I always tell myself that I should use backwards-compatible CSS only.

I vividly remember IE and many hacks to have css elements properly working in it…

Imho this is a reason why markdown and other rich-textual formats appeared.

Btw is there a some “w3schools” for recent CSS?

CSS has come a long way. On several sites I’ve been able to completely remove JS for things like popups, mobile menus, and open/close interactions.

The fact that modern CSS and native browser APIs can handle so much of this makes the web feel simpler and more capable at the same time.