Same with anything else, you want to stick with learning principles and fundamentals over learning/memorizing how every css property works, which you can always look up.

Start with a solid understanding of selector specificity and general composition patterns. Understand the difference between block and inline-elements. Get very comfortable with devtools and use mdn as your best resource.

More than anything else, CSS gets easier with more exposure and experience through making mistakes and seeing where you went wrong or could improve. It doesn't remotely scare me anymore and there's not a CSS issue or implementation that I don't feel comfortable doing, even though every job I've had is 95% javascript.