#imagelightbox-overlay {
    background: rgba(255, 255, 255, .9);
    bottom: 0;
    left: 0;
    position: fixed;
    right: 0;
    top: 0;
    z-index: 9998;
    animation: fade-in .25s linear;
}

@keyframes fade-in {
    0% {
        opacity: 0;
    }
    100% {
        opacity: 1;
    }
}