#grand_cadre
{
	text-align:center;
	width:100%;
	background-color:red;
}

#petit_cadre_gauche
{
	float:left;
	width:48%;
	border: 4px #AAAAAA outset;	
	background-color:grey;
}

#petit_cadre_droit
{
	float:left;
	width:48%;
	border: 4px #AAAAAA outset;	
	background-color:grey;
}