You must have something else that's gone wrong for that to happen, but to find the background color setting for that area, go to your Admin CP >> Style Manager. Find the style you're using (if you have more than one) and make sure it says "All Style Options" then click GO >> Scroll down all the way to the bottom portion of the page.
You must have something else that's gone wrong for that to happen, but to find the background color setting for that area, go to your Admin CP >> Style Manager. Find the style you're using (if you have more than one) and make sure it says "All Style Options" then click GO >> Scroll down all the way to the bottom portion of the page.