As a front end dev and someone who teaches front end stuff (React mainly), CSS really doesn’t change quickly, and when it does change, those changes are additive. CSS is very very good about backward compatibility.
To give a specific example, CSS Grid is a newer feature than Flexbox, but both are useful for layout, and in this case newer isn’t better, just different. (I know, newer == better is nearly a universal constant in the front end world, but CSS doesn’t suffer from that nearly as much as JS does).
I just wanted to mention this in case part of the problem is that you don’t know the “new” way to do something in CSS, and you don’t want to learn it, but you do know a way to do what you want... just do it the way you know, and it’ll very likely be fine.
You might enjoy a utility CSS framework like Tailwind [0] that relieves you from some decisions and gives you some nice shorthand without locking you in to a specific look or a specific JS framework. (I know, another thing to learn... but it’s worth a quick look, might save you time in the long run)