I need the red box to expand with the blue box content, so they are always both the same size.

The red box is defined as:
.leftMenu{
float:left;
width:20%;
background-image:url(../images/leftMenuBG.jpg);
background-position:bottom;
background-color:#BFDAE3;
background-repeat:repeat-x;
}
Can’t seem to get it to work, whatever I try! Any ideas? Thanks!
Simple solution: Use tables.
Semantic solution: Use faux columns.