[Widget]Color Widgetの色を16進で設定する方法

import 'package:flutter/material.dart';
void main() {
  runApp(const MyApp());
}
class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        debugShowCheckedModeBanner: false,
        home: Scaffold(
          backgroundColor: const Color(0xFFDFF1F0),
          body: Center(
            child: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: const [
                SampleText(
                  text: '16進で設定した場合',
                  color: Color(0xFF3F51B5),
                ),
                SampleText(
                  text: '16進 少し透明にする',
                  color: Color(0x553F51B5),
                ),
                SampleText(
                  text: 'RGBで設定した場合',
                  color: Color.fromRGBO(63, 81, 181, 1.0),
                ),
                SampleText(
                  text: '定数で設定した場合',
                  color: Colors.indigo,
                ),
              ],
            ),
          ),
        ));
  }
}
class SampleText extends StatelessWidget {
  const SampleText({Key? key, required this.text, required this.color})
      : super(key: key);
  final String text;
  final Color color;
  @override
  Widget build(BuildContext context) {
    return Text(
      text,
      style: TextStyle(
        color: color,
        fontSize: 30.0,
        fontWeight: FontWeight.bold,
      ),
    );
  }
}