Highly recommend svg for animations too. Totally JS-free, self-contained files, supported by all browsers but Microsoft (can just show static svg)... Once you get the hang of the syntax and svg layout, animating is pretty straightforward.

Here's a fun 404 page I made that shows just how extensive an animation you can accomplish (let it play for > 1 minute) - https://app.astronomer.io/404

(You can open the image in a new tab and take a look at the svg code (it's --pretty printed)