Implement WinUI-style immersive overlays and migrate existing pop-ups; tweak context menus to better match WinUI styling; implement sliding pill animation

src/UniGetUI.Avalonia/Assets/Styles/Styles.WindowsMica.axaml

@@ -16,7 +16,7 @@
             <!-- Window/page surface goes transparent so Mica shows behind chrome + page -->
             <SolidColorBrush x:Key="MicaPageBackground"          Color="Transparent"/>
             <!-- Cards / panels: translucent white layers over the (light) Mica -->
-            <SolidColorBrush x:Key="SettingsCardBackground"      Color="#80FFFFFF"/>
+            <SolidColorBrush x:Key="SettingsCardBackground"      Color="#B3FFFFFF"/>
             <SolidColorBrush x:Key="SettingsCardBorderBrush"     Color="#14000000"/>
             <!-- Package list: near-transparent so Mica shows through, matching WinUI's SystemFillColorNeutralBackground -->
             <SolidColorBrush x:Key="PackageListBackground"       Color="#06000000"/>
@@ -30,7 +30,7 @@
             <SolidColorBrush x:Key="AppDialogDarkBackground"     Color="#80FFFFFF"/>
             <!-- Flyouts / menus / dropdowns / tooltips: DWM acrylic backdrop with the card tint over it -->
             <SolidColorBrush x:Key="FlyoutPresenterBackground"     Color="#80FFFFFF"/>
-            <SolidColorBrush x:Key="MenuFlyoutPresenterBackground" Color="#80FFFFFF"/>
+            <SolidColorBrush x:Key="MenuFlyoutPresenterBackground" Color="#FFFFFFFF"/>
             <SolidColorBrush x:Key="ComboBoxDropDownBackground"    Color="#80FFFFFF"/>
             <SolidColorBrush x:Key="ToolTipBackground"             Color="#80FFFFFF"/>
             <!-- Expander chrome -->
@@ -53,8 +53,8 @@
 
         <ResourceDictionary x:Key="Dark">
             <SolidColorBrush x:Key="MicaPageBackground"          Color="Transparent"/>
-            <!-- Cards / panels: translucent dark layers; ~40% so the wallpaper-tinted Mica bleeds through -->
-            <SolidColorBrush x:Key="SettingsCardBackground"      Color="#662D2D2D"/>
+            <!-- Cards / panels: WinUI's translucent card layer over the Mica backdrop -->
+            <SolidColorBrush x:Key="SettingsCardBackground"      Color="#0DFFFFFF"/>
             <SolidColorBrush x:Key="SettingsCardBorderBrush"     Color="#26FFFFFF"/>
             <!-- Package list: near-transparent so Mica shows through, matching WinUI's SystemFillColorNeutralBackground -->
             <SolidColorBrush x:Key="PackageListBackground"       Color="#08FFFFFF"/>
@@ -71,7 +71,7 @@
                  stays readably dark even when the popup floats over bright content (e.g. the release-notes
                  WebView) — a lighter tint let the white page wash the menu out (#5007) -->
             <SolidColorBrush x:Key="FlyoutPresenterBackground"     Color="#BF2D2D2D"/>
-            <SolidColorBrush x:Key="MenuFlyoutPresenterBackground" Color="#BF2D2D2D"/>
+            <SolidColorBrush x:Key="MenuFlyoutPresenterBackground" Color="#FF2C2C2C"/>
             <SolidColorBrush x:Key="ComboBoxDropDownBackground"    Color="#BF2D2D2D"/>
             <SolidColorBrush x:Key="ToolTipBackground"             Color="#BF2D2D2D"/>
             <!-- Expander chrome -->

src/UniGetUI.Avalonia/Infrastructure/MicaWindowHelper.cs

@@ -5,6 +5,7 @@
 using Avalonia.Controls.Primitives;
 using Avalonia.Media;
 using Avalonia.Platform;
+using Avalonia.VisualTree;
 using UniGetUI.Avalonia.Assets.Styles;
 
 namespace UniGetUI.Avalonia.Infrastructure;
@@ -48,22 +49,22 @@ public static void Apply(Window window)
         };
     }
 
-    // Gives flyouts / menus / combo dropdowns / tooltips a native Win11 acrylic backdrop:
-    // the popup window is made transparent and DWM paints the (blurred, theme-adaptive)
-    // acrylic material behind it. Registered once at startup when Mica is enabled.
+    // Applies the Windows 11 transient-surface treatment to popup hosts. Menus use an
+    // opaque WinUI surface; combo dropdowns, tooltips, and ordinary flyouts use acrylic.
+    // Registered once at startup when Mica is enabled.
     public static void EnableAcrylicPopups()
     {
         if (!IsMicaEnabled() || _acrylicPopupsHooked)
             return;
         _acrylicPopupsHooked = true;
 
-        // In-app flyouts/menus/tooltips/combo popups are hosted in a PopupRoot; style each as it loads.
+        // In-app menus, flyouts, tooltips, and combo popups are hosted in a PopupRoot.
         Control.LoadedEvent.AddClassHandler<PopupRoot>((root, _) => ApplyAcrylicToPopup(root));
 
         // The system-tray context menu is NOT a PopupRoot — Avalonia hosts it in its own Window
         // (Avalonia.Win32.TrayIconImpl.TrayPopupRoot), so it misses the handler above and would
-        // render with no backdrop (transparent over the desktop). Catch it by type name and apply
-        // the same acrylic treatment. The other Windows (MainWindow/dialogs) are handled via Apply().
+        // render with no surface over the desktop. Catch it by type name and apply the opaque
+        // menu treatment. The other Windows (MainWindow/dialogs) are handled via Apply().
         Control.LoadedEvent.AddClassHandler<Window>((win, _) =>
         {
             if (win.GetType().Name == "TrayPopupRoot")
@@ -76,10 +77,28 @@ private static void ApplyAcrylicToPopup(TopLevel root)
         if (!IsMicaEnabled())
             return;
 
+        // Menus use WinUI's opaque flyout surface. Other transient controls (combo boxes,
+        // tooltips and ordinary flyouts) retain acrylic.
+        bool isMenu = root.GetType().Name == "TrayPopupRoot"
+                      || root.GetVisualDescendants()
+                          .Any(control => control is MenuFlyoutPresenter or ContextMenu);
+        if (isMenu)
+        {
+            root.TransparencyLevelHint = new[] { WindowTransparencyLevel.None };
+            if (root.TryFindResource("MenuSurfaceBrush", root.ActualThemeVariant, out object? resource)
+                && resource is IBrush brush)
+            {
+                root.Background = brush;
+            }
+
+            ApplyRoundedCorners(root);
+            return;
+        }
+
         // Request acrylic (not Transparent): the Transparent level makes a layered window, and DWM
         // system backdrops never paint on those — so the popup ended up fully see-through with only
-        // the presenter tint, unreadable when shown over the desktop (e.g. the tray menu). AcrylicBlur
-        // gives a composited window DWM can actually fill. This path only runs when Mica is enabled
+        // the presenter tint and make its contents unreadable. AcrylicBlur gives a composited window
+        // DWM can actually fill. This path only runs when Mica is enabled
         // (Win11 + transparency effects), so acrylic is always available here.
         root.TransparencyLevelHint = new[] { WindowTransparencyLevel.AcrylicBlur, WindowTransparencyLevel.Blur };
         root.Background = Brushes.Transparent;
@@ -93,6 +112,15 @@ private static void ApplyAcrylicToPopup(TopLevel root)
         NativeMethods.DwmSetWindowAttribute(handle, DWMWA_SYSTEMBACKDROP_TYPE, ref backdrop, sizeof(int));
     }
 
+    private static void ApplyRoundedCorners(TopLevel root)
+    {
+        if (root.TryGetPlatformHandle()?.Handle is not { } handle || handle == 0)
+            return;
+
+        int corner = DWMWCP_ROUND;
+        NativeMethods.DwmSetWindowAttribute(handle, DWMWA_WINDOW_CORNER_PREFERENCE, ref corner, sizeof(int));
+    }
+
     /// <summary>
     /// True when the native Mica look should be used: Windows 11+, "Transparency effects" on,
     /// GPU-accelerated (software rendering can't be transparent, so Mica shows as black — #5111),

src/UniGetUI.Avalonia/Infrastructure/UninstallConfirmationDialog.cs

@@ -22,15 +22,10 @@ public static async Task<bool> ConfirmAsync(Window owner, IReadOnlyList<IPackage
         }
 
         bool isConfirmed = false;
-        var dialog = new Window
+        var dialog = new UniGetUI.Avalonia.Views.DialogPages.ImmersiveDialog
         {
-            Width = packages.Count == 1 ? 520 : 560,
-            Height = packages.Count == 1 ? 220 : 380,
-            MinWidth = 420,
-            MinHeight = packages.Count == 1 ? 220 : 300,
-            CanResize = packages.Count > 1,
-            ShowInTaskbar = false,
-            WindowStartupLocation = WindowStartupLocation.CenterOwner,
+            MaxWidth = packages.Count == 1 ? 520 : 560,
+            MaxHeight = packages.Count == 1 ? 220 : 380,
             Title = CoreTools.Translate("Are you sure?"),
         };
 

src/UniGetUI.Avalonia/ViewModels/DialogPages/ManageIgnoredUpdatesViewModel.cs

@@ -11,8 +11,6 @@ namespace UniGetUI.Avalonia.ViewModels;
 
 public partial class ManageIgnoredUpdatesViewModel : ObservableObject
 {
-    public event EventHandler? CloseRequested;
-
     public string Title { get; } = CoreTools.Translate("Manage ignored updates");
     public string Description { get; } = CoreTools.Translate("The packages listed here won't be taken in account when checking for updates. Double-click them or click the button on their right to stop ignoring their updates.");
     public string ResetLabel { get; } = CoreTools.Translate("Reset list");

src/UniGetUI.Avalonia/ViewModels/Pages/SettingsPages/BackupViewModel.cs

@@ -347,13 +347,11 @@ private static async Task RestoreFromCloud()
             Width = 360,
         };
 
-        var dialog = new Window
+        var dialog = new UniGetUI.Avalonia.Views.DialogPages.ImmersiveDialog
         {
             Title = CoreTools.Translate("Select backup"),
-            Width = 440,
-            Height = 160,
-            CanResize = false,
-            WindowStartupLocation = WindowStartupLocation.CenterOwner,
+            MaxWidth = 440,
+            MaxHeight = 160,
             Content = new StackPanel
             {
                 Margin = new Thickness(20),

src/UniGetUI.Avalonia/ViewModels/SoftwarePages/PackagesPageViewModel.cs

@@ -366,13 +366,10 @@ public async Task ShowInfoDialog(Window owner, string title, string message)
     {
         object? bgResource = null;
         Application.Current?.Resources.TryGetResource("AppWindowBackground", Application.Current.ActualThemeVariant, out bgResource);
-        var dialog = new Window
+        var dialog = new UniGetUI.Avalonia.Views.DialogPages.ImmersiveDialog
         {
-            Width = 460,
-            Height = 180,
-            CanResize = false,
-            ShowInTaskbar = false,
-            WindowStartupLocation = WindowStartupLocation.CenterOwner,
+            MaxWidth = 460,
+            MaxHeight = 180,
             Title = title,
             Background = bgResource as IBrush,
         };

src/UniGetUI.Avalonia/Views/Controls/InfoBar.axaml.cs

@@ -26,6 +26,8 @@ public InfoBar()
     }
 
     private InfoBarViewModel? _vm;
+    private IDisposable? _severityStripBinding;
+    private IDisposable? _severityIconBinding;
 
     private void OnDataContextChanged(object? sender, EventArgs e)
     {
@@ -53,24 +55,43 @@ private void ApplySeverity(InfoBarSeverity severity)
         BodyBorder.Classes.Set("severity-warning", severity == InfoBarSeverity.Warning);
         BodyBorder.Classes.Set("severity-info", severity == InfoBarSeverity.Informational);
 
-        // Strip colour (solid, not theme-sensitive)
-        var stripColor = severity switch
+        _severityStripBinding?.Dispose();
+        _severityIconBinding?.Dispose();
+        _severityStripBinding = null;
+        _severityIconBinding = null;
+
+        Color? stripColor = severity switch
         {
             InfoBarSeverity.Warning => Color.Parse("#F7A800"),
             InfoBarSeverity.Error => Color.Parse("#C42B1C"),
             InfoBarSeverity.Success => Color.Parse("#107C10"),
-            _ => Color.Parse("#0078D4"),
+            _ => null,
         };
-        SeverityStrip.Background = new SolidColorBrush(stripColor);
 
-        // Icon (shared SVG asset, tinted with the severity colour)
         SeverityIcon.Path = severity switch
         {
             InfoBarSeverity.Warning => WarningIcon,
             InfoBarSeverity.Error => ErrorIcon,
             InfoBarSeverity.Success => SuccessIcon,
             _ => InfoIcon,
         };
-        SeverityIcon.Foreground = new SolidColorBrush(stripColor);
+
+        if (stripColor is { } color)
+        {
+            var brush = new SolidColorBrush(color);
+            SeverityStrip.Background = brush;
+            SeverityIcon.Foreground = brush;
+        }
+        else
+        {
+            SeverityStrip.ClearValue(Border.BackgroundProperty);
+            SeverityIcon.ClearValue(ForegroundProperty);
+            _severityStripBinding = SeverityStrip.Bind(
+                Border.BackgroundProperty,
+                this.GetResourceObservable("SystemAccentColor"));
+            _severityIconBinding = SeverityIcon.Bind(
+                ForegroundProperty,
+                this.GetResourceObservable("SystemAccentColor"));
+        }
     }
 }

src/UniGetUI.Avalonia/Views/DialogPages/AboutWindow.axaml

@@ -1,15 +1,15 @@
-<Window xmlns="https://github.com/avaloniaui"
+<dialogs:ImmersiveDialog xmlns="https://github.com/avaloniaui"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:dialogs="using:UniGetUI.Avalonia.Views.DialogPages"
         xmlns:t="using:UniGetUI.Avalonia.MarkupExtensions"
         xmlns:about="using:UniGetUI.Avalonia.Views.Pages.AboutPages"
         x:Class="UniGetUI.Avalonia.Views.DialogPages.AboutWindow"
         Title="{t:Translate About UniGetUI}"
-        Width="700" MinWidth="500"
-        Height="600" MinHeight="400"
-        CanResize="True"
-        ShowInTaskbar="False"
-        Background="{DynamicResource AppDialogBackground}"
-        WindowStartupLocation="CenterOwner">
+        MaxWidth="700"
+        MinWidth="500"
+        MaxHeight="600"
+        MinHeight="400"
+        Background="{DynamicResource AppDialogBackground}">
 
     <TabControl x:Name="MainTabControl" Margin="8">
 
@@ -31,4 +31,4 @@
 
     </TabControl>
 
-</Window>
+</dialogs:ImmersiveDialog>

src/UniGetUI.Avalonia/Views/DialogPages/AboutWindow.axaml.cs

@@ -3,12 +3,11 @@
 
 namespace UniGetUI.Avalonia.Views.DialogPages;
 
-public partial class AboutWindow : Window
+public partial class AboutWindow : UniGetUI.Avalonia.Views.DialogPages.ImmersiveDialog
 {
     public AboutWindow()
     {
         InitializeComponent();
-        UniGetUI.Avalonia.Infrastructure.MicaWindowHelper.Apply(this);
     }
 
     protected override void OnOpened(EventArgs e)

src/UniGetUI.Avalonia/Views/DialogPages/BundleSecurityReportDialog.axaml

@@ -1,17 +1,15 @@
-<Window xmlns="https://github.com/avaloniaui"
+<dialogs:ImmersiveDialog xmlns="https://github.com/avaloniaui"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:dialogs="using:UniGetUI.Avalonia.Views.DialogPages"
         xmlns:automation="clr-namespace:Avalonia.Automation;assembly=Avalonia.Controls"
         xmlns:t="using:UniGetUI.Avalonia.MarkupExtensions"
         x:Class="UniGetUI.Avalonia.Views.DialogPages.BundleSecurityReportDialog"
         Title="{t:Translate Bundle security report}"
-        Width="580"
-        Height="420"
+        MaxWidth="580"
         MinWidth="400"
+        MaxHeight="420"
         MinHeight="300"
-        CanResize="True"
-        ShowInTaskbar="False"
-        Background="{DynamicResource AppDialogBackground}"
-        WindowStartupLocation="CenterOwner">
+        Background="{DynamicResource AppDialogBackground}">
 
     <Grid Margin="20"
           RowDefinitions="Auto,*,Auto"
@@ -42,4 +40,4 @@
 
     </Grid>
 
-</Window>
+</dialogs:ImmersiveDialog>

src/UniGetUI.Avalonia/Views/DialogPages/BundleSecurityReportDialog.axaml.cs

@@ -4,12 +4,11 @@
 
 namespace UniGetUI.Avalonia.Views.DialogPages;
 
-public partial class BundleSecurityReportDialog : Window
+public partial class BundleSecurityReportDialog : UniGetUI.Avalonia.Views.DialogPages.ImmersiveDialog
 {
     public BundleSecurityReportDialog(BundleReport report)
     {
         InitializeComponent();
-        UniGetUI.Avalonia.Infrastructure.MicaWindowHelper.Apply(this);
 
         var sb = new System.Text.StringBuilder();
         foreach (var (pkgId, entries) in report.Contents)

src/UniGetUI.Avalonia/Views/DialogPages/CrashReportWindow.axaml

@@ -1,14 +1,14 @@
-<Window xmlns="https://github.com/avaloniaui"
+<dialogs:ImmersiveDialog xmlns="https://github.com/avaloniaui"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:dialogs="using:UniGetUI.Avalonia.Views.DialogPages"
         xmlns:t="using:UniGetUI.Avalonia.MarkupExtensions"
         x:Class="UniGetUI.Avalonia.Views.DialogPages.CrashReportWindow"
         Title="{t:Translate UniGetUI – Crash Report}"
-        Width="800" MinWidth="500"
-        Height="580" MinHeight="380"
-        CanResize="True"
-        ShowInTaskbar="False"
-        Background="{DynamicResource AppDialogBackground}"
-        WindowStartupLocation="CenterOwner">
+        MaxWidth="800"
+        MinWidth="500"
+        MaxHeight="580"
+        MinHeight="380"
+        Background="{DynamicResource AppDialogBackground}">
 
     <ScrollViewer VerticalScrollBarVisibility="Auto">
         <StackPanel Margin="24,20,24,24" Spacing="16">
@@ -66,4 +66,4 @@
         </StackPanel>
     </ScrollViewer>
 
-</Window>
+</dialogs:ImmersiveDialog>

src/UniGetUI.Avalonia/Views/DialogPages/CrashReportWindow.axaml.cs

@@ -8,15 +8,14 @@
 
 namespace UniGetUI.Avalonia.Views.DialogPages;
 
-internal sealed partial class CrashReportWindow : Window
+internal sealed partial class CrashReportWindow : UniGetUI.Avalonia.Views.DialogPages.ImmersiveDialog
 {
     private readonly string _crashReport;
 
     public CrashReportWindow(string crashReport)
     {
         _crashReport = crashReport;
         InitializeComponent();
-        UniGetUI.Avalonia.Infrastructure.MicaWindowHelper.Apply(this);
         CrashReportText.Text = crashReport;
         DontSendButton.Content = CoreTools.Translate("Don't Send");
         SendButton.Content = CoreTools.Translate("Send Report");