新手求救：为什么不能居中显示啊！！！
CSS代码如下：
body{ margin:0; padding:0; text-align:center;}
div#heard{ background:url(images/hd.gif) no-repeat; height:132px;}
div#pagebody{ background:url(images/content.gif) no-repeat; height:538px; padding:0 15px; }
div#footer{ background:url(images/ft.gif) no-repeat; height:100px; padding-top:30px;}
HMTL如下：
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>实例</title>
<link rel="stylesheet" type="text/css" href="ALL.css" />
</head>
<body>
<div id="heard"></div>
<div id="pagebody"></div>
<div id="footer"></div>
</body>
打开后是左对齐，哪边出错了！
[解决办法]
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>实例</title> <style> body { text-align: center; } div#main { margin-right: auto; margin-left: auto; width: 400px; vertical-align: middle; line-height: 200px; } div#heard { background: url(images/1.jpg) no-repeat; height: 132px; } div#pagebody { background: url(images/1.jpg) no-repeat; height: 538px; } div#footer { background: url(images/1.jpg) no-repeat; height: 100px; } </style></head><body> <div id='main'> <div id="heard"> </div> <div id="pagebody"> </div> <div id="footer"> </div> </div></body></html>