docs: public static String toHexString(int red, int green, int blue) {
      String hexColor
        = String.format("%02X%02X%02X", red, green, blue);
  
      if (hexColor.length() < 6) {
        hexColor = "000000".substring(0, 6 - hexColor.length()) + hexColor;
      }
      return hexColor;
    }