@media (max-width: 960px) {
    .box{
        background: blue;
    }
    .box::before{
        content: "Bredde 768px";
     }
}
@media (max-width: 768px) {
    .box{
        background: green;
    }
    .box::before{
        content: "Bredde 480px";
     }
}
@media (max-width: 480px) {
    .box{
        background: orange;
    }
    .box::before{
        content: "Bredde low";
     }
}