diff --git a/MainWindow.xaml b/MainWindow.xaml
index b4cced2..b5a23bf 100644
--- a/MainWindow.xaml
+++ b/MainWindow.xaml
@@ -39,7 +39,7 @@
         <!--  TitleBar  -->
         <Grid
             Height="{Binding ElementName=Window, Path=(ui:TitleBar.Height)}"
-            Background="#DDDDDD"
+            Background="{DynamicResource SystemControlBackgroundChromeMediumBrush}"
             DockPanel.Dock="Top">
             <Grid.Style>
                 <Style TargetType="Grid">
@@ -185,7 +185,6 @@
             <TreeView
                 Grid.Column="1"
                 MinWidth="180"
-                Background="#F3F3F3"
                 BorderThickness="0">
                 <TreeViewItem Header="Root" IsExpanded="True">
                     <TreeViewItem Header="Child1" />
@@ -219,6 +218,7 @@
                 </TabItem>
                 <TabItem Header="General" IsSelected="True">
                     <ui:SimpleStackPanel Margin="5" Spacing="10">
+                        <propertyPresenter2:PropertyPresenter2 Label="Theme Mode" Value="{Binding ThemeMode}" />
                         <propertyPresenter2:PropertyPresenter2
                             Command="{Binding ShowDialogCommand}"
                             Label="Hello"
diff --git a/ModernWpfPlayground.csproj b/ModernWpfPlayground.csproj
index 989f55f..d43d5c4 100644
--- a/ModernWpfPlayground.csproj
+++ b/ModernWpfPlayground.csproj
@@ -8,7 +8,8 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="ModernWpfUI" Version="0.8.1" />
+    <PackageReference Include="FastMember" Version="1.5.0" />
+    <PackageReference Include="ModernWpfUI" Version="0.8.2" />
     <PackageReference Include="Prism.DryIoc" Version="7.2.0.1422" />
     <PackageReference Include="Prism.Wpf" Version="7.2.0.1422" />
     <PackageReference Include="System.Drawing.Common" Version="4.7.0" />
diff --git a/MvvmStuff/BaseViewModel.cs b/MvvmStuff/BaseViewModel.cs
index 4d435ef..cddeba1 100644
--- a/MvvmStuff/BaseViewModel.cs
+++ b/MvvmStuff/BaseViewModel.cs
@@ -1,13 +1,20 @@
 using System;
 using System.Collections.Generic;
 using System.Runtime.CompilerServices;
+using FastMember;
 using Prism.Mvvm;
 
 namespace ModernWpfPlayground.MvvmStuff
 {
     public abstract class BaseViewModel : BindableBase
     {
+        protected BaseViewModel()
+        {
+            ObjectAccessor = ObjectAccessor.Create(this);
+        }
+
         private readonly Dictionary<string, object> _values = new Dictionary<string, object>();
+        protected readonly ObjectAccessor ObjectAccessor;
 
         protected IReadOnlyDictionary<string, object> Values => _values;
 
@@ -44,8 +51,7 @@ namespace ModernWpfPlayground.MvvmStuff
         {
             foreach (var (key, value) in GetViewModelItems())
             {
-                _values[key] = value!;
-                RaisePropertyChanged(key);
+                ObjectAccessor[key] = value;
             }
         }
     }
diff --git a/MvvmStuff/PropertyInfoExtension.cs b/MvvmStuff/PropertyInfoExtension.cs
index 6264ad9..36a012f 100644
--- a/MvvmStuff/PropertyInfoExtension.cs
+++ b/MvvmStuff/PropertyInfoExtension.cs
@@ -1,38 +1,35 @@
 using System;
-using System.Reflection;
 using System.Text.Json;
 
 namespace ModernWpfPlayground.MvvmStuff
 {
     public static class PropertyInfoExtension
     {
-        public static PropertyInfo? Find(this PropertyInfo[] infos, string key) => Array.Find(infos, x => x.Name == key);
-
-        public static object? Convert(this PropertyInfo? propertyInfo, JsonElement value)
+        public static object? Convert(this JsonElement value, Type propertyType)
         {
-            if (propertyInfo == null) return default;
+            if (propertyType == null) return default;
 
-            if (propertyInfo.PropertyType == typeof(double))
+            if (propertyType == typeof(double))
             {
                 return value.GetDouble();
             }
 
-            if (propertyInfo.PropertyType == typeof(bool))
+            if (propertyType == typeof(bool))
             {
                 return value.GetBoolean();
             }
 
-            if (propertyInfo.PropertyType == typeof(int))
+            if (propertyType == typeof(int))
             {
                 return value.GetInt32();
             }
 
-            if (propertyInfo.PropertyType.IsEnum)
+            if (propertyType.IsEnum)
             {
-                return Enum.ToObject(propertyInfo.PropertyType, value.GetInt32());
+                return Enum.ToObject(propertyType, value.GetInt32());
             }
 
-            if (propertyInfo.PropertyType == typeof(string))
+            if (propertyType == typeof(string))
             {
                 return value.GetString();
             }
diff --git a/ThemeMode.cs b/ThemeMode.cs
new file mode 100644
index 0000000..ac959f4
--- /dev/null
+++ b/ThemeMode.cs
@@ -0,0 +1,11 @@
+using System.ComponentModel;
+
+namespace ModernWpfPlayground
+{
+    public enum ThemeMode
+    {
+        [Description("Light")] Light,
+        [Description("Dark")] Dark,
+        [Description("Use system setting")] UseSystemSetting
+    }
+}
\ No newline at end of file
diff --git a/WindowViewModel.cs b/WindowViewModel.cs
index 7a1ec47..c17f621 100644
--- a/WindowViewModel.cs
+++ b/WindowViewModel.cs
@@ -1,11 +1,11 @@
 using System.Collections.Generic;
 using System.IO;
-using System.Reflection;
 using System.Text.Json;
 using System.Threading.Tasks;
 using System.Windows;
 using System.Windows.Input;
 using Microsoft.Win32;
+using ModernWpf;
 using ModernWpfPlayground.MvvmStuff;
 using Prism.Commands;
 
@@ -14,7 +14,6 @@ namespace ModernWpfPlayground
     public class WindowViewModel : BaseViewModel
     {
         private const string AppName = "TaBEA 3.0.0";
-        private readonly PropertyInfo[] _properties;
         private string? _path;
         private string _title = AppName;
 
@@ -29,7 +28,6 @@ namespace ModernWpfPlayground
                 ResetViewModel();
                 Path = null;
             });
-            _properties = GetType().GetProperties();
         }
 
         public string? Path
@@ -85,6 +83,23 @@ namespace ModernWpfPlayground
 
         public ICommand ResetViewModelCommand { get; }
 
+        public ThemeMode ThemeMode
+        {
+            get => GetProperty(ThemeMode.UseSystemSetting);
+            set => SetProperty(value, SetTheme);
+        }
+
+        private static void SetTheme(ThemeMode themeMode)
+        {
+            ThemeManager.Current.ApplicationTheme = themeMode switch
+            {
+                ThemeMode.Light => ApplicationTheme.Light,
+                ThemeMode.Dark => ApplicationTheme.Dark,
+                ThemeMode.UseSystemSetting => default,
+                _ => ThemeManager.Current.ApplicationTheme
+            };
+        }
+
         private async Task ShowDialogAsync()
         {
             var dialog = new ContentDialogExample {Message = WelcomeMessage};
@@ -121,7 +136,7 @@ namespace ModernWpfPlayground
             var obj = JsonSerializer.Deserialize<Dictionary<string, JsonElement>>(contents);
             foreach (var (key, value) in obj)
             {
-                yield return (key, _properties.Find(key).Convert(value));
+                yield return (key, value.Convert(ObjectAccessor[key].GetType()));
             }
         }
     }