I’ve been trying to get the background to extend the height of the page content. there are a number of hacks for this but here is an elegant solution that works for me:
Add the highlighted overflow section to the div in question i.e. main:
#main {
clear: both;
padding: 1.625em 0 0;
overflow: hidden;
}
I use this in a number of wordpress themes and it seems to work well.