CSS files can be difficult to visualise particularly when some elements are nested. A page of text is just that but a picture paints a thousand words. I have found a very neat little tool that lets you visualise CSS files in pictorial, flow chart type of format. Here’s the link: CSS Poster 

It’s free of course!

This comes from the creators of HTML Kit, a very nice HTML editor. It is much more than just a HTML editor though and the basic version is free: HTML Editor from HTMLKit.Com