That's absurd. They are a set of rules that dictate how a browser lays out media. That's a programming language to everyone but a computer science purist. The question of whether I can use these layout rules to find the 2,000th digit of pi is totally irrelevant.

I regard them as instructions to be processed by something which can actually evaluate those instructions, like a browser. Writing css and html is no more programming than writing a word doc is. The resulting file has information and layout but it's totally static.

I wouldn't call them a language, and they're the main part of my job.