.logo_sciences{top:15px;left:5px;width:50px;height:auto;display:block;box-shadow: 0 4px 12px  rgba(0, 0,0, 1.7);position:absolute;} 
#back,#stop{top:15px; right:5px;width:35px;height:35px;position:fixed;border: 2px outset #3DE5D1;box-shadow: 0 4px 12px  rgba(0, 0,0, 1.7);z-index:4;}
#back:hover{cursor:pointer;box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);}	
#stop{display:none;border-radius: 10px;border: 2px inset red;box-shadow: 0 4px 12px  rgba(255, 0,0, 1.7);}
#stop:hover,#back:hover{cursor:pointer;box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);}
#les_sciences{top:25%;left:1%;width:98%;height:70%;border-radius: 10px;position:absolute;box-shadow: 0 4px 12px  rgba(0, 0,0, 1.7);background:url(./image/fond.png)no-repeat;-moz-background-size: cover;-webkit-background-size: cover;background-size: cover;box-shadow: 0 12px 8px rgba(0, 0,0, 0.7);z-index:0;} 
.sciences{top:1%;right:35%;width:60%;height:48%;position:absolute;z-index:0;} 
.div-science{vertical-align: middle;width:95%;height:auto;padding:2%;box-shadow: 0 4px 4px rgba(0,0,0, 0.5);border-radius: 10px;margin:5px;margin-left:0px;position:relative;font-size:100%;color:#196F3D; font-weight:bold;text-align:center;z-index:10;border: 4px inset #66FF00;-moz-background-size: cover;-webkit-background-size: cover;background-size: cover;}
.liste{display:none;top:2%;right:2%;width:96%;height:96%;overflow:auto;position:absolute;z-index:0;} 
.div-science:hover{cursor:pointer;background:#2ECC71;border-radius: 10px;} 
.videos{display:none;top:51%;left:1%;width:98%;height:48%;background:#66FF00;padding:0px;margin:0px;position:absolute;z-index:3;border:1px inset #66FF00;box-shadow: 0 4px 12px  rgba(0, 0,0, 1.7);}
#menu{top:0%;right:0%;width:30%;height:48%;display:inline-block;position:absolute;text-align:center;margin:2px;padding:auto;font-size:100%;z-index:111;}
.titre{width:80%;height:22%;margin-top:5%;display:inline-block;text-align:center;box-shadow: 0 2px 4px rgba(0,0,0, 2.5);border-radius: 10px;}
.titre:hover {cursor:pointer;box-shadow: 0 2px 2px rgba(0,0,0, 0.1);border: 2px outset #66FF00;}

/*