#loading-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 9999;
    text-align: center;
}

#loading-overlay img {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}