I've upgraded to 3.0.0 and noticed that titleFontSize property has been removed, and textStyle property is added. so I updated my code to use textStyle: const TextStyle(fontSize: 10.0) to adapted the change, however, it doesn't seem to work, it throws out type 'TextStyle' is not a subtype of type 'Color?'. error.

By reading the 'style-3-bottom-nav-bar.widget.dart' source code, I don't think it will accept the font size as it's using DefaultTextStyle.merge to take care of color and ignore the passed in textStyle, so the fontSize will always be 12.0 and other text styles will get ignored?

I think other themes don't have this problem as they use item.textStyle.apply to include the passed-in style value(such as style-9-bottom-nav-bar.widget.dart file), do we want to fix style 3 theme issue if it's not intended, I can provide a PR if the current behavior is not intended.