Start with a document

The first response should be useful HTML. Navigation enhancement is optional, not a prerequisite for content or links to work.

The baseline

• Axum owns HTTP routes and status codes.
• Maud owns the document shape.
• Rust renders Markdown before it reaches the browser.
• Small JavaScript modules own browser-only behavior.

let app = Router::new().route("/", get(home));

That boundary is easy to inspect in browser developer tools and easy to test with ordinary HTTP requests.