=home.podcast`, `type=podcast_episode`, and `source=podcast`

### Requirement: Media preview close event
The tracking taxonomy MUST define a `media_preview_close` event emitted when the media modal is dismissed.

The `media_preview_close` event MUST include:
- `target_id` (the same identifier as the `media_preview` event that opened the modal)
- `close_method` (one of: `button`, `escape`, `backdrop`)

#### Scenario: User closes modal via Escape key
- **WHEN** the user presses Escape to close the media modal that was opened from a video card
- **THEN** the system emits a `media_preview_close` event with the original `target_id` and `close_method=escape`

#### Scenario: User closes modal via close button
- **WHEN** the user clicks the close button on the media modal
- **THEN** the system emits a `media_preview_close` event with the original `target_id` and `close_method=button`

#### Scenario: User closes modal via backdrop click
- **WHEN** the user clicks the backdrop outside the modal content
- **THEN** the system emits a `media_preview_close` event with the original `target_id` and `close_method=backdrop`

### Requirement: Modal CTA namespace
The tracking taxonomy MUST define a `media_modal` placement value for CTA interactions within the media modal.

Modal CTAs MUST use `target_id` values in the namespace `modal.cta.{action}.{platform}`.

The `action` value MUST be one of:
- `subscribe` (YouTube channel)
- `view` (YouTube video)
- `follow` (Spotify podcast profile)
- `listen` (Spotify episode)

#### Scenario: User clicks "View on YouTube" in modal
- **WHEN** the user clicks the "View on YouTube" CTA inside the media modal
- **THEN** the system emits a `cta_click` event with `target_id=modal.cta.view.youtube`, `placement=media_modal`, and `platform=youtube`

#### Scenario: User clicks "Subscribe on YouTube" in modal
- **WHEN** the user clicks the "Subscribe on YouTube" CTA inside the media modal
- **THEN** the system emits a `cta_click` event with `target_id=modal.cta.subscribe.youtube`, `placement=media_modal`, and `platform=youtube`

#### Scenario: User clicks "Follow on Spotify" in modal
- **WHEN** the user clicks the "Follow on Spotify" CTA inside the media modal
- **THEN** the system emits a `cta_click` event with `target_id=modal.cta.follow.spotify`, `placement=media_modal`, and `platform=spotify`

#### Scenario: User clicks "Listen on Spotify" in modal
- **WHEN** the user clicks the "Listen on Spotify" CTA inside the media modal
- **THEN** the system emits a `cta_click` event with `target_id=modal.cta.listen.spotify`, `placement=media_modal`, and `platform=spotify`

### Requirement: Minimum required properties
Every tracked click event MUST include, at minimum:
- `target_id`
- `placement`

For links, the event MUST also include:
- `target_url` (or a stable target identifier that can be mapped to a URL)

For content-related links (clickables representing a specific piece of content), the event MUST also include:
- `title` (human-readable content title)
- `type` (content type identifier)

The `type` value MUST be one of:
- `video`
- `podcast_episode`
- `blog_post`
- `blog_page`

For non-link clickables that trigger in-page actions (e.g., modal openers), the event MUST also include:
- `title` (human-readable content title)
- `type` (content type identifier)
- `source` (content source identifier)

#### Scenario: Tracking a content card click
- **WHEN** a user clicks a content card link
- **THEN** the emitted event includes `target_id`, `placement`, and `target_url`

#### Scenario: Tracking a content link includes title and type
- **WHEN** a user clicks a content-related link that represents a specific content item
- **THEN** the emitted event includes `target_id`, `placement`, `target_url`, `title`, and `type`

#### Scenario: Tracking a modal-trigger card includes title, type, and source
- **WHEN** a user clicks a content card that opens a media modal instead of navigating
- **THEN** the emitted event includes `target_id`, `placement`, `title`, `type`, and `source` (no `target_url` since the user stays on-page)

### Requirement: No PII in event properties
The taxonomy MUST prohibit including personally identifiable information (PII) in event names or event properties.

#### Scenario: Tracking includes only categorical metadata
- **WHEN** tracking metadata is defined for a clickable item
- **THEN** it contains only categorical identifiers (ids, placements, domains) and does not include user-provided content

### 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 MUST include `prev_theme` when it is 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`