我的代码写得有问题吗？
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "[url=http://www.]http://www.[/url]"><html xmlns="[url=http://www.]http://www.[/url]">
<head>
<meta http-equiv="Content-Type" c />
<title>无标题文档</title>
<style>
html,body{
margin:0;padding:0}
body{
border:0;font:Verdana, Arial, Helvetica, sans-serif}
#container{
width:800px;margin:0;}
#head{
width:100%;margin:0;padding:0;font:Arial,Helvetica,sans-serif;font-size:18px;line-height:70px;}
#wrapper{ text-align:left; float:left;
width:100%;margin:0;}
#main{
float:left;margin:0px 150px 0px 150px;width:50%;}
#leftside{
float:left;margin:0px 650px 0px 0px;width:25%}
#rightside{
float:left;margin-left:-25%;with:25%}
#main p{font-weight:500;}
</style>
</head>
<body>
<div id="container">
<div id="head">HEAD</div>
<div id="wrapper">
<div id="main"><p>this is main part.</p>
<p>this is main part.</p>
<p>this is main part.</p>
<p>this is main part.</p></div>
</div>
<div id="leftside">this is leftside.this is leftside.this is leftside.this is leftside.this is leftside.this is leftside.this is leftside.this is leftside.this is leftside.this is leftside.this is leftside.</div>
<div id="rightside">that is rightside.that is rightside.that is rightside.that is rightside.that is rightside.that is rightside.that is rightside.that is rightside.that is rightside.that is rightside.that is rightside.</div>
<div id="footer">here goes the footer.</div>
</div>
</body>
</html>
我希望看到的是一个头（head)和下面并列的三列，分别是leftside,main,rightside但是运行后效果总归不尽如人意
能帮我看下css出了什么问题么？我觉得红色部分有点问题，但是不知道问题怎么解决
想请教一下高手．
程序代码：
