react5/src/styles/_breakpoint.scss

// Small tablets and large smartphones (landscape view)
$screen-sm-min: 576px;

// Small tablets (portrait view)
$screen-md-min: 769px;

// Tablets and small desktops
$screen-lg-min: 992px;

// Large tablets and desktops
$screen-xl-min: 1200px;

/**
 * Breakpoint mixins
 **/
// Small devices
@mixin sm {
  @media (max-width: #{$screen-sm-min}) {
    @content;
  }
}

// Medium devices
@mixin md {
  @media (min-width: #{$screen-md-min}) {
    @content;
  }
}

// Large devices
@mixin lg {
  @media (min-width: #{$screen-lg-min}) {
    @content;
  }
}

// Extra large devices
@mixin xl {
  @media (min-width: #{$screen-xl-min}) {
    @content;
  }
}

// Custom devices
@mixin rwd($screen) {
  @media (min-width: $screen+'px') {
    @content;
  }
}