#preloader {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 9999;
    display: flex;
    justify-content: center;
    align-items: center;
}

#loading-bar {
    position: absolute;
    bottom: 0;
    left: 0;
    height: 4px;
    width: 0;
    background: #000; /* Or any color you prefer */
    transition: width 0.1s linear;
}