.mbt_bgvid { 
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    width: 100%;
    height: 100%;
    z-index: -1; 
}

.mbt_bgvid_inner {
    width: 100%;
    height: 100%;
}

.element-background .mbt_bgvid {
    position: absolute;
}