.top{height:100px;background-color:#999;}
.main{height:600px;background-color:red;position:relative;}
.left{width:200px;height:600px;background-color:blue;position:absolute;}
.right{width:100%;height:600px;background-color:green;margin-left:210px;position:absolute;}
.foot{height:50px;color:}