境界線のある部分をすべての画面解像度の中央に配置したい。これはmargin-topとmargin-bottomプロパティで可能ですか?
HTML:
<!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>
<link rel="stylesheet" type="text/css" href="style.css" />
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Simple Site</title>
</head>
<body>
<div id="container">
<div id="body">
<img src="2.png" width="1000" height="100" />
<center>
    <ul class="navbar">
        <li><a href="index.html">Home</a></li><li><a href="about.html">About</a></li><li><a href="contact.html">Contact</a></li><li><a href="services.html">Services</a></li><li><a href="biography.html">Biography</a></li>
    </ul>
</center>
</div>    
</div>
</body>
</html>
CSS:
@charset "utf-8";
html {
    text-align: center
}
#container {
    margin-left:auto;
    margin-right:auto;
    margin-top:50 auto;
    margin-bottom:50 auto;
    width:960px;
    background-color:#666666;
}
    #body {
        background-color:#666666;
        width:1000px;
        height:1000px;
        border:3px solid #FFFFFF;
        margin-top:50px auto;
    }
    .navbar {
        margin:0px;
        background-color:#66FF33;
        text-align:center;
        list-style:none;
        border-bottom:none;
        padding-left:0px;    
    }
    ul.navbar li {
        width:20%;
        display:inline-block;
    }
    ul.navbar a {
        display:block;
        width:100%;
        margin:0px;
        padding:10px 0px;
        text-decoration:none;
    }
    ul.navbar a:hover {
        background-color:#33FFD7;
    }
    body {
        background-color:#333333;
    }