html,
body {
    margin:0; padding:0; height:100%;
}
p {
    margin:0;
}
.page {
    position: relative;
    height:100%;
}

.popup {
    position:absolute;
    z-index:2;
    top:0;
    left:0;
    width:100%;
    height:100%;
    background:rgba(0,0,0,0.7);
    opacity:0;
    visibility:hidden;
    transition:.3s ease;
}

.show-popup .popup {
    opacity:1;
    visibility: visible;    
}

.popup > iframe {
    position:absolute;
    top:50px;
    left:50%;
    margin-left:-280px;
}