wagtail/client/scss/tools/_mixins.breakpoints.scss

// Based upon the fine work and thoughts from Bootstrap v4.
// Copyright 2011-2018 The Bootstrap Authors
// Copyright 2011-2018 Twitter, Inc.
// Licensed under MIT (https://github.com/twbs/bootstrap/blob/main/LICENSE)

// Media of at least the minimum breakpoint width. No query for the smallest breakpoint.
// Makes the @content apply to the given breakpoint and wider.
@mixin media-breakpoint-up($name) {
  $min: breakpoint-min($name);
  @if $min {
    @media screen and (min-width: $min) {
      @content;
    }
  } @else {
    @content;
  }
}

// Media of at most the maximum breakpoint width. No query for the largest breakpoint.
// Makes the @content apply to the given breakpoint and narrower.
@mixin media-breakpoint-down($name) {
  $max: breakpoint-max($name);
  @if $max {
    @media screen and (max-width: $max) {
      @content;
    }
  } @else {
    @content;
  }
}