<!DOCTYPE html>
<html>
<meta name="name" content="content" charset='utf-8'>
<head>
<title></title>
</head>
<style type="text/css" media="screen">
.main{width: 100%;height: 400px;background: red;float: left;}
.main .in{margin: 0 200px 0 180px;background: yellow;height: 350px;}
.left{float: left;width:180px;height: 300px;background: green;margin-left:-100%;}
.right{float: left;width: 200px;height: 300px;background: blue;margin-left: -200px;}
</style>
<body>
<div class="by">
<div class="main">
<div class="in">
</div>
</div>
<div class="left">
</div>
<div class="right">
</div>
</div>
</body>
<script type="text/javascript" charset="utf-8" async defer>
</script>
</html>
