CSS Page Table Shadow

I want to place the main page within a format similar to here. [login to view URL] with the grey side bars and a slight shadow around the main page to give it depth. We attempted to change the background ourselves but we couldnt figure out how to put the main wordpress page within its own table. The area between the big dark grey featured article rectangle and the home/daily commentary/about links at the top is transparent and the background shows through. I am using wordpress