CSS

<style type="text/css">
body{
	margin:10px 15px;
	font: 12px Arial, Helvetica, sans-serif;
	background:#ffe;
	}

#tudo {
	width:760px;
	}

#topo {	
	height:80px;
	background-color:#df7ddf;
	}

#principal {
	width:578px;
	background-color:#9cf;
	float:right;
	}

#navegacao {
	width:180px;
	background-color:#ffbe7d;
	float:left;
	}

#rodape {	
	height:20px;
	background-color:#b5daa2;
	clear:both;
	}

</style>

RENDERIZAÇÃO: