Flutter – The named Parameters are not defined error

Here is my code ,it is showing errors like The named parameter
‘accentColor’ isn’t defined.Try correcting the name to an existing named parameter’s name, or defining a named parameter with the name ‘accentColor’.and the same with parameter ‘brightness’.

  import 'package:flutter/material.dart';
    // import 'package:rangkings/config/config.dart';    
    // import '../config/config.dart';
    
    class ThemeModel {
      final lightMode = ThemeData(
        primarySwatch: Colors.blue,
        primaryColor: Color(0xFF3A52BC),
        accentColor: Colors.white,
        iconTheme: IconThemeData(color: Colors.white),
        fontFamily: 'Manrope',
        scaffoldBackgroundColor: Colors.white,
        brightness: Brightness.light,
        primaryColorDark: Colors.grey[800],
        primaryColorLight: Colors.white,
        secondaryHeaderColor: Colors.grey[600],
        shadowColor: Colors.grey[200],
        backgroundColor: Colors.white,
        appBarTheme: AppBarTheme(
          brightness: Brightness.light,
          color: Color(0xFF3A52BC),
          elevation: 0,
          iconTheme: IconThemeData(
            // color: Colors.grey[900],
            color: Colors.white,
          ),
          actionsIconTheme: IconThemeData(color: Colors.grey[900]),
          // textTheme: TextTheme(
          //   headline6: TextStyle(
          //     fontFamily: 'Manrope',
          //     fontSize: 18,
          //     fontWeight: FontWeight.w700,
          //     // color: Colors.grey[900],
          //     color: Colors.white,
          //   ),
          // ),
        ),
        textTheme: TextTheme(
          subtitle1: TextStyle(
              fontWeight: FontWeight.w500, fontSize: 16, color: Colors.grey[900]),
          bodyText2: TextStyle(
              fontWeight: FontWeight.w500, fontSize: 16, color: Colors.grey[900]),
        ),
        bottomNavigationBarTheme: BottomNavigationBarThemeData(
          backgroundColor: Colors.white,
          selectedItemColor: Color(0xFF3A52BC),
          unselectedItemColor: Colors.grey[500],
        ),
      );
    
      final darkMode = ThemeData(
          primarySwatch: Colors.deepPurple,
          primaryColor: Color(0xFF3A52BC),
          accentColor: Colors.white,
          iconTheme: IconThemeData(color: Colors.white),
          fontFamily: 'Manrope',
          scaffoldBackgroundColor: Color(0xff303030),
          brightness: Brightness.dark,
          primaryColorDark: Colors.grey[300],
          primaryColorLight: Colors.grey[800],
          secondaryHeaderColor: Colors.grey[400],
          shadowColor: Color(0xff282828),
          backgroundColor: Colors.grey[900],
          appBarTheme: AppBarTheme(
            brightness: Brightness.dark,
            color: Colors.grey[900],
            elevation: 0,
            iconTheme: IconThemeData(
              color: Colors.white,
            ),
            actionsIconTheme: IconThemeData(color: Colors.white),
            // textTheme: TextTheme(
            //   headline6: TextStyle(
            //     fontFamily: 'Manrope',
            //     fontSize: 18,
            //     fontWeight: FontWeight.w700,
            //     color: Colors.white,
            //   ),
            // ),
          ),
          textTheme: TextTheme(
            subtitle1: TextStyle(
                fontWeight: FontWeight.w500, fontSize: 16, color: Colors.white),
          ),
          bottomNavigationBarTheme: BottomNavigationBarThemeData(
            backgroundColor: Colors.grey[900],
            selectedItemColor: Colors.white,
            unselectedItemColor: Colors.grey[500],
          ));
    }

Give an efficient solution for this errors,only those 4 errors are showing 2 accentColor one’s and 2 brightness.