Vanilla uses three breakpoints: one for small screens (like phones), one for medium sized screens and a third for large screens.

Setting Default value
$breakpoint-small 620px
$breakpoint-medium 768px
$breakpoint-large 1030px
$breakpoint-navigation-threshold $breakpoint-medium

Target small screens

@media screen and (max-width: $breakpoint-medium) {
    // css

Target medium screens

@media (min-width: $breakpoint-medium) and (max-width: $breakpoint-large) {
    // css

Target large screens

@media screen and (min-width: $breakpoint-large) {

Modifying the navigation threshold

The $breakpoint-navigation-threshold is the breakpoint in which the navigation switches from horizontal (large screen) navigation to a burger style menu (small screen).

If you have a large number of menu items, you may consider overriding this value to a large breakpoint so the navigation snaps to a burger menu at a larger breakpoint.