List<Color> _gradientColors = [
    const Color(0xfff44336),
    const Color(0xffba000d),
    const Color(0xff9c27b0),
    const Color(0xff6a0080),
    const Color(0xff2196f3),
    const Color(0xff0069c0),
    const Color(0xfffdd835),
    const Color(0xffc6a700)
  ];