@media only screen and (min-width: 769px) {
    #div-2{
        padding: 3em 0em;
    }
} 
@media only screen and (max-width: 768px) {
    #banner-principal{
        margin-top: 4em;
    }
    #div-2{
        padding: 3em 0em;
    }
    .titulo-2{
        font-size: 1.2em;
    }
}
body{
    background-color: #000;
}