.overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: #000000b6;
    opacity: 0;
    /* initially hidden */
    transition: opacity 0.3s ease;
    /* smooth transition */
    opacity: 1;
}

/* .overlay:hover { */
    /* opacity: 1; */
    /* show overlay on hover */
    /* z-index: 999999; */
    /* background-color: #000000b6; */
/* } */