.bannerimg{
    background:url(img/careers/banner.jpg) no-repeat top center;
    width:100%;
    height:15.2rem;
}
@media only screen and (max-width: 767px) {
    .bannerimg{
        background:url(img/careers/mobile/banner.jpg) no-repeat top center;
    }
}
@media only screen and (max-width: 399) {
    .bannerimg{
        background:url(img/careers/mobile/400/banner.jpg) no-repeat top center;
    }
}