#slider{
    width: 100%;
    background: url(/img/slider-bg.jpg);
    background-size: cover;
    background-position: center center;
    position: relative;
    z-index: 2;
    height: 50rem;
}
#slider::after{
    position: absolute;
    content: "";
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    background: #00000047;
    z-index: -1;
}