title: How to apply theme on MaterialButton or RaisedButton?
body: <p>Can someone help to point how do we define base theme for button and use it on every button? Everywhere I look only found <code>textTheme</code> but not <code>buttonTheme</code> example?</p>
  
  <p>Even on <code>buttonTheme</code> how do we define text colors? 
  Because on the button itself we can do it directly like <code>color: Colors.blue</code></p>