> Moving work from JS to the browser’s native, polished, tested implementation with optimized performance is the right thing to do.

Of course, not disagreeing with that. It is just done in a way that is complex and cumbersome IMO. CSS is often handled by people with very little programming experience as well. I have worked for companies which gave me HTML templates, and CSS files, and my job as the developer was basically do add dynamic behavior by fetching stuff from their DB and looping over some data here and there to fill out lists/tables with actual content. To me that was very pleasant; but the guy handing me the CSS and HTML templates, had zero programming experience.

I think webdesign already is a copy-n-paste bonanza, where people find something they like, and copy it; if it gets very complicated as well. Developers are often last resort in terms of finding out why something does not work, and I fear complicated CSS after a few rounds of copy-n-paste is going painful to unwrap.