I want to change the color using the ThemeData, here is the code:

import 'package:flutter/material.dart';

ThemeData lightMode = ThemeData(
  colorScheme: ColorScheme.light(
    background: Colors.grey.shade300,
    primary: Colors.grey.shade500,
    secondary: Colors.grey.shade200,
    tertiary: Colors.white,
    inversePrimary: Colors.grey.shade900,
  ),
);

But the code from ThemeData is not applying,

My Main Page:

import 'package:flutter/material.dart';

class IntroPage extends StatelessWidget {
  const IntroPage({super.key});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Theme.of(context).colorScheme.background,
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Icon(
              Icons.trolley,
              size: 72,
              color: Theme.of(context).colorScheme.inversePrimary,
            )
          ],
        ),
      ),
    );
  }
}

This is The Result: