content: import 'package:flutter/material.dart';
  
  /// Icons used in this application.
  ///
  /// Using a class for "feature" based icons used in the application makes
  /// it easy to edit them in one place if we want tho change an icons used
  /// for feature, and we have central point to maintain our app icons.
  class AppIcons {
    // This class is not meant to be instantiated or extended. This constructor
    // prevents external instantiation and extension, plus it does not show up
    // in IDE code completion. We like static classes for constants because it
    // name spaces them and gives them a self documenting group and context that
    // they belong to.
    AppIcons._();
    // The main icons we use
    static const IconData menuItemOpen = Icons.arrow_forward_ios;
    static const IconData add = Icons.add;
    static const IconData info = Icons.info;
  
    // Theme mode switch icons
    static const IconData lightTheme = Icons.wb_sunny;
    static const IconData systemTheme = Icons.phone_iphone;
    static const IconData darkTheme = Icons.bedtime;
  }
  