import 'package:flutter/material.dart';

void main() => runApp(const MyApp());

class MyApp extends StatelessWidget {
  const MyApp({super.key, this.dark = true, this.useMaterial3 = true});

  final bool dark;
  final bool useMaterial3;

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      themeMode: dark ? ThemeMode.dark : ThemeMode.light,
      theme: ThemeData(
        useMaterial3: useMaterial3,
        brightness: Brightness.light,
        colorSchemeSeed: const Color(0xff6750a4),
      ),
      darkTheme: ThemeData(
        useMaterial3: useMaterial3,
        brightness: Brightness.dark,
        colorSchemeSeed: const Color(0xff6750a4),
      ),
      home: const Example(),
    );
  }
}

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

  @override
  Widget build(BuildContext context) {
    final ScrollController scrollController = ScrollController();
    final UniqueKey uniqueKey = UniqueKey();
    return Directionality(
      textDirection: TextDirection.ltr,
      child: MediaQuery(
        data: const MediaQueryData(),
        child: ScrollConfiguration(
          behavior: const ScrollBehavior().copyWith(
            scrollbars: false,
          ),
          child: PrimaryScrollController(
            controller: scrollController,
            child: RawScrollbar(
              isAlwaysShown: true,
              thumbColor: const Color(0xffff0000),
              controller: scrollController,
              child: CustomScrollView(
                primary: true,
                // scrollDirection: Axis.horizontal,
                // center: uniqueKey,
                slivers: <Widget>[
                  SliverToBoxAdapter(
                    child: Container(
                      height: 600.0,
                    ),
                  ),
                  SliverToBoxAdapter(
                    key: uniqueKey,
                    child: Container(
                      height: 600.0,
                    ),
                  ),
                  SliverToBoxAdapter(
                    child: Container(
                      height: 600.0,
                    ),
                  ),
                ],
              ),
            ),
          ),
        ),
      ),
    );
  }
}