Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.4.9)
// Compass (v1.0.1)
// ----

// ==========================================================================
// Breakpoint Mixin
// ==========================================================================

// Add or remove breakpoints as you desire
$breakpoints:(
	S: 320px,
	M: 600px,
	L: 900px,
);

@mixin breakpoint( $size ){
  @if type-of($size) == string {
  	@each $breakpoint, $value in $breakpoints {
  		@if $size == $breakpoint {
	  		@media ( min-width: map-get( $breakpoints, $breakpoint ) + 1 ) {
		  		@content;
			  }
  		}
	  	$minus: $breakpoint + "-";
		  @if $size == $minus {
		    @media ( max-width: map-get( $breakpoints, $breakpoint ) ) {
				  @content;
		    }
			}
		}
	} @else {
	  @media ( min-width: $size + 1 ) {
		  @content;
		}
	}
}

body {
  @include breakpoint( S ){
    content: S;
  }
  @include breakpoint( M ){
    content: M;
  }
  @include breakpoint( L ){
    content: L;
  }
  @include breakpoint( L- ){
    content: L-;
  }
  @include breakpoint(150px){
    content: custom;
  }
}

SassMeister-output.css

@media (min-width: 321px) {
  body {
    content: S;
  }
}
@media (min-width: 601px) {
  body {
    content: M;
  }
}
@media (min-width: 901px) {
  body {
    content: L;
  }
}
@media (max-width: 900px) {
  body {
    content: L-;
  }
}
@media (min-width: 151px) {
  body {
    content: custom;
  }
}