flutter textfield label color

TextField(
  style: TextStyle(color: Colors.red),
  decoration: InputDecoration(fillColor: Colors.orange, filled: true),
)

ThemeData( 
  // (...)
  hintStyle: TextStyle(
     color: Colors.grey, // <-- Change this
     fontSize: null,
     fontWeight: FontWeight.w400,
     fontStyle: FontStyle.normal,
     ),
);

TextField(
  style: TextStyle(color: Colors.white),
  ...
)