Flutter中TextField中标签的默认TextStyle是多少？

MaterialApp(
  theme: ThemeData(
    textTheme: TextTheme(
      subtitle1: TextStyle(
        fontSize: 16,
        color: Colors.grey,
        fontWeight: FontWeight.normal,
      ),
    ),
  ),
  // ...
)

Theme(
  data: ThemeData(
    textTheme: TextTheme(
      subtitle1: TextStyle(
        fontSize: 16,
        color: Colors.grey,
        fontWeight: FontWeight.normal,
      ),
    ),
  ),
  child: TextField(
    // ...
  ),
)