Is it possible "extend" ThemeData in Flutter : <p>I might very well be missing something as I'm so new to flutter, but I'm finding ThemeData's options very limited (at least with my understanding of how to implement it). </p>

<p>If you look at this random design below from MaterialUp, I'd want to model something <em>roughly</em> like: </p>

<p><code>
Themedata.cyclingColor = Color.pink;
ThemeData.runningColor = Color.green;
</code></p>

<p>That way everywhere in my app I can reference cycling, running, swimming, gym colors (Or whatever colors make sense in the context of my app/design) and keep things consistent.</p>

<p><a href="https://i.stack.imgur.com/HEgVW.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/HEgVW.jpg" alt="Random design from MaterialUp"></a></p>

<p>Is there a recommended way to achieve this currently in Flutter? What are my options? </p>
