#chargement {
   position:absolute; 
   top:200px;
   margin-left:-100px;
   left:375px;
   z-index:10;
   visibility:hidden;
   }
   
   #masque {
  	position: fixed;
  	background-color: black;
  	z-index:9;
  	height:1800px;
  	width:100%;
  	display:none;
  }