Any URL that doesn't resolve to a known route or model now renders a page that matches the app shell: header, sidebar, dark theme. The page explains what happened in one sentence and offers three next- step buttons — Home, Browse Videos, Watch Shorts. Previously /shorts/1 (and every other unknown URL) rendered the bare framework 404 with no header, no navigation and no theme. Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>