Questo è un esempio puramente inventato perchè non ho basi per fare altro:

codice:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="it" xml:lang="it">
<head>
<title></title>
<meta name="description" content="" />
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<style type="text/css">
	* {
	margin:0;
	padding:0;
	}
	body {
	text-align:center;
	}
	#container {
	margin:auto;
	width:800px;/*esempio*/
	height:600px;/*esempio*/
	border:solid 1px #000;
	}
	#header {
	margin:auto;
	width:400px;/*esempio*/
	height:100px;/*esempio*/
	border:solid 1px #000;
	}
	#header div {
	float:left;
	width:50%;
	height:50%;
	background:red;
	}
	#header .color {
	background:green;
	}
</style>
</head>
<body>
<div id="container">
     <div id="header">
		 <div class="color"></div>
		 <div></div>
		 <div></div>
		 <div class="color"></div>
	 </div>
</div>
</body>
</html>