I'm having the same problem
Here are the most common problems that people have with that exercise: http://discuss.codecademy.com/t/exercises-6-and-8-common-problems/9999
If that doesn't help you to see where your problem is then please post the following items so that I can help you troubleshoot:
<head> ... </head>element from your index.html file.
- All of your main.css file.