<html>
<head> <title>淘宝 2faner</title> <style type="text/css"> .big{ width: 800px; height: 500px; background: #333; position:absolute;left: 50%; top: 50%; margin-left:-400px; margin-top: -250px;}
.small{ width: 400px; height: 200px; position: absolute; left: 50%; top: 50%; margin-left:-200px; margin-top: -100px; background: #fff; } </style> </head> <body> <div class="big"> <div class="small"> </div> </div> </body> </html>