Are there any CSS validators besides jigsaw?

Are there any other CSS validation sites out there besides jigsaw?

It’s saying that conte开发者_Python百科nt: none; is incorrect, but according to the specs it should be fine.

The best online css validator that I have found is http://www.w3schools.com/site/site_validate.asp

There are also good browser plug-ins that you can use to validate your css. I recently wrote a blog post with details and links to both online and browser validators - you can go to my blog and read the post ("Validating Your Web Pages for SEO and Useability - Why You Should Do It and How") if you want more information.

Let me know if you have questions!

I just tried validating

a:after{content:none}

and it says its valid.

It's not validation per se (Firefox doesn't implement all of CSS 2.1), but Firebug's console tab can show CSS errors. Very handy for developing.