All the links below point to Amazon and when you click through and buy any of the books, I'll get a small commission. However this isn't the main reason I list them here. I list them here, because I've red them all and found them most helpful for every one who wants to learn CSS along with proper coding style and habits. Enjoy!
by Dave Shea and Molly E. Holzschlag
An eye-opening look at the range of design methods made possible by CSS (Cascading Style Sheets) by the creator and cultivator of the famous CSS Zen Garden Dave Shea and an instructor, web designer, and author of over 27 web design books Molly E. Holzschlag.
by Eric A. Meyer
13 hands-on projects to teach web developers how to convert an existing HTML page to CSS, how to style an events calendar, make a CSS styled input form, fix backgrounds, and create non-rectangular layout effects. It is assumed that the reader already knows the basics of CSS and HTML.
by Eric A. Meyer
The book picks up where Eric Meyer on CSS ended. It is oriented around typical design projects such as annual financial reports, weblogs, and personal homepages, and widely used design features including menus and index tabs. You can just turn to the chapter that deals with whatever you're trying to build, and see what the author did in a similar situation.
by Jeffrey Zeldman
One of the first and most well known web standards evangelist Jeffrey Zeldman explains why web standards (such as XHTML, CSS, ECMAScript, and DOM) are good for everyone, and why site designers should move towards standards compliance. The book is full of great examples and is written in typical Zeldman's style.