为什么我代码弄出来的布局和老师不一样？
<html>
<head>
<title>布局</title>
<style type="text/css">
body{margin:0;padding:0}
.top{height:100px;background:blue}
.head{height:100px;wideth:800px;background:#ddd;margin:0 auto}
.main{width:800px;height:600px;background:#900;margin:0 auto}
.left{width:200px;height:600px;background:#ccc;float:left}
.right{width:600px;height:600px;;background:#ddd;float:left}
.sub_l{width:400px;height:600px;background:green;float:left}
.sub_r{width:200px;height:600px;background:#ccc;float:right}
.foot{width:800px;height:100px;background:blue;margin:0 auto}
</style>
</head>
<body>
<div class="top">
<div class="head"></div>
</div>
<div class="main">
<div class="left"></div>
<div class="right">
<div class="sub_l"></div>
<div class="sub_r"></div>
</div>
<div class="foot"></div>
</body>
</html>
