@function hex-to-rgba($hex, $alpha: 1) {
  @if type-of($hex) != 'color' {
    @error "hex-to-rgba: $hex must be a color.";
  }

  // Extract RGB values from the HEX color
  $red: red($hex);
  $green: green($hex);
  $blue: blue($hex);

  // Return RGBA color
  @return rgba($red, $green, $blue, $alpha);
}