div 	{
 	margin-left: auto;
 	margin-right: auto;
 	width: ...;
	text-align:center;
	}


div#contenu {
	width:1000px;
	height:1740px;
	background-color:#FFCC00;
	}


div#piedpage {
	width:1000px;
	height:100px;
	background-color:#000000;
	}