Arquivo padrão que uso nos projetos responsivos, baseado nos valores padrão do Bootstrap 3.x
/* Large devices only (large desktops) */
@media (min-width: 1200px) {
}
/* Medium devices and below (small desktops) */
@media (max-width: 1200px) {
}
/* Medium devices only (small desktops) */
@media (max-width: 1200px) and (min-width: 992px) {
}
/* Small devices and below (tablets) */
@media (max-width: 992px) {
}
/* Small devices only (tablets) */
@media (min-width: 768px) and (max-width: 992px) {
}
/* Only extra small devices (phones) */
@media (max-width: 768px) {
}