Back to basics, with caveats.

HTMLcat is a notebook of native HTML, CSS, and JavaScript features that are useful, easy to forget, or newly available.

Each post-it aims to answer four small questions: what does this do, why is it useful, how mature is it, and what can go wrong?

Native does not automatically mean accessible, consistent, or appropriate. Test keyboard behavior, assistive technology, reduced-motion settings, and the browsers your audience actually uses.

Found a correction or a small platform trick worth keeping? Contribute a post-it.