I suppose you could get by with never learning it, but I think that would be hampering yourself. While there all "languages" that kick out CSS, it is one of the core building blocks of the web space.

The basics are very easy to learn compared to Python. I would think you should be able to pick it up very quickly.

Some of the best online resources are probably:

* Mozilla Developer Network online documentation (https://developer.mozilla.org/en-US/docs/Web/CSS)

* w3schools (https://www.w3schools.com/css/)