Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.3.4)
// Compass (v1.0.0.alpha.18)
// ----

// Assumptions
$base-font-size: 12px; // mobile
$base-font-size--large: 16px; // desktop
$line-height-ratio: 1.5;
$legacy-ie: false; // separate ie.scss stylesheet sets this to true

@mixin rem($property, $rem_values, $fallback: false) {
  // LEGACY IE PX FALLBACK CALCULATION
  // based off of "desktop" font size
  @if $legacy-ie == true {
    // If there's only one numeric value:
    @if type-of($rem_values) == 'number' {
      // if it's zero, no calculation or unit necessary
      @if $rem_values == 0 {
        #{$property}: $rem-values;
      } @else {
        #{$property}: $rem-values * $base-font-size--large;
      }
    }
    // If there is more than one value, create a list and perform equations on each value
    @else {
      // Create an empty list that we can dump values into
      $px_values: ();
      @each $value in $rem_values {
        // if it's zero, no calculation or unit necessary
        @if $value == 0 {
          $px_values: append($px_values, $value);
        } @else {
          $px_values: append($px_values, ($value * $base-font-size--large));
        }
      }
      // Return the property and its list of converted values
      #{$property}: $px_values;
    }
  }

  @else {
    // $fallback accepts a px value that tells it what to
    // use to measure for the fallback
    @if $fallback != false {
      // Create an empty list that we can dump values into
      $px_values: ();
      @each $value in $rem_values {
        // if it's zero, no calculation or unit necessary
        @if $value == 0 {
          $px_values: append($px_values, $value);
        } @else {
          $px_values: append($px_values, ($value * $fallback));
        }
      }
      // Return the property and its list of converted values
      #{$property}: $px_values;
    }
    
    $rem_values_with_unit: ();
    @each $value in $rem_values {
      @if $value == 0 {
        $rem_values_with_unit: append($rem_values_with_unit, $value);
      } @else {
        $rem_values_with_unit: append($rem_values_with_unit, $value + rem);
      }
    }
    #{$property}: $rem_values_with_unit;

  }
}


.heading {
  @include rem(margin-bottom, 1 0, $base-font-size);
}

SassMeister-output.css

.heading {
  margin-bottom: 12px 0;
  margin-bottom: 1rem 0;
}