#vers_haut{
	position:fixed;
	right:10px;
	bottom:64px;
    filter: alpha(opacity = 50); /* IE < 8 */
	opacity:0.5;
	cursor: pointer;
}
	
#vers_haut:hover {
		filter: alpha(opacity = 100); /* IE < 8 */
		opacity: 1;
	}


#vers_bas{
	position:fixed;
	right:10px;
	bottom:20px;
    filter: alpha(opacity = 50); /* IE < 8 */
	opacity:0.5;
	cursor: pointer;
}
	
#vers_bas:hover {
		filter: alpha(opacity = 100); /* IE < 8 */
		opacity: 1;
	}