```mermaid
sequenceDiagram
    participant User
    participant Engineering as Engineering Folder<br/>(priv/blog/engineering)
    participant Blogex as Blogex Library
    participant PhoenixApp as Firehose Web App
    participant Browser

    Note over User,Browser: New Markdown File Flow

    User->>Engineering: Create markdown file<br/>(e.g., new-post.md)
    
    Note over Engineering: File appears in directory
    
    Note over Blogex: Blogex reads markdown files at app startup<br/>via config (priv/blog/engineering/**/*.md)
    
    PhoenixApp->>Blogex: Request post index via BlogController<br/>(GET /blog/engineering)
    Blogex->>Engineering: Read markdown files from priv/blog/engineering/
    Blogex->>Blogex: Parse markdown + frontmatter
    Blogex->>Blogex: Create %Blogex.Post{ structs}
    
    Note over Blogex: Blogex renders HTML using its own<br/>templates in blogex/components.ex (post_index, post_show)
    
    PhoenixApp->>PhoenixApp: Render blog_html/index.html.heex (via BlogHTML)
    
    Note over PhoenixApp,Browser: Individual Post Request<br/>(GET /blog/engineering/:slug)

    Browser->>PhoenixApp: HTTP GET /blog/engineering/new-post
    PhoenixApp->>PhoenixApp: FirehoseWeb.BlogController.show
    PhoenixApp->>Blogex: Get post by slug
    Blogex->>Engineering: Read markdown file
    Blogex->>Blogex: Parse and return %Blogex.Post{}
    
    Note over Blogex: Blogex renders show_page for individual posts
    
    PhoenixApp->>PhoenixApp: Render blog_html/show.html.heex (via BlogHTML)
    PhoenixApp->>PhoenixApp: Apply FirehoseWeb.Layouts.app layout
    PhoenixApp->>PhoenixApp: Wrap with FirehoseWeb.Layouts.root layout
    
    Note over PhoenixApp: Layout provides:<br/>- Navbar (Engineering/Releases/QWAN)<br/>- Theme toggle<br/>- Global CSS (app.css with Tailwind/daisyUI)<br/>- Footer/flash messages
    
    PhoenixApp->>Browser: Return full HTML page
    
    Browser->>Browser: Render page with app styling
```