Grey Blocks

Like the frontpage, how can I get "mainbody" widget area to display a grey background on other pages on the site?

When I add a widget to the mainbody widget area it has a white background. I'd like to have the various color shade blocks like the frontpage on each of our pages.

Hi,

Mainbody widget area may be used only on the frontpage, could you provide an URL to your site when your want to have the gray background? (here or via PM)