<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<style>
body{
margin: 0;
}
.box{
width: 500px;
}
.left{
width: 200px;
height: 200px;
background-color: red;
float: left;
}
.right{
width: 200px;
height: 200px;
background-color: blue;
<!--margin-left:200px 不建议这么写-->
}
</style>
<!--
解决方案：
1、不建议这么写
2、用浮动解决
-->
</head>
<body>
<div class="box">
<div class="left"></div>
<div class="right"></div>
</div>
</body>
</html>