This is cool! I was actually wondering about how to make this work recently and obviously did a bad job of researching it because I didn't realise it already existed[0].

One place I'd love to see this is in a classless html framework. My experience is you always wind up wanting something like cards, and then either writing classes, or having a slightly magic "use these elements in this order" incantation[1].

It would be great to have a minimal framework that peppers in a couple elements of the kind <card>, <accordian> etc.

[0] I did ask an LLM at one stage too, and it also didn't mention this behaviour exists.

[1] pico css does this.for.example for cards/accordians