All breakpoints are integrated in the starter theme you don't need more. (thanks @Yanis)

/* ----------- Non-Retina Screens ----------- */
@media screen
and (min-device-width: 1200px)
and (max-device-width: 1600px)
and (-webkit-min-device-pixel-ratio: 1) {
}

/* ----------- Retina Screens ----------- */
@media screen
and (min-device-width: 1200px)
and (max-device-width: 1600px)
and (-webkit-min-device-pixel-ratio: 2)
and (min-resolution: 192dpi) {
}

Existing breakpoints here : https://css-tricks.com/snippets/css/media-queries-for-standard-devices/

A compléter