12.1. Validating Your CSS
I recommend validating all your external style sheets and all your HTML pages that use internal style sheets as well. It's easy to do and it's free. If you submit a page (or multiple pages) to the W3C's CSS validation service and they pass, you can put a nifty little icon like the one in Figure 12-1 on your page.
Figure 12-1. Valid CSS Badge
Figure 12-2. Main Page of W3C's CSS Validator
Scroll down this page, if necessary, and decide whether you want to download the validator ...