#principalfr {
position: relative;
text-align: center;
background-image: url("../gif/thomasdeambrosis/background.jpg");
margin: auto;
margin-top: 50px;
width: 902px;
height: 524px;
}
#principaluk {
position: relative;
text-align: center;
background-image: url("../gif/thomasdeambrosis/background_eng.jpg");
margin: auto;
margin-top: 50px;
width: 902px;
height: 524px;
}