@mixin checkerboard($size, $color1, $color2) {
  background:
    linear-gradient(45deg,
      $color1 25%,
      transparent 25%,
      transparent 75%,
      $color1 75%,
      $color1 0
    ),
    linear-gradient(45deg,
      $color1 25%,
      transparent 5%,
      transparent 75%,
      $color1 75%,
      $color1 0
    ),
    $color2;
  background-position: 0 0, ($size / 2) ($size / 2);
  background-size: $size $size;
  background-clip: border-box;
  background-origin: padding-box;
}