relevant CSS standards

There are three CSS recommendations from the W3C: CSS1, CSS2, and CSS3. Most modern browsers support a large part of CSS1 and CSS2, as well as parts of CSS3. You can find out more at If you’re curious about how well your browser supports CSS or the effect that properties have in real browsers, you can check out the CSS test suites at CSS2 and CSS3 include a number of additional selectors.