.conteneur {
position:absolute;
left: 50%; 
top: 50%;
width: 1000px;
height: 588px;
margin-top: -294px;
margin-left: -500px;
border: 0px solid #000000;
}
.conteneur_temp {
position:absolute;
left: 50%; 
top: 50%;
width: 1024px;
height: 700px;
margin-top: -350px;
margin-left: -512px;
border: 0px solid #000000;
}