What is the best way to determine the source of a CSS issue

Question

I have been working on a webpage. It is the first I have actually tried to design using an image and then use proper CSS layout rather than tables.

http://www.roccocammisola.com/proj/brunel/bgimage.html

I have been having issues with the shadows on either side of the main content area. Of course these are only an issue in IE. As you can see the shadow has been cut down to about 10% of its actual height.

With my relative inexperience how do I look for relevant fixes to this issue.

Any help would be very much appreciated.

Answer 1

FireBug, the most crucial tool for debugging CSS, amongst other things.

get it here