accentColor property Null safety
The foreground color for widgets (knobs, text, overscroll edge effect, etc).
Accent color is also known as the secondary color.
The theme's colorScheme property contains ColorScheme.secondary, as well as a color that contrasts well with the secondary color called ColorScheme.onSecondary. It might be simpler to just configure an app's visuals in terms of the theme's colorScheme.
final Color accentColor;