Content (main & widget area) Background colour

I would like to change the background colour of the content and the widget area to white so I can use a background image in the body. The issue I am having is that the content box and the widget box don’t always line-up. I tried creating a container around these two but it doesn’t seem to work. Any help would be appreciated!

The basic idea would be like this:

#content {
    background: #fff;
    border: 1px solid #ccc;
    padding: 10px 0;
    border-radius: 4px;

Add this code to Theme Options - Other - Custom CSS and tweak it accordingly.

That worked perfect, I appreciate your help!