title: custom color for different ThemeData in flutter
body: <p>I want to define a themeData for light theme and another one for dark theme.</p>
  
  <p>but my problem is that I don't know how to define my own custom color for each themeData like badgeColor, CarColor,... 
  <a href="https://i.stack.imgur.com/DuPlq.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/DuPlq.png" alt="image "></a></p>
  
  <p>I am searching alot and confused how to do that? </p>
  
  <p>any help is appreciated. </p>