three column layouts

Three column layouts can be tricky. The problem arises from content that doesn't fit the allowable space.

Here is the css for purl bee a three column layout.

#canvasWrapper { width: 986px; padding: 0 0px 0 0px; }  

#sidebar1Wrapper { display: block; float: left;  width: 180px; padding: 0; padding-right: 53px; } 
#sidebar2Wrapper { display: block; float: right; width: 240px; padding: 0; } 
#contentWrapper { float: left; width: 460px;  }