blue top-level property Null safety

Implementation

NBColor blue = const NBColor(
    0xff3b82f6,
    <String, Color>{
      'blue.50 ': Color(0xffeff6ff),
      'blue.100': Color(0xffdbeafe),
      'blue.200': Color(0xffbfdbfe),
      'blue.300': Color(0xff93c5fd),
      'blue.400': Color(0xff60a5fa),
      'blue.500': Color(0xff3b82f6),
      'blue.600': Color(0xff2563eb),
      'blue.700': Color(0xff1d4ed8),
      'blue.800': Color(0xff1e40af),
      'blue.900': Color(0xff1e3a8a),
    },
    'blue');