#portal {
    position: fixed;
    left: 0;
    top: 0;
    width: 100vw;
    height: 100vh;
    overflow: auto;
    background-color: #ffffff;
    z-index: 9999;
    display: block;
    transform: translateZ(1000px);
}

#portal:empty {
    display: none !important;
}