.banner {
    overflow: hidden;
    position: relative;
}
.banner div.slide-img.banner-bg-img:after {
    display: block;
    position: absolute;
    background-image: linear-gradient(to bottom, rgba(255, 255, 255, 0) 0, #fff 150%);
    bottom: 0;
    height: 150px;
    width: 100%;
    content: '';
    z-index: 100;
}
.banner img {
    width: 100%;
}
@media only screen and (max-width: 768px) {
    .banner {
        height: 250px;
    }
    .banner>.slide-img>img {
        height: 250px;
        width: auto;
        min-width: 100%;
    }
}