/* Add custom CSS styles below */ 
body.slider_has_overlay .advanced-slider .advanced-slider__slide:before {
    background: linear-gradient(180deg, rgba(0, 0, 0, .23), transparent);
    content: "";
    height: 100%;
    left: 0;
    position: absolute;
    top: 0;
    width: 100%;
    z-index: 1;
}