freeCodeCamp/devdocs ? reverse-engineered prompt

Build me a fast web app for browsing API documentation in one place.

I want it to feel like DevDocs, with a clean layout, instant search, offline support, a mobile friendly view, dark mode, and full keyboard navigation. Users should be able to pick which docs they want, search across them quickly, and open pages without the interface getting cluttered. It should work well even when offline, and it should keep things lightweight and fast.

Please make the app usable right away with a polished default experience, and if you need to check current docs or best practices online, go ahead and do that. If there’s a simple way to support downloading or updating docs separately, include that too. The main goal is to make reading reference docs easy, organized, and pleasant to use.