.home-principale { border:2px solid #ccc; background: rgb(0, 0, 0); opacity: 1; background-size: cover; min-height: 400px; } @media screen and (max-width: 600px) { .home-principale { border:2px solid #ccc; background: rgb(0, 0, 0); opacity: 1; background-size: cover; min-height: 180px; } }