Is valid CSS “important”? (The jQuery UI CSS doesn’t validate.)

Question

Observe that the jQuery UI CSS does not pass validation.

I try to adhere to standards wherever I can find them. I'm looking at jQuery UI and wondering why a group of developers that makes a solid product doesn't seem to even acknowledge the W3C-imposed standards.

Is the W3C CSS Validator just too picky? Or should I pay better attention to these errors/warnings?

Is valid CSS important to adhere to? Why do you feel it's important?

Answer 1

In perfect world, yes it would be important. In reality, to make CSS look aewsome in every single browser requires some... creativity. The result is that it may not be strictly valid, but works in (for example) IE and Safari both, even they can interpret the same rules very differently.

I think HTML validation is much more important, because its your content. Screen readers or other accessibility aids depend on standardized and well structured content. But CSS is just to make things look nice. And if it looks nice every you want it be, then I would call that perfectly "valid".