Vulcan/packages/telescope-theme-base/lib/client/scss/includes/_breakpoints.scss

$grid-unit:70px;
$grid-margin:10px;
$grid-padding:15px;
$break-small:500px;

$xsmall-break: 300px;
$small-break: 600px;
$medium-break: 800px;

@mixin xsmall(){
  @media screen and (max-width: $xsmall-break) {
    @content;
  }
}

@mixin small(){
  @media screen and (max-width: $small-break) {
    @content;
  }
}
@mixin small-medium(){
  @media screen and (max-width: $medium-break) {
    @content;
  }
}
@mixin medium(){
  @media screen and (min-width: $small-break) and (max-width: $medium-break) {
    @content;
  }
}
@mixin medium-large(){
  @media screen and (min-width: $small-break) {
    @content;
  }
}
@mixin large(){
  @media screen and (min-width: $medium-break) {
    @content;
  }
}