如何在保证左侧固定宽，右侧自适应的情况下，把左边绿色多出来的去掉？
另外为何在浏览器中body还是有margin，不是清0了吗
<!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>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>混合布局编程挑战</title>
<style type="text/css">
.body{ margin:0; padding:0; font-size:30px; color:#fff}
.top{background:#ccc;height:100px;margin:0 auto;}
.main{background:red;height:400px;width: 100%;}
.left{background:blue;height:400px;width:200px;float:left;}
.right{background:green;height:380px;position:absolute;margin-left:208px;margin-right:0;width:100%;}
.foot{background:orange;margin:0 auto;clear:both;}
</style>
</head>
<body>
<div class="top">top</div>
<div class="main">
<div class="right">right-----------</div>
<div class="left">left</div>
</div>
<div class="foot">foot</div>
</body>
</html>
