diff --git a/LanDesktopPLONDS.installer/App.axaml b/LanDesktopPLONDS.installer/App.axaml
index 61f871a..b3e4cd6 100644
--- a/LanDesktopPLONDS.installer/App.axaml
+++ b/LanDesktopPLONDS.installer/App.axaml
@@ -1,12 +1,12 @@
 <Application xmlns="https://github.com/avaloniaui"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              xmlns:theme="using:Avalonia.Themes.Fluent"
-             xmlns:fi="using:FluentIcons.Avalonia"
              x:Class="LanDesktopPLONDS.Installer.App"
              RequestedThemeVariant="Default">
   <Application.Resources>
     <ResourceDictionary>
-      <FontFamily x:Key="AppFontFamily">Inter, Segoe UI, Microsoft YaHei UI</FontFamily>
+      <FontFamily x:Key="AppFontFamily">Segoe UI, Microsoft YaHei UI</FontFamily>
+      <FontFamily x:Key="InstallerIconFontFamily">Segoe MDL2 Assets</FontFamily>
       <CornerRadius x:Key="DesignCornerRadiusMicro">2</CornerRadius>
       <CornerRadius x:Key="DesignCornerRadiusXs">4</CornerRadius>
       <CornerRadius x:Key="DesignCornerRadiusSm">4</CornerRadius>
@@ -76,10 +76,12 @@
     <Style Selector="UserControl">
       <Setter Property="FontFamily" Value="{DynamicResource AppFontFamily}" />
     </Style>
-    <Style Selector="fi|FluentIcon">
+    <Style Selector="TextBlock.installer-icon">
       <Setter Property="Foreground" Value="{DynamicResource InstallerTextPrimaryBrush}" />
+      <Setter Property="FontFamily" Value="{DynamicResource InstallerIconFontFamily}" />
       <Setter Property="VerticalAlignment" Value="Center" />
       <Setter Property="HorizontalAlignment" Value="Center" />
+      <Setter Property="TextAlignment" Value="Center" />
     </Style>
     <Style Selector="TextBlock">
       <Setter Property="Foreground" Value="{DynamicResource InstallerTextPrimaryBrush}" />
@@ -142,13 +144,13 @@
       <Setter Property="Background" Value="{DynamicResource InstallerSubtleFillBrush}" />
       <Setter Property="Foreground" Value="{DynamicResource InstallerDisabledTextBrush}" />
     </Style>
-    <Style Selector="Button.primary-command fi|FluentIcon">
+    <Style Selector="Button.primary-command TextBlock.installer-icon">
       <Setter Property="Foreground" Value="{DynamicResource InstallerOnAccentBrush}" />
     </Style>
     <Style Selector="Button.primary-command TextBlock">
       <Setter Property="Foreground" Value="{DynamicResource InstallerOnAccentBrush}" />
     </Style>
-    <Style Selector="Button.primary-command:disabled fi|FluentIcon">
+    <Style Selector="Button.primary-command:disabled TextBlock.installer-icon">
       <Setter Property="Foreground" Value="{DynamicResource InstallerDisabledTextBrush}" />
     </Style>
     <Style Selector="Button.primary-command:disabled TextBlock">
@@ -174,13 +176,13 @@
     <Style Selector="Button.secondary-command TextBlock">
       <Setter Property="Foreground" Value="{DynamicResource InstallerTextPrimaryBrush}" />
     </Style>
-    <Style Selector="Button.secondary-command fi|FluentIcon">
+    <Style Selector="Button.secondary-command TextBlock.installer-icon">
       <Setter Property="Foreground" Value="{DynamicResource InstallerTextPrimaryBrush}" />
     </Style>
     <Style Selector="Button.secondary-command:disabled TextBlock">
       <Setter Property="Foreground" Value="{DynamicResource InstallerDisabledTextBrush}" />
     </Style>
-    <Style Selector="Button.secondary-command:disabled fi|FluentIcon">
+    <Style Selector="Button.secondary-command:disabled TextBlock.installer-icon">
       <Setter Property="Foreground" Value="{DynamicResource InstallerDisabledTextBrush}" />
     </Style>
     <Style Selector="TextBox">
diff --git a/LanDesktopPLONDS.installer/InstallerStartupDiagnostics.cs b/LanDesktopPLONDS.installer/InstallerStartupDiagnostics.cs
new file mode 100644
index 0000000..aeb1e49
--- /dev/null
+++ b/LanDesktopPLONDS.installer/InstallerStartupDiagnostics.cs
@@ -0,0 +1,92 @@
+using System.Runtime.InteropServices;
+using System.Text;
+
+namespace LanDesktopPLONDS.Installer;
+
+internal static class InstallerStartupDiagnostics
+{
+    private const uint MessageBoxIconError = 0x00000010;
+    private const uint MessageBoxOk = 0x00000000;
+
+    private static int _initialized;
+    private static int _fatalMessageShown;
+
+    public static string LogPath => Path.Combine(GetLogDirectory(), "startup.log");
+
+    public static void Initialize()
+    {
+        if (Interlocked.Exchange(ref _initialized, 1) != 0)
+        {
+            return;
+        }
+
+        AppDomain.CurrentDomain.UnhandledException += (_, args) =>
+        {
+            var exception = args.ExceptionObject as Exception;
+            ReportFatal("The installer encountered an unhandled startup error.", exception);
+        };
+
+        TaskScheduler.UnobservedTaskException += (_, args) =>
+        {
+            ReportFatal("The installer encountered an unobserved background error.", args.Exception);
+            args.SetObserved();
+        };
+
+        Log("Startup diagnostics initialized.");
+    }
+
+    public static void Log(string message)
+    {
+        try
+        {
+            Directory.CreateDirectory(GetLogDirectory());
+            File.AppendAllText(
+                LogPath,
+                $"[{DateTimeOffset.Now:O}] {message}{Environment.NewLine}",
+                Encoding.UTF8);
+        }
+        catch
+        {
+            // Diagnostics must never become the reason the installer cannot start.
+        }
+    }
+
+    public static void ReportFatal(string message, Exception? exception)
+    {
+        Log(exception is null ? message : $"{message}{Environment.NewLine}{exception}");
+
+        if (!OperatingSystem.IsWindows() || Interlocked.Exchange(ref _fatalMessageShown, 1) != 0)
+        {
+            return;
+        }
+
+        try
+        {
+            var details = exception is null
+                ? message
+                : $"{message}{Environment.NewLine}{Environment.NewLine}{exception.GetType().Name}: {exception.Message}";
+            _ = MessageBox(
+                IntPtr.Zero,
+                $"{details}{Environment.NewLine}{Environment.NewLine}Log: {LogPath}",
+                "LanDesktopPLONDS Installer",
+                MessageBoxOk | MessageBoxIconError);
+        }
+        catch
+        {
+        }
+    }
+
+    private static string GetLogDirectory()
+    {
+        var root = Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData);
+        if (string.IsNullOrWhiteSpace(root))
+        {
+            root = AppContext.BaseDirectory;
+        }
+
+        return Path.Combine(root, "LanMountainDesktop", "Installer", "logs");
+    }
+
+    [DllImport("user32.dll", EntryPoint = "MessageBoxW", CharSet = CharSet.Unicode)]
+    private static extern int MessageBox(IntPtr hWnd, string text, string caption, uint type);
+}
diff --git a/LanDesktopPLONDS.installer/LanDesktopPLONDS.installer.AOT.props b/LanDesktopPLONDS.installer/LanDesktopPLONDS.installer.AOT.props
index 902609b..4c38b97 100644
--- a/LanDesktopPLONDS.installer/LanDesktopPLONDS.installer.AOT.props
+++ b/LanDesktopPLONDS.installer/LanDesktopPLONDS.installer.AOT.props
@@ -8,7 +8,14 @@
     <IncludeNativeLibrariesForSelfExtract>true</IncludeNativeLibrariesForSelfExtract>
     <EnableCompressionInSingleFile>true</EnableCompressionInSingleFile>
     <OptimizationPreference>Size</OptimizationPreference>
+    <IlcOptimizationPreference>Size</IlcOptimizationPreference>
     <PublishReadyToRun>false</PublishReadyToRun>
+    <DebuggerSupport>false</DebuggerSupport>
+    <EventSourceSupport>false</EventSourceSupport>
+    <HttpActivityPropagationSupport>false</HttpActivityPropagationSupport>
+    <InvariantGlobalization>true</InvariantGlobalization>
+    <MetadataUpdaterSupport>false</MetadataUpdaterSupport>
+    <UseSystemResourceKeys>true</UseSystemResourceKeys>
   </PropertyGroup>
 
   <PropertyGroup>
@@ -16,24 +23,11 @@
     <AvaloniaUseCompiledBindingsByDefault>true</AvaloniaUseCompiledBindingsByDefault>
   </PropertyGroup>
 
-  <ItemGroup Condition="'$(PublishAot)' == 'true'">
-    <TrimmerRootAssembly Include="Avalonia" />
-    <TrimmerRootAssembly Include="Avalonia.Desktop" />
-    <TrimmerRootAssembly Include="Avalonia.Themes.Fluent" />
-    <TrimmerRootAssembly Include="FluentIcons.Avalonia" />
-    <TrimmerRootAssembly Include="LanDesktopPLONDS.installer" />
-    <TrimmerRootAssembly Include="System.Text.Json" />
-  </ItemGroup>
-
   <Target
     Name="PrepareInstallerEmbeddedNativeLibraries"
     BeforeTargets="AssignTargetPaths"
     Condition="'$(PublishAot)' == 'true' and '$(RuntimeIdentifier)' == 'win-x64'">
     <ItemGroup>
-      <InstallerNativeLibrary
-        Include="$(PkgAvalonia_Angle_Windows_Natives)\runtimes\win-x64\native\av_libglesv2.dll"
-        CompressedName="av_libglesv2.dll.gz"
-        Condition="Exists('$(PkgAvalonia_Angle_Windows_Natives)\runtimes\win-x64\native\av_libglesv2.dll')" />
       <InstallerNativeLibrary
         Include="$(PkgHarfBuzzSharp_NativeAssets_Win32)\runtimes\win-x64\native\libHarfBuzzSharp.dll"
         CompressedName="libHarfBuzzSharp.dll.gz"
@@ -53,9 +47,6 @@
       Command="powershell -NoProfile -ExecutionPolicy Bypass -File &quot;$(MSBuildThisFileDirectory)Compress-NativeLibrary.ps1&quot; -SourcePath &quot;%(InstallerNativeLibrary.FullPath)&quot; -DestinationPath &quot;$(IntermediateOutputPath)embedded-native\$(RuntimeIdentifier)\%(InstallerNativeLibrary.CompressedName)&quot;" />
 
     <ItemGroup>
-      <EmbeddedResource
-        Include="$(IntermediateOutputPath)embedded-native\$(RuntimeIdentifier)\av_libglesv2.dll.gz"
-        LogicalName="LanDesktopPLONDS.Installer.NativeLibraries.av_libglesv2.dll.gz" />
       <EmbeddedResource
         Include="$(IntermediateOutputPath)embedded-native\$(RuntimeIdentifier)\libHarfBuzzSharp.dll.gz"
         LogicalName="LanDesktopPLONDS.Installer.NativeLibraries.libHarfBuzzSharp.dll.gz" />
@@ -68,7 +59,7 @@
   <PropertyGroup Condition="'$(PublishAot)' == 'true'">
     <SuppressTrimAnalysisWarnings>false</SuppressTrimAnalysisWarnings>
     <TrimmerSingleWarn>false</TrimmerSingleWarn>
-    <JsonSerializerIsReflectionEnabledByDefault>true</JsonSerializerIsReflectionEnabledByDefault>
+    <JsonSerializerIsReflectionEnabledByDefault>false</JsonSerializerIsReflectionEnabledByDefault>
     <IsAotCompatible>true</IsAotCompatible>
   </PropertyGroup>
 </Project>
diff --git a/LanDesktopPLONDS.installer/LanDesktopPLONDS.installer.csproj b/LanDesktopPLONDS.installer/LanDesktopPLONDS.installer.csproj
index dd44690..097b46c 100644
--- a/LanDesktopPLONDS.installer/LanDesktopPLONDS.installer.csproj
+++ b/LanDesktopPLONDS.installer/LanDesktopPLONDS.installer.csproj
@@ -20,11 +20,9 @@
 
   <ItemGroup>
     <PackageReference Include="Avalonia" />
-    <PackageReference Include="Avalonia.Angle.Windows.Natives" GeneratePathProperty="true" PrivateAssets="all" />
+    <PackageReference Include="Avalonia.Angle.Windows.Natives" ExcludeAssets="all" PrivateAssets="all" />
     <PackageReference Include="Avalonia.Desktop" />
-    <PackageReference Include="Avalonia.Fonts.Inter" />
     <PackageReference Include="Avalonia.Themes.Fluent" />
-    <PackageReference Include="FluentIcons.Avalonia" />
     <PackageReference Include="HarfBuzzSharp.NativeAssets.Win32" GeneratePathProperty="true" PrivateAssets="all" />
     <PackageReference Include="SkiaSharp.NativeAssets.Win32" GeneratePathProperty="true" PrivateAssets="all" />
     <PackageReference Include="CommunityToolkit.Mvvm" />
diff --git a/LanDesktopPLONDS.installer/NativeDependencyBootstrapper.cs b/LanDesktopPLONDS.installer/NativeDependencyBootstrapper.cs
index 4ba4890..bfec912 100644
--- a/LanDesktopPLONDS.installer/NativeDependencyBootstrapper.cs
+++ b/LanDesktopPLONDS.installer/NativeDependencyBootstrapper.cs
@@ -13,7 +13,6 @@ internal static class NativeDependencyBootstrapper
 
     private static readonly string[] NativeLibraryNames =
     [
-        "av_libglesv2.dll",
         "libHarfBuzzSharp.dll",
         "libSkiaSharp.dll"
     ];
@@ -47,7 +46,7 @@ internal static class NativeDependencyBootstrapper
         }
         catch (Exception ex)
         {
-            System.Diagnostics.Debug.WriteLine($"[NativeDependencyBootstrapper] Failed to prepare native dependencies: {ex}");
+            InstallerStartupDiagnostics.Log($"Native dependency preparation failed: {ex}");
             return false;
         }
     }
diff --git a/LanDesktopPLONDS.installer/Program.cs b/LanDesktopPLONDS.installer/Program.cs
index d68cd9a..2152afe 100644
--- a/LanDesktopPLONDS.installer/Program.cs
+++ b/LanDesktopPLONDS.installer/Program.cs
@@ -1,4 +1,5 @@
 using Avalonia;
+using Avalonia.Win32;
 
 namespace LanDesktopPLONDS.Installer;
 
@@ -7,17 +8,21 @@ public static class Program
     [STAThread]
     public static void Main(string[] args)
     {
+        InstallerStartupDiagnostics.Initialize();
         try
         {
+            InstallerStartupDiagnostics.Log("Preparing native dependencies.");
             if (!NativeDependencyBootstrapper.TryPrepare())
             {
-                System.Diagnostics.Debug.WriteLine("[Program] Failed to prepare native dependencies, but continuing...");
+                throw new InvalidOperationException("Failed to prepare native dependencies.");
             }
+
+            InstallerStartupDiagnostics.Log("Starting Avalonia desktop lifetime.");
             BuildAvaloniaApp().StartWithClassicDesktopLifetime(args);
         }
         catch (Exception ex)
         {
-            System.Diagnostics.Debug.WriteLine($"[Program] Unhandled exception: {ex}");
+            InstallerStartupDiagnostics.ReportFatal("The installer failed to start.", ex);
         }
     }
 
@@ -25,7 +30,10 @@ public static class Program
     {
         return AppBuilder.Configure<App>()
             .UsePlatformDetect()
-            .WithInterFont()
-            .LogToTrace();
+            .With(new Win32PlatformOptions
+            {
+                RenderingMode = [Win32RenderingMode.Software],
+                CompositionMode = [Win32CompositionMode.RedirectionSurface]
+            });
     }
 }
diff --git a/LanDesktopPLONDS.installer/Services/FilesPackageInstaller.cs b/LanDesktopPLONDS.installer/Services/FilesPackageInstaller.cs
index 8b6734e..4427fac 100644
--- a/LanDesktopPLONDS.installer/Services/FilesPackageInstaller.cs
+++ b/LanDesktopPLONDS.installer/Services/FilesPackageInstaller.cs
@@ -28,6 +28,7 @@ internal sealed class FilesPackageInstaller
         var sourceAppDirectory = ResolveFullPackageAppDirectory(package.ExtractDirectory, package.Version);
         var targetDeployment = BuildDeploymentDirectory(launcherRoot, package.Version);
 
+        InstallerElevation.EnsureCanInstall(launcherRoot);
         InstallerPathGuard.EnsureUsableInstallPath(launcherRoot, EstimateRequiredBytes(sourceAppDirectory));
         Directory.CreateDirectory(launcherRoot);
         await CopyLauncherRootPayloadAsync(package.ExtractDirectory, sourceAppDirectory, launcherRoot, package.Version, progress, cancellationToken)
@@ -299,7 +300,9 @@ internal sealed class FilesPackageInstaller
                 return;
             }
 
-            var startMenu = Environment.GetFolderPath(Environment.SpecialFolder.CommonStartMenu);
+            var startMenu = InstallerElevation.IsRunningElevated()
+                ? Environment.GetFolderPath(Environment.SpecialFolder.CommonStartMenu)
+                : Environment.GetFolderPath(Environment.SpecialFolder.StartMenu);
             if (string.IsNullOrWhiteSpace(startMenu))
             {
                 startMenu = Environment.GetFolderPath(Environment.SpecialFolder.StartMenu);
diff --git a/LanDesktopPLONDS.installer/Services/InstallerElevation.cs b/LanDesktopPLONDS.installer/Services/InstallerElevation.cs
new file mode 100644
index 0000000..8101302
--- /dev/null
+++ b/LanDesktopPLONDS.installer/Services/InstallerElevation.cs
@@ -0,0 +1,52 @@
+using System.Security.Principal;
+
+namespace LanDesktopPLONDS.Installer.Services;
+
+internal static class InstallerElevation
+{
+    public static bool IsRunningElevated()
+    {
+        if (!OperatingSystem.IsWindows())
+        {
+            return true;
+        }
+
+        using var identity = WindowsIdentity.GetCurrent();
+        var principal = new WindowsPrincipal(identity);
+        return principal.IsInRole(WindowsBuiltInRole.Administrator);
+    }
+
+    public static bool RequiresElevation(string installPath)
+    {
+        if (!OperatingSystem.IsWindows())
+        {
+            return false;
+        }
+
+        var fullPath = Path.GetFullPath(installPath);
+        return IsUnderSpecialFolder(fullPath, Environment.SpecialFolder.ProgramFiles)
+               || IsUnderSpecialFolder(fullPath, Environment.SpecialFolder.ProgramFilesX86)
+               || IsUnderWindowsDirectory(fullPath);
+    }
+
+    public static void EnsureCanInstall(string installPath)
+    {
+        if (RequiresElevation(installPath) && !IsRunningElevated())
+        {
+            throw new UnauthorizedAccessException(
+                "The selected installation path requires administrator permission. Restart the installer as administrator or choose a user-writable folder.");
+        }
+    }
+
+    private static bool IsUnderSpecialFolder(string fullPath, Environment.SpecialFolder folder)
+    {
+        var root = Environment.GetFolderPath(folder);
+        return !string.IsNullOrWhiteSpace(root) && InstallerPathGuard.IsSameOrChildPath(root, fullPath);
+    }
+
+    private static bool IsUnderWindowsDirectory(string fullPath)
+    {
+        var windows = Environment.GetFolderPath(Environment.SpecialFolder.Windows);
+        return !string.IsNullOrWhiteSpace(windows) && InstallerPathGuard.IsSameOrChildPath(windows, fullPath);
+    }
+}
diff --git a/LanDesktopPLONDS.installer/Services/InstallerPathGuard.cs b/LanDesktopPLONDS.installer/Services/InstallerPathGuard.cs
index ba2b7ed..50cc081 100644
--- a/LanDesktopPLONDS.installer/Services/InstallerPathGuard.cs
+++ b/LanDesktopPLONDS.installer/Services/InstallerPathGuard.cs
@@ -6,15 +6,13 @@ public static class InstallerPathGuard
 
     public static string GetDefaultInstallPath()
     {
-        var programFiles = Environment.GetFolderPath(Environment.SpecialFolder.ProgramFiles);
-        if (string.IsNullOrWhiteSpace(programFiles))
+        var localAppData = Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData);
+        if (string.IsNullOrWhiteSpace(localAppData))
         {
-            programFiles = Path.Combine(
-                Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
-                "Programs");
+            localAppData = AppContext.BaseDirectory;
         }
 
-        return Path.Combine(programFiles, ApplicationDirectoryName);
+        return Path.Combine(localAppData, "Programs", ApplicationDirectoryName);
     }
 
     public static string GetInstallPathForSelectedFolder(string selectedFolder)
diff --git a/LanDesktopPLONDS.installer/ViewModels/InstallerStepViewModel.cs b/LanDesktopPLONDS.installer/ViewModels/InstallerStepViewModel.cs
index 7879976..6c541ae 100644
--- a/LanDesktopPLONDS.installer/ViewModels/InstallerStepViewModel.cs
+++ b/LanDesktopPLONDS.installer/ViewModels/InstallerStepViewModel.cs
@@ -1,5 +1,4 @@
 using CommunityToolkit.Mvvm.ComponentModel;
-using FluentIcons.Common;
 using LanDesktopPLONDS.Installer.Models;
 
 namespace LanDesktopPLONDS.Installer.ViewModels;
@@ -7,7 +6,7 @@ namespace LanDesktopPLONDS.Installer.ViewModels;
 public sealed partial class InstallerStepViewModel(
     InstallerStepId stepId,
     string title,
-    Icon icon) : ObservableObject
+    string iconGlyph) : ObservableObject
 {
     [ObservableProperty]
     private bool _isUnlocked;
@@ -19,5 +18,5 @@ public sealed partial class InstallerStepViewModel(
 
     public string Title { get; } = title;
 
-    public Icon Icon { get; } = icon;
+    public string IconGlyph { get; } = iconGlyph;
 }
diff --git a/LanDesktopPLONDS.installer/ViewModels/MainWindowViewModel.cs b/LanDesktopPLONDS.installer/ViewModels/MainWindowViewModel.cs
index 345b817..4eb1aef 100644
--- a/LanDesktopPLONDS.installer/ViewModels/MainWindowViewModel.cs
+++ b/LanDesktopPLONDS.installer/ViewModels/MainWindowViewModel.cs
@@ -2,7 +2,6 @@ using System.Collections.ObjectModel;
 using System.Diagnostics;
 using CommunityToolkit.Mvvm.ComponentModel;
 using CommunityToolkit.Mvvm.Input;
-using FluentIcons.Common;
 using LanDesktopPLONDS.Installer.Models;
 using LanDesktopPLONDS.Installer.Services;
 using LanMountainDesktop.Shared.Contracts.Privacy;
@@ -81,11 +80,11 @@ public sealed partial class MainWindowViewModel : ObservableObject
         _privacyConsentStore = privacyConsentStore ?? new InstallerPrivacyConsentStore();
         Steps =
         [
-            new InstallerStepViewModel(InstallerStepId.Welcome, "开始安装", Icon.Play),
-            new InstallerStepViewModel(InstallerStepId.InstallLocation, "安装位置", Icon.Folder),
-            new InstallerStepViewModel(InstallerStepId.PrivacyConfirm, "数据确认", Icon.Info),
-            new InstallerStepViewModel(InstallerStepId.Deploy, "开始部署", Icon.ArrowDownload),
-            new InstallerStepViewModel(InstallerStepId.Complete, "完成安装", Icon.Circle)
+            new InstallerStepViewModel(InstallerStepId.Welcome, "开始安装", "\uE768"),
+            new InstallerStepViewModel(InstallerStepId.InstallLocation, "安装位置", "\uE838"),
+            new InstallerStepViewModel(InstallerStepId.PrivacyConfirm, "数据确认", "\uE946"),
+            new InstallerStepViewModel(InstallerStepId.Deploy, "开始部署", "\uE896"),
+            new InstallerStepViewModel(InstallerStepId.Complete, "完成安装", "\uE73E")
         ];
         SyncSteps();
         DeviceIdPreview = _privacyIdentity.GetOrCreateDeviceId();
diff --git a/LanDesktopPLONDS.installer/Views/MainWindow.axaml b/LanDesktopPLONDS.installer/Views/MainWindow.axaml
index de4fcf3..ffa6d21 100644
--- a/LanDesktopPLONDS.installer/Views/MainWindow.axaml
+++ b/LanDesktopPLONDS.installer/Views/MainWindow.axaml
@@ -1,6 +1,5 @@
 <Window xmlns="https://github.com/avaloniaui"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-        xmlns:fi="using:FluentIcons.Avalonia"
         xmlns:vm="using:LanDesktopPLONDS.Installer.ViewModels"
         x:Class="LanDesktopPLONDS.Installer.Views.MainWindow"
         x:DataType="vm:MainWindowViewModel"
@@ -62,7 +61,7 @@
     <Style Selector="Button.step-nav-item:disabled TextBlock.step-title">
       <Setter Property="Foreground" Value="{DynamicResource InstallerDisabledTextBrush}" />
     </Style>
-    <Style Selector="Button.step-nav-item:disabled fi|FluentIcon">
+    <Style Selector="Button.step-nav-item:disabled TextBlock.installer-icon">
       <Setter Property="Foreground" Value="{DynamicResource InstallerDisabledTextBrush}" />
     </Style>
     <Style Selector="Border.step-nav-selected-fill">
@@ -129,10 +128,10 @@
                   Height="28"
                   Background="{DynamicResource InstallerAccentBrush}"
                   CornerRadius="{DynamicResource DesignCornerRadiusSm}">
-            <fi:FluentIcon Icon="ArrowDownload"
-                           IconVariant="Regular"
-                           Foreground="{DynamicResource InstallerOnAccentBrush}"
-                           FontSize="16" />
+            <TextBlock Classes="installer-icon"
+                       Text="&#xE896;"
+                       Foreground="{DynamicResource InstallerOnAccentBrush}"
+                       FontSize="16" />
           </Border>
           <TextBlock Text="{Binding WindowTitle}"
                      FontSize="13"
@@ -148,16 +147,16 @@
           <Button Classes="titlebar-icon-button"
                   ToolTip.Tip="最小化"
                   Click="OnMinimizeClick">
-            <fi:FluentIcon Icon="Subtract"
-                           IconVariant="Regular"
-                           FontSize="14" />
+            <TextBlock Classes="installer-icon"
+                       Text="&#xE921;"
+                       FontSize="14" />
           </Button>
           <Button Classes="titlebar-icon-button"
                   ToolTip.Tip="关闭"
                   Click="OnCloseClick">
-            <fi:FluentIcon Icon="Dismiss"
-                           IconVariant="Regular"
-                           FontSize="14" />
+            <TextBlock Classes="installer-icon"
+                       Text="&#xE711;"
+                       FontSize="14" />
           </Button>
         </StackPanel>
       </Grid>
@@ -196,16 +195,16 @@
                           Margin="10,0">
                       <Grid Width="18"
                             VerticalAlignment="Center">
-                        <fi:FluentIcon Icon="{Binding Icon}"
-                                       IconVariant="Regular"
-                                       Foreground="{DynamicResource InstallerTextSecondaryBrush}"
-                                       FontSize="17"
-                                       IsVisible="{Binding !IsSelected}" />
-                        <fi:FluentIcon Icon="{Binding Icon}"
-                                       IconVariant="Filled"
-                                       Foreground="{DynamicResource InstallerTextPrimaryBrush}"
-                                       FontSize="17"
-                                       IsVisible="{Binding IsSelected}" />
+                        <TextBlock Classes="installer-icon"
+                                   Text="{Binding IconGlyph}"
+                                   Foreground="{DynamicResource InstallerTextSecondaryBrush}"
+                                   FontSize="17"
+                                   IsVisible="{Binding !IsSelected}" />
+                        <TextBlock Classes="installer-icon"
+                                   Text="{Binding IconGlyph}"
+                                   Foreground="{DynamicResource InstallerTextPrimaryBrush}"
+                                   FontSize="17"
+                                   IsVisible="{Binding IsSelected}" />
                       </Grid>
                       <Grid Grid.Column="1"
                             VerticalAlignment="Center">
@@ -257,9 +256,9 @@
                             Height="40"
                             Background="{DynamicResource InstallerSubtleFillBrush}"
                             CornerRadius="{DynamicResource DesignCornerRadiusMd}">
-                      <fi:FluentIcon Icon="CloudArrowDown"
-                                     IconVariant="Regular"
-                                     FontSize="20" />
+                      <TextBlock Classes="installer-icon"
+                                 Text="&#xE896;"
+                                 FontSize="20" />
                     </Border>
                     <StackPanel Grid.Column="1"
                                 Spacing="6">
@@ -302,8 +301,8 @@
                               Command="{Binding BrowseCommand}">
                         <StackPanel Orientation="Horizontal"
                                     Spacing="6">
-                          <fi:FluentIcon Icon="FolderOpen"
-                                         IconVariant="Regular" />
+                          <TextBlock Classes="installer-icon"
+                                     Text="&#xE838;" />
                           <TextBlock Text="浏览" />
                         </StackPanel>
                       </Button>
@@ -341,10 +340,10 @@
                     <Border Classes="info-panel">
                       <Grid ColumnDefinitions="Auto,*"
                             ColumnSpacing="10">
-                        <fi:FluentIcon Icon="Shield"
-                                       IconVariant="Regular"
-                                       Foreground="{DynamicResource InstallerAccentBrush}"
-                                       FontSize="18" />
+                        <TextBlock Classes="installer-icon"
+                                   Text="&#xEA18;"
+                                   Foreground="{DynamicResource InstallerAccentBrush}"
+                                   FontSize="18" />
                         <TextBlock Grid.Column="1"
                                    Text="安装器会发送匿名设备码、系统与架构信息、目标版本和请求 IP；不会上传用户名、机器名或安装目录。"
                                    Classes="muted" />
@@ -416,8 +415,8 @@
                               Command="{Binding StartInstallCommand}">
                         <StackPanel Orientation="Horizontal"
                                     Spacing="6">
-                          <fi:FluentIcon Icon="ArrowDownload"
-                                         IconVariant="Regular" />
+                          <TextBlock Classes="installer-icon"
+                                     Text="&#xE896;" />
                           <TextBlock Text="开始安装" />
                         </StackPanel>
                       </Button>
@@ -426,8 +425,8 @@
                               IsEnabled="{Binding IsInstalling}">
                         <StackPanel Orientation="Horizontal"
                                     Spacing="6">
-                          <fi:FluentIcon Icon="Dismiss"
-                                         IconVariant="Regular" />
+                          <TextBlock Classes="installer-icon"
+                                     Text="&#xE711;" />
                           <TextBlock Text="取消" />
                         </StackPanel>
                       </Button>
@@ -454,10 +453,10 @@
                             Height="40"
                             Background="{DynamicResource InstallerSubtleFillBrush}"
                             CornerRadius="{DynamicResource DesignCornerRadiusMd}">
-                      <fi:FluentIcon Icon="CheckmarkCircle"
-                                     IconVariant="Regular"
-                                     Foreground="{DynamicResource InstallerSuccessBrush}"
-                                     FontSize="22" />
+                      <TextBlock Classes="installer-icon"
+                                 Text="&#xE73E;"
+                                 Foreground="{DynamicResource InstallerSuccessBrush}"
+                                 FontSize="22" />
                     </Border>
                     <StackPanel Grid.Column="1"
                                 Spacing="12">
@@ -473,8 +472,8 @@
                               Command="{Binding LaunchCommand}">
                         <StackPanel Orientation="Horizontal"
                                     Spacing="6">
-                          <fi:FluentIcon Icon="Play"
-                                         IconVariant="Regular" />
+                          <TextBlock Classes="installer-icon"
+                                     Text="&#xE768;" />
                           <TextBlock Text="打开阑山桌面" />
                         </StackPanel>
                       </Button>
@@ -495,10 +494,10 @@
                     IsVisible="{Binding HasError}">
               <Grid ColumnDefinitions="Auto,*"
                     ColumnSpacing="10">
-                <fi:FluentIcon Icon="ErrorCircle"
-                               IconVariant="Regular"
-                               Foreground="{DynamicResource InstallerErrorBrush}"
-                               FontSize="18" />
+                <TextBlock Classes="installer-icon"
+                           Text="&#xE783;"
+                           Foreground="{DynamicResource InstallerErrorBrush}"
+                           FontSize="18" />
                 <TextBlock Grid.Column="1"
                            Text="{Binding ErrorMessage}"
                            Foreground="{DynamicResource InstallerErrorBrush}"
@@ -511,8 +510,8 @@
                     Command="{Binding BackCommand}">
               <StackPanel Orientation="Horizontal"
                           Spacing="6">
-                <fi:FluentIcon Icon="ArrowLeft"
-                               IconVariant="Regular" />
+                <TextBlock Classes="installer-icon"
+                           Text="&#xE72B;" />
                 <TextBlock Text="上一步" />
               </StackPanel>
             </Button>
@@ -522,8 +521,8 @@
               <StackPanel Orientation="Horizontal"
                           Spacing="6">
                 <TextBlock Text="下一步" />
-                <fi:FluentIcon Icon="ArrowRight"
-                               IconVariant="Regular" />
+                <TextBlock Classes="installer-icon"
+                           Text="&#xE72A;" />
               </StackPanel>
             </Button>
           </Grid>
diff --git a/LanDesktopPLONDS.installer/app.manifest b/LanDesktopPLONDS.installer/app.manifest
index 46efea9..db6b639 100644
--- a/LanDesktopPLONDS.installer/app.manifest
+++ b/LanDesktopPLONDS.installer/app.manifest
@@ -5,7 +5,7 @@
   <trustInfo xmlns="urn:schemas-microsoft-com:asm.v2">
     <security>
       <requestedPrivileges xmlns="urn:schemas-microsoft-com:asm.v3">
-        <requestedExecutionLevel level="requireAdministrator" uiAccess="false" />
+        <requestedExecutionLevel level="asInvoker" uiAccess="false" />
       </requestedPrivileges>
     </security>
   </trustInfo>
diff --git a/LanMountainDesktop.Tests/OnlineInstallerCoreTests.cs b/LanMountainDesktop.Tests/OnlineInstallerCoreTests.cs
index bb39fa3..cb208b4 100644
--- a/LanMountainDesktop.Tests/OnlineInstallerCoreTests.cs
+++ b/LanMountainDesktop.Tests/OnlineInstallerCoreTests.cs
@@ -212,6 +212,33 @@ public sealed class OnlineInstallerCoreTests : IDisposable
         Assert.ThrowsAny<Exception>(() => InstallerPathGuard.NormalizeInstallPath(path));
     }
 
+    [Fact]
+    public void InstallerPathGuard_DefaultsToUserWritableProgramsFolder()
+    {
+        var path = InstallerPathGuard.GetDefaultInstallPath();
+
+        Assert.EndsWith(Path.Combine("Programs", InstallerPathGuard.ApplicationDirectoryName), path);
+        Assert.DoesNotContain("Program Files", path, StringComparison.OrdinalIgnoreCase);
+    }
+
+    [Fact]
+    public void InstallerElevation_DetectsProtectedProgramFilesPath()
+    {
+        if (!OperatingSystem.IsWindows())
+        {
+            return;
+        }
+
+        var programFiles = Environment.GetFolderPath(Environment.SpecialFolder.ProgramFiles);
+        if (string.IsNullOrWhiteSpace(programFiles))
+        {
+            return;
+        }
+
+        Assert.True(InstallerElevation.RequiresElevation(Path.Combine(programFiles, InstallerPathGuard.ApplicationDirectoryName)));
+        Assert.False(InstallerElevation.RequiresElevation(Path.Combine(_tempRoot, InstallerPathGuard.ApplicationDirectoryName)));
+    }
+
     [Fact]
     public async Task FilesPackageInstaller_DeploysFullPackageWithCurrentMarker()
     {
diff --git a/LanMountainDesktop/ComponentSystem/ComponentRegistry.cs b/LanMountainDesktop/ComponentSystem/ComponentRegistry.cs
index d843572..cd8c9a1 100644
--- a/LanMountainDesktop/ComponentSystem/ComponentRegistry.cs
+++ b/LanMountainDesktop/ComponentSystem/ComponentRegistry.cs
@@ -116,8 +116,8 @@ public sealed class ComponentRegistry
                 "Class Schedule",
                 "CalendarDate",
                 "Date",
-                MinWidthCells: 2,
-                MinHeightCells: 4,
+                MinWidthCells: 4,
+                MinHeightCells: 3,
                 AllowStatusBarPlacement: false,
                 AllowDesktopPlacement: true,
                 ResizeMode: DesktopComponentResizeMode.Free),
diff --git a/LanMountainDesktop/Views/Components/ClassScheduleWidget.axaml.cs b/LanMountainDesktop/Views/Components/ClassScheduleWidget.axaml.cs
index dcf6457..2c2959b 100644
--- a/LanMountainDesktop/Views/Components/ClassScheduleWidget.axaml.cs
+++ b/LanMountainDesktop/Views/Components/ClassScheduleWidget.axaml.cs
@@ -683,18 +683,18 @@ public partial class ClassScheduleWidget : UserControl, IDesktopComponentWidget,
 
         var scale = ResolveScale();
         var cardRadius = ComponentChromeCornerRadiusHelper.Small();
-        var timeFontSize = Math.Clamp(11 * scale, 8, 14);
-        var courseNameFontSize = Math.Clamp(14 * scale, 10, 18);
-        var detailFontSize = Math.Clamp(11 * scale, 8, 14);
-        var progressFontSize = Math.Clamp(10 * scale, 7, 12);
+        var timeFontSize = Math.Clamp(16 * scale, 12, 22);
+        var courseNameFontSize = Math.Clamp(20 * scale, 16, 28);
+        var detailFontSize = Math.Clamp(15 * scale, 12, 20);
+        var progressFontSize = Math.Clamp(13 * scale, 10, 16);
         var cardPadding = new Thickness(
-            Math.Clamp(10 * scale, 6, 14),
-            Math.Clamp(8 * scale, 5, 12),
-            Math.Clamp(10 * scale, 6, 14),
-            Math.Clamp(8 * scale, 5, 12));
-        var timeColumnWidth = Math.Clamp(44 * scale, 30, 56);
-        var accentBarWidth = Math.Clamp(3 * scale, 2, 4);
-        var progressBarHeight = Math.Clamp(3 * scale, 2, 4);
+            Math.Clamp(14 * scale, 10, 20),
+            Math.Clamp(12 * scale, 8, 18),
+            Math.Clamp(14 * scale, 10, 20),
+            Math.Clamp(12 * scale, 8, 18));
+        var timeColumnWidth = Math.Clamp(60 * scale, 45, 80);
+        var accentBarWidth = Math.Clamp(4 * scale, 3, 6);
+        var progressBarHeight = Math.Clamp(4 * scale, 3, 6);
 
         for (var i = 0; i < _courseItems.Count; i++)
         {
@@ -894,10 +894,10 @@ public partial class ClassScheduleWidget : UserControl, IDesktopComponentWidget,
         var itemBorder = new Border
         {
             Padding = new Thickness(
-                Math.Clamp(10 * scale, 6, 14),
-                Math.Clamp(2 * scale, 1, 4),
-                Math.Clamp(10 * scale, 6, 14),
-                Math.Clamp(2 * scale, 1, 4)),
+                Math.Clamp(14 * scale, 10, 20),
+                Math.Clamp(4 * scale, 2, 6),
+                Math.Clamp(14 * scale, 10, 20),
+                Math.Clamp(4 * scale, 2, 6)),
             Background = Brushes.Transparent,
             Child = itemGrid
         };
@@ -1022,11 +1022,11 @@ public partial class ClassScheduleWidget : UserControl, IDesktopComponentWidget,
 
         HeaderGrid.ColumnSpacing = Math.Clamp(8 * scale, 4, 14);
         DateGroup.Spacing = Math.Clamp(1.5 * scale, 0.5, 3);
-        CourseListPanel.Spacing = Math.Clamp(2 * scale, 0, 6);
+        CourseListPanel.Spacing = Math.Clamp(4 * scale, 2, 8);
 
-        var dateFontByScale = Math.Clamp(28 * scale, 14, 36);
-        var weekdayFontByScale = Math.Clamp(14 * scale, 10, 18);
-        var classCountFontByScale = Math.Clamp(12 * scale, 9, 15);
+        var dateFontByScale = Math.Clamp(36 * scale, 20, 48);
+        var weekdayFontByScale = Math.Clamp(18 * scale, 14, 24);
+        var classCountFontByScale = Math.Clamp(15 * scale, 12, 20);
 
         var availableWidth = Math.Max(1, Bounds.Width - headerPadding.Left - headerPadding.Right);
         var dateGroupEstimatedWidth = dateFontByScale * 0.6 * 3 + DateGroup.Spacing * 2;