I've been slowly working on my "front end" web development for a while and the critical piece to this is being able to leverage CSS better. With the ability to write mobile compatible applications as well, making CSS work for you is even more important. Fortunately, The Book of CSS3 by Peter Gasston gives you a deep and complete view of the CSS3 specification and how to make it work on your sites.
The author is quick to point out that a lot of the new hype that HTML5 demonstrations show isn't really attributed to the HTML5 specification at all, it's due to the features that CSS3 provides and that browsers are finally starting to implement. This is a key point and springboards the book into a lot of examples covering all the concepts you need when working with CSS: fonts, selectors, box effects, animations, and a lot more.
This definitely an advanced book. I consider myself an intermediate front end developer, and some of the examples involved were a little beyond my scope of knowledge. There are some assumptions the author makes (you know the difference between a div and a span, but also between bold and strong), so I had to do a little bit of digging at times to get to a fuller understanding of what is going on. However, this isn't that large of an obstacle to tackle and the additional work was worth it.
The Book of CSS3 gives you a great book in which to familiarize yourself with CSS3. It's examples are great starters to implement in your own sites, and all the topics you need are covered. I highly recommend it to add to your bookshelf of web development books.
You can get this book through O’Reilly Books at http://oreilly.com/catalog/9781593272869/.