2nd Ed, Chapter 3, Basic Widgets, Themes

I followed all the code to the end of the first part of establishing the theme and my AppBar Title text is left aligned. I added the centerTitle: true. to the AppBar Widget to fix this. see below.

     home: Scaffold(
        // TODO: Style the title
        appBar: AppBar(
          centerTitle: true,
          title: Text(
            style: theme.textTheme.headline6,