red top-level property Null safety

Implementation

NBColor red = const NBColor(
    0xFFef4444,
    <String, Color>{
      "red.50 ": Color(0xfffef2f2),
      "red.100": Color(0xfffee2e2),
      "red.200": Color(0xfffecaca),
      "red.300": Color(0xfffca5a5),
      "red.400": Color(0xfff87171),
      "red.500": Color(0xFFef4444),
      "red.600": Color(0xffdc2626),
      "red.700": Color(0xffb91c1c),
      "red.800": Color(0xff991b1b),
      "red.900": Color(0xff7f1d1d),
    },
    'red');