div.left_col{float:left; width:45%;}
div.left_col_large{float:left; width:65%;}
div.left_col_small{float:left; width:30%; margin-right:4%;}
div.right_col{float:right; width:45%;}
div.right_col_small{float:right; width:30%;}
div.middle_col{float:left; width:30%;}
div.right_top{margin-bottom:20px;}
div.right_bottom{}
div.left_top{ margin-bottom:20px;}
div.left_bottom{}
div.top_col{margin-bottom:20px;}
div.bottom_col{margin-top:20px;}