符合"渐进增强"标准+栅格理论，同时兼容性也不错，几乎没有到用hack
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<style type="text/css">
*{padding:0;margin:0}
div.page{background:#efefef;width:950px;margin:0 auto;}
div.main{width:100%;background:pink;float:left}
div.sub{width:230px;float:left;margin-left:-950px;background:lightblue;}
div.extra{width:190px;float:left;margin-left:-190px;background:lightgreen;}
div.main .main_container{margin:0 200px 0 240px;background:#f6c}
</style>
</head>
<body>
<div class="page">
<div class="main">
<div class="main_container" >main container<br/>asdfa</div>
</div>
<div class="sub">sub columne</div>
<div class="extra">extra column</div>
</div>
</body>
</html>
