#popup{
    position: absolute;
    top:0px;
    left:0px;
    width: 100%;
    height: 100%;
    z-index: 5;
}
#popup[class="alpha"]{opacity: 0;}

#popup>a[class="fond"]{
    position: absolute;
    top:0px;
    left:0px;
    width: 100%;
    height: 100%;
    z-index: 0;
    opacity: .8;
    background-color: black;
}