В CSS приоритет в последовательности! Чем ниже тем выше приоритет. (Без important) конечно.
Медиа запросы идут после основных.
Вот пример правильной цепочки медиа:
/** Medium devices (tablets, 544 and up sm) **/
@media (min-width: 544px) {
}
/** Medium devices (tablets, 768 and up sm) **/
@media (min-width: 768px) {
}
/** Large devices (desktops, 992px and up lg) **/
@media (min-width: 992px) {
}
/** Extra large devices (large desktops, 1200px and up xl) **/
@media (min-width: 1200px) {
}
/** **************** ****************** **************** **/
/** Large devices (desktops, less than 1200px) **/
@media (max-width: 1199px) {
}
/** Medium devices (tablets, less than 992px) **/
@media (max-width: 991px) {
}
/** Small devices (landscape phones, less than 768px) **/
@media (max-width: 767px) {
}
/** Extra small devices (portrait phones, less than 544px ) **/
@media (max-width: 543px) {
}
/** ****************** ****************** ****************** **/
/** Medium devices (tablets, 544 and up) **/
@media (min-width: 544px) and (max-width: 767px) {
}
/** Medium devices (tablets, 768px and up) **/
@media (min-width: 768px) and (max-width: 991px) {
}
/** Large devices (desktops, 992px and up) **/
@media (min-width: 992px) and (max-width: 1199px) {
}