Generated by SassMeister.com.

SassMeister-input-HTML.html

<button>Button</button>

SassMeister-input.scss

// ----
// Sass (v3.4.4)
// Compass (v1.0.1)
// ----

// My adaptation of Rem fallback mixin 
// by Karl Merkli

//====================================

// I like easy base-10 maths
$base-font-reset: 10px;

// this flag turns px output on or off
$support-legacy: true;

@function strip-unit($num) {
  @return $num / ($num * 0 + 1);
}
 
@mixin rem($property, $values...) {
  $max: length($values);
  $pxValues: '';
  $remValues: '';
 
  @for $i from 1 through $max {
    $value: strip-unit(nth($values, $i));
    $pxValues: #{$pxValues + $value*$base-font-reset/10};
 
    @if $i < $max {
      $pxValues: #{$pxValues + " "};
    }
  }
 
  @for $i from 1 through $max {
    $value: strip-unit(nth($values, $i));
    $remValues: #{$remValues + $value/10}rem;
 
    @if $i < $max {
      $remValues: #{$remValues + " "};
    }
  }
 
 @if $support-legacy {
  #{$property}: $pxValues;
 }
  #{$property}: $remValues;
}

// Usage
button {
  @include rem(padding, 10, 20, 13, 8);
}

SassMeister-output.css

button {
  padding: 10px 20px 13px 8px;
  padding: 1rem 2rem 1.3rem 0.8rem;
}

SassMeister-rendered.html

<button>Button</button>