@media only screen and (min-width: 768px) {
    .nomobile {
        display: none;
    }
}

@media only screen and (max-width: 768px) {
    body {
        overflow: hidden;
    }
    
    .navbar {
        display: none;
    }

    .nomobile {
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;

        background-color: black;
        display: flex;
        align-items: center;
        justify-content: center;
    }
}