.banner-inner{
    background: url("/static/images/banner/banner-cases.jpg") no-repeat;
    background-size: 100% 100%;
}

@media screen and (max-width:768px){
    .banner-inner{
        background: url("/static/images/banner/banner-cases-sm.jpg") no-repeat;
        background-size: 100% 100%;
    }
}