dart_curved_tabs

import 'package:flutter/material.dart';

const Color darkBlue = Color.fromARGB(255, 18, 32, 47);

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        backgroundColor: Colors.white,
        body: Row(
          children: [
            NavColumn(),
            Spacer(),
          ]
        ),
      ),
    );
  }
}

class NavColumn extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      width: 200,
      height: MediaQuery.of(context).size.height,
      color: Colors.red,
      child: Column(
        children: List.generate(
          4, (index) {
            return Column(
              
              children: [
                Container(
                  height: 20,
                  color: Colors.white,
                  child: Container(
                    decoration: const BoxDecoration(
                      color: Colors.red,
                      borderRadius: BorderRadius.only(bottomRight: Radius.circular(20))
                    )
                  )
                ),
                Container(
                  color: Colors.red,
                  child: Container(
                    margin: const EdgeInsets.only(left: 20),
                    padding: const EdgeInsets.only(top: 10, bottom: 10, left: 20),
                    decoration: const BoxDecoration(
                      color: Colors.white,
                      borderRadius: BorderRadius.only(
                        topLeft: Radius.circular(20),
                        bottomLeft: Radius.circular(20)
                      )
                    ),
                    child: Row(
                      children: const [
                        Icon(Icons.cloud),
                        SizedBox(width: 10),
                        Text('Menu Item')
                      ]
                    )
                  )
                ),
                Container(
                  height: 20,
                  color: Colors.white,
                  child: Container(
                    decoration: const BoxDecoration(
                      color: Colors.red,
                      borderRadius: BorderRadius.only(topRight: Radius.circular(20))
                    )
                  )
                ),
              ]
            );
          }
        ) 
      )
    );
  }
}