The color swatch to use to paint the logo, Colors.blue by default.
If for some reason the default colors are impractical, then one
of Colors.amber, Colors.red, or Colors.indigo swatches can be used.
These are Flutter's secondary colors.
In extreme cases where none of those four color schemes will work,
Colors.pink, Colors.purple, or Colors.cyan swatches can be used.
These are Flutter's tertiary colors.
final MaterialColor colors