I was going to list a whole bunch of things the DETAILS tag doesn’t allow, but it seems that none of these issues actually appear. So either it has evolved since I’ve looked at it last time or I was stupid.

Either way, thanks for talking back.

What’s a native HTML element that mimics Bootstraps Collapse?

It also has lots of UI widgets like collapsing elements, modals and alerts. Sure, you could code all these by hand, but why bother?