.conteneur {
	position:absolute;
	left: 50%;
	top: 50%;
	width: 700px;
	height: 500px;
	margin-top: -250px;
	margin-left: -350px;
	border: 0px;
} body {
	background-attachment: fixed;
	background-image:  url(../images/trame.gif);
	background-repeat: repeat;
}