I recently questioned someone about this very subject. They wanted to hire a "CSS expert" because the "developer" didn't have a grasp of css after having developed the project in JS/HTML. I was so confused as to how that's possible.
I suck at CSS and do a lot of js/html, but most of my work is on the back end. I can do ok with CSS but it will definitely take me longer than someone who knows what they're doing. Usually we contract out the design/CSS for a few pages and I adopt that for the rest of the website.
CSS is not consistent and complete like a programming language. As someone else mentioned, doing things the correct way in CSS (responsive, cross-browser) is actually very hard, and often requires memorizing weird hacks.
