How To Change Flutter Dropdown Background Color

import 'package:flutter/material.dart';
void main() {
  runApp(MyApp());
}
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: Homepage(),
    );
  }
}
class Homepage extends StatefulWidget {
  @override
  State<Homepage> createState() => _HomepageState();
}
class _HomepageState extends State<Homepage> {
  String? categoryValue;
  @override
  Widget build(BuildContext context) {
    return SafeArea(
        child: Scaffold(
            body: Center(
                child: Padding(
      padding: EdgeInsets.all(20),
      child: Container(
        padding: EdgeInsets.symmetric(horizontal: 20, vertical: 5),
        decoration: BoxDecoration(
            borderRadius: BorderRadius.circular(50)
                .copyWith(bottomRight: Radius.circular(0)),
            color: Colors.purple.shade100),
        child: DropdownButtonHideUnderline(
          child: DropdownButton(
              dropdownColor: Colors.purple.shade100,
              iconEnabledColor: Colors.blue,
              isExpanded: true,
              hint: Text('Select any category', style: TextStyle(fontSize: 15)),
              value: categoryValue,
              items: [
                DropdownMenuItem(
                    value: 'Sports',
                    child: Text('Sports',
                        style: TextStyle(fontSize: 15, color: Colors.black45))),
                DropdownMenuItem(
                    value: 'Tech',
                    child: Text('Tech',
                        style: TextStyle(fontSize: 15, color: Colors.black45))),
              ],
              onChanged: (val) {
                setState(() {
                  categoryValue = val.toString();
                });
              }),
        ),
      ),
    ))));
  }
}