/* LARGE SCREENS */
@media screen and (min-width: 960px) {
    /* your css goes here */
}

/* MEDIUM SCREENS */
@media screen and (min-width: 650px) and (max-width: 959px) {
    /* your css goes here */
}

/* SMALL SCREENS */
@media screen and (max-width: 649px) {
    /* your css goes here */
}