.background-presentation {
    position:fixed;
    z-index:19;
    top:0;
    left:0;
    width:100%;
    height:100%;
}

.background-presentation .background-presentation-element {
    position:absolute;
    z-index:0;
    top:0;
    left:0;
    width:100%;
    height:100%;
    display:none;
    background-size:cover;
    background-repeat:no-repeat;
    background-attachment:fixed;
    background-position:center;
}
.background-presentation #fwv-background-element-0 {
    display:block;
}