运行效果：
代码部分：
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<style type="text/css">.father{width:300px; height:400px; background:gray;}.box1{width:100px; height:100px; background:red;}.box2{width:100px; height:100px; background:blue;float:right;}.box3{width:200px; height:100px; background:green;} .box4{width:100px; height:200px; background:yellow;float:right;}.f1{width:200; height:100px}.f2{width:200px; height:200px;}.c{margin:0 auto}
</style>
</head>
<body><div class="father c"><div class="box4">44444</div><div class="f2"><div class="f1"><div class="box2">22222</div><div class="box1">11111</div></div><div class="box3">33333</div></div></div>
</body>
</html>
