.right-block {
    background-color: darkblue;
    color: white;
}

/* If width < 600 px */
/*  use stacked layout and hidden nav menu */
@media screen and (max-width: 599px) {
}

/* ElseIf width >= 600 px  */
/*  use tiled layout with full nav menu */
@media screen and (min-width: 600px) {
}