@function powerNumber($number, $exp) {
  $value: 1;

  @if $exp > 0 {
    @for $i from 1 through $exp {
      $value: $value * $number;
    }
  }
  @else if $exp < 0 {
    @for $i from 1 through -$exp {
      $value: $value / $number;
    }
  }

  @return $value;
}

@function colorLuminance($color) {
  $color-rgb: ("red": red($color), "green": green($color), "blue": blue($color));

  @each $name, $value in $color-rgb {
    $adjusted: 0;
    $value: $value / 255;

    @if $value < 0.03928 {
      $value: $value / 12.92;
    }
    @else {
      $value: ($value + 0.055) / 1.055;
      $value: powerNumber($value, 2);
    }

    $color-rgb: map-merge($color-rgb, ($name: $value));
  }

  @return map-get($color-rgb, "red") * 0.2126 + map-get($color-rgb, "green") * 0.7152 + map-get($color-rgb, "blue") * 0.0722;
}

@function findColorInvert($color) {
  @if colorLuminance($color) > 0.55 {
    @return rgba(#000, 0.7);
  }
  @else {
    @return #fff;
  }
}