div.header {
    height: 5rem;
}

div.banner {
    height: 5rem;
    overflow: hidden;
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    position: relative;
}

/* 모바일 (가로폭 480px 이하) */
@media (max-width: 480px) {
    div.banner {
        height: 6rem;
    }
}

/* 태블릿 (481px ~ 1024px) */
@media (min-width: 481px) and (max-width: 1024px) {
    div.banner {
        height: 8rem;
    }
}

/* 데스크탑 (1025px 이상) */
@media (min-width: 1025px) {
    div.banner {
        height: 10rem;
    }
}