Single-file interactive app generator

The prompt

Build a single self-contained HTML file that implements {{app_idea}}. Inline all CSS and JS, no external dependencies or build step, and make sure it runs by itself when opened directly in a browser.

Expected result

One complete HTML file — open it and the app just works, with no missing imports, no console errors, and no setup step.

Why it works

Explicitly banning external dependencies is what keeps the output paste-and-run instead of something that silently fails the moment a CDN script or import is blocked.