html{

    background-image: url(images/superhighway.gif);

    background-size: cover;

    overflow: hidden;

}

.overlay {

    position:fixed;

    top:0;

    left:0;

    right:0;

    bottom:0;

    background-image: url(images/data.gif);

    background-size: cover;

    opacity: 0.001;

    pointer-events: none;

    z-index:9999;

}