Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.4.7)
// Compass (v1.0.1)
// ----

$screen-md: 768px;
$screen-lg: 1100px;

// ----------------------------------------------------------------------------
// Mixins
// ----------------------------------------------------------------------------

@mixin above($size) {
  $breakpoint: false;

  @if $size == 'sm' {
    $breakpoint: $screen-md;
  } @else if $size == 'md' {
    $breakpoint: $screen-lg;
  }

  @if $breakpoint {
    @media (min-width: $breakpoint) {
      @content;
    }
  }
}

@mixin below($size) {
  $breakpoint: false;

  @if $size == 'lg' {
    $breakpoint: $screen-lg;
  } @else if $size == 'md' {
    $breakpoint: $screen-md;
  }
  
  @if $breakpoint {

    // Pull one pixel off the breakpoint
    // since we're doing a max-width query
    $breakpoint: $breakpoint - 1px;

    @media (max-width: $breakpoint) {
      @content;
    }
    
  }
}

@mixin at($size) {
  @if $size == 'sm' {
    @include below('md') {
      @content;
    }
  } @else if $size == 'md' {
    @media (min-width: $screen-md) and (max-width: ($screen-lg - 1px)) {
      @content;
    }
  } @else if $size == 'lg' {
    @include above('md') {
      @content;
    }
  }
}

/* @include above('sm') */
@include above('sm') {
  content: ""
}

/* @include above('md') */
@include above('md') {
  content: "";
}

/* @include above('lg') INVALID */
@include above('lg') {
  content: "DOES NOT OUTPUT";
}

/* @include below('lg') */
@include below('lg') {
  content: "";
}

/* @include below('md') */
@include below('md') {
  content: "";
}

/* @include below('sm') */
@include below('sm') {
  content: "DOES NOT OUTPUT";
}

/* @include at('sm') */
@include at('sm') {
  content: "";
}

/* @include at('md') */
@include at('md') {
  content: "";
}

/* @include at('lg') */
@include at('lg') {
  content: "";
}

SassMeister-output.css

/* @include above('sm') */
@media (min-width: 768px) {
  content: "";
}
/* @include above('md') */
@media (min-width: 1100px) {
  content: "";
}
/* @include above('lg') INVALID */
/* @include below('lg') */
@media (max-width: 1099px) {
  content: "";
}
/* @include below('md') */
@media (max-width: 767px) {
  content: "";
}
/* @include below('sm') */
/* @include at('sm') */
@media (max-width: 767px) {
  content: "";
}
/* @include at('md') */
@media (min-width: 768px) and (max-width: 1099px) {
  content: "";
}
/* @include at('lg') */
@media (min-width: 1100px) {
  content: "";
}