.clear{clear:both;}
#wrapper{width:800px;}
#header{width:100%;height:100px;background:red;}
.inner_wrapper{width:100%;}
#left_side_bar{width:150px;height:500px;background:cyan;float:left;}
#content{width:500px;height:500px;background:yellow;float:left;}
#right_side_bar{width:150px;height:500px;background:cyan;float:left;}
#footer{width:100%;height:100px;background:blue;}