$sizeUnit: rem;
$marginKey: "m";
$paddingKey: "p";
$separator: "-";
$sizes: (("0", 0), ("xxs", 0.125), ("xs", 0.25), ("sm", 0.5), ("md", 1), ("lg", 2), ("xl", 4), ("xxl", 8));
$positions: (("t", "top"), ("r", "right"), ("b", "bottom"), ("l", "left"), ("x", "x"), ("y", "y"), ("a", "around"));

@function sizeValue($key, $value) {
  @return if($key == "0", 0, $value + $sizeUnit);
}

@each $size in $sizes {
  $sizeKey: nth($size, 1);
  $sizeValue: nth($size, 2);
  .#{$marginKey}#{$separator}#{$sizeKey} {
    margin: sizeValue($sizeKey, $sizeValue);
  }
  .#{$paddingKey}#{$separator}#{$sizeKey} {
    padding: sizeValue($sizeKey, $sizeValue);
  }
  @each $position in $positions {
    $posKey: nth($position, 1);
    $posValue: nth($position, 2);
    .#{$marginKey}#{$posKey}#{$separator}#{$sizeKey} {
      @if $posValue == "x" {
        margin-left: sizeValue($sizeKey, $sizeValue);
        margin-right: sizeValue($sizeKey, $sizeValue);
      } @else if $posValue == "y" {
        margin-top: sizeValue($sizeKey, $sizeValue);
        margin-bottom: sizeValue($sizeKey, $sizeValue);
      } @else if $posValue == "around" {
        margin: sizeValue($sizeKey, $sizeValue);
      } @else {
        margin-#{$posValue}: sizeValue($sizeKey, $sizeValue);
      }
    }
    .#{$paddingKey}#{$posKey}#{$separator}#{$sizeKey} {
      @if $posValue == "x" {
        padding-left: sizeValue($sizeKey, $sizeValue);
        padding-right: sizeValue($sizeKey, $sizeValue);
      } @else if $posValue == "y" {
        padding-top: sizeValue($sizeKey, $sizeValue);
        padding-bottom: sizeValue($sizeKey, $sizeValue);
      } @else if $posValue == "around" {
        padding: sizeValue($sizeKey, $sizeValue);
      } @else {
        padding-#{$posValue}: sizeValue($sizeKey, $sizeValue);
      }
    }
  }
}