Fifteen Surefire Ways to Break Your CSS
http://www.cssnewbie.com/15-surefire-ways-to-break-your-css/

Glazebrook, Rob L.
CSS Newbie
2009

Abstract:

But as silly as it may seem, some of the biggest CSS blunders stem from the simplest of errors. Knowing what some of those errors are and remembering to look for them can save you hours of wasted labor. Here are fifteen ways I’ve found to break my CSS for sure — and fifteen things I always look for whenever I have a problem in my code.