title: Change the default light grey background color
body: <p>By default, every screen I created in react-native project use a very light grey color as its background color. As you see here:</p>
  <p><a href="https://i.stack.imgur.com/mUqEH.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/mUqEH.png" alt="enter image description here" /></a></p>
  <p>I wonder instead of I set <code>backgroundColor</code> for each screen of my project, is there a global place in react-native project that I can set the <code>backgroundColor</code> once for all screens in my project? For example, I would like all my screens use blue color as background color.</p>