Detailed definitions of XHTML and CSS elements, attributes, properties, and declarations, plus examples as to how they are used. If you have a question about a given tag, etc., start here first.
Properties allow you to control the style, design, typography and more in cascading style sheets. This list is an easy to use way to get familiar with what you can do with CSS.
This site is yet another CSS reference site; but I like it because it is almost like having CSS flash cards; the information is short and sweet. However, I do find the ads annoying (too much animation) and the text renders really strangely in my browser, like it's blurred or something.
I think this is useful! It took me a minute to figure out I was on Chapter 4 (I'd like the chapter selected to show it is selected ), but the examples of the usage of the CSS is well worth a little bit of confusion.