Merge remote-tracking branch 'origin/master' into msbuild-version-property

samples/ControlCatalog/App.xaml

@@ -26,8 +26,6 @@
           <Color x:Key="CatalogBaseHighColor">#FFFFFFFF</Color>
         </ResourceDictionary>
       </ResourceDictionary.ThemeDictionaries>
-      <Color x:Key="SystemAccentColor">#FF0078D7</Color>
-      <Color x:Key="SystemAccentColorDark1">#FF005A9E</Color>
 
       <!-- Styles attached dynamically depending on current theme (simple or fluent) -->
       <StyleInclude x:Key="DataGridFluent" Source="avares://Avalonia.Controls.DataGrid/Themes/Fluent.xaml" />

samples/ControlCatalog/MainView.xaml.cs

@@ -19,13 +19,9 @@ namespace ControlCatalog
 {
     public class MainView : UserControl
     {
-        private readonly IPlatformSettings _platformSettings;
-
         public MainView()
         {
             AvaloniaXamlLoader.Load(this);
-            _platformSettings = AvaloniaLocator.Current.GetRequiredService<IPlatformSettings>();
-            PlatformSettingsOnColorValuesChanged(_platformSettings, _platformSettings.GetColorValues());
             
             var sideBar = this.Get<TabControl>("Sidebar");
 
@@ -141,50 +137,6 @@ namespace ControlCatalog
                     ViewModel.IsSystemBarVisible = insets.IsSystemBarVisible ?? true;
                 };
             }
-
-            _platformSettings.ColorValuesChanged += PlatformSettingsOnColorValuesChanged;
-            PlatformSettingsOnColorValuesChanged(_platformSettings, _platformSettings.GetColorValues());
-        }
-
-        protected override void OnDetachedFromLogicalTree(LogicalTreeAttachmentEventArgs e)
-        {
-            base.OnDetachedFromLogicalTree(e);
-            
-            _platformSettings.ColorValuesChanged -= PlatformSettingsOnColorValuesChanged;
-        }
-
-        private void PlatformSettingsOnColorValuesChanged(object? sender, PlatformColorValues e)
-        {
-            Application.Current!.Resources["SystemAccentColor"] = e.AccentColor1;
-            Application.Current.Resources["SystemAccentColorDark1"] = ChangeColorLuminosity(e.AccentColor1, -0.3);
-            Application.Current.Resources["SystemAccentColorDark2"] = ChangeColorLuminosity(e.AccentColor1, -0.5);
-            Application.Current.Resources["SystemAccentColorDark3"] = ChangeColorLuminosity(e.AccentColor1, -0.7);
-            Application.Current.Resources["SystemAccentColorLight1"] = ChangeColorLuminosity(e.AccentColor1, 0.3);
-            Application.Current.Resources["SystemAccentColorLight2"] = ChangeColorLuminosity(e.AccentColor1, 0.5);
-            Application.Current.Resources["SystemAccentColorLight3"] = ChangeColorLuminosity(e.AccentColor1, 0.7);
-
-            static Color ChangeColorLuminosity(Color color, double luminosityFactor)
-            {
-                var red = (double)color.R;
-                var green = (double)color.G;
-                var blue = (double)color.B;
-
-                if (luminosityFactor < 0)
-                {
-                    luminosityFactor = 1 + luminosityFactor;
-                    red *= luminosityFactor;
-                    green *= luminosityFactor;
-                    blue *= luminosityFactor;
-                }
-                else if (luminosityFactor >= 0)
-                {
-                    red = (255 - red) * luminosityFactor + red;
-                    green = (255 - green) * luminosityFactor + green;
-                    blue = (255 - blue) * luminosityFactor + blue;
-                }
-
-                return new Color(color.A, (byte)red, (byte)green, (byte)blue);
-            }
         }
     }
 }

src/Avalonia.Base/Collections/AvaloniaDictionaryExtensions.cs

@@ -35,7 +35,7 @@ namespace Avalonia.Collections
         /// Indicates if a weak subscription should be used to track changes to the collection.
         /// </param>
         /// <returns>A disposable used to terminate the subscription.</returns>
-        internal static IDisposable ForEachItem<TKey, TValue>(
+        public static IDisposable ForEachItem<TKey, TValue>(
             this IAvaloniaReadOnlyDictionary<TKey, TValue> collection,
             Action<TKey, TValue> added,
             Action<TKey, TValue> removed,

src/Avalonia.Themes.Fluent/Accents/AccentColors.xaml

@@ -1,12 +0,0 @@
-<ResourceDictionary xmlns="https://github.com/avaloniaui"
-                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
-    <!-- Accent Colours -->
-    <!-- TODO pull accents from system... algorithm to generate shades -->
-    <Color x:Key="SystemAccentColor">#FF0078D7</Color>
-    <Color x:Key="SystemAccentColorDark1">#FF005A9E</Color>
-    <Color x:Key="SystemAccentColorDark2">#FF004275</Color>
-    <Color x:Key="SystemAccentColorDark3">#FF002642</Color>
-    <Color x:Key="SystemAccentColorLight1">#FF429CE3</Color>
-    <Color x:Key="SystemAccentColorLight2">#FF76B9ED</Color>
-    <Color x:Key="SystemAccentColorLight3">#FFA6D8FF</Color>
-</ResourceDictionary>

src/Avalonia.Themes.Fluent/Accents/BaseColorsPalette.xaml

@@ -0,0 +1,69 @@
+<ResourceDictionary xmlns="https://github.com/avaloniaui"
+                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+  <!-- https://docs.microsoft.com/en-us/previous-versions/windows/apps/dn518235(v=win.10)?redirectedfrom=MSDN -->
+  <ResourceDictionary.ThemeDictionaries>
+    <ResourceDictionary x:Key="Default">
+      <Color x:Key="SystemAltHighColor">#FFFFFFFF</Color>
+      <Color x:Key="SystemAltLowColor">#33FFFFFF</Color>
+      <Color x:Key="SystemAltMediumColor">#99FFFFFF</Color>
+      <Color x:Key="SystemAltMediumHighColor">#CCFFFFFF</Color>
+      <Color x:Key="SystemAltMediumLowColor">#66FFFFFF</Color>
+      <Color x:Key="SystemBaseHighColor">#FF000000</Color>
+      <Color x:Key="SystemBaseLowColor">#33000000</Color>
+      <Color x:Key="SystemBaseMediumColor">#99000000</Color>
+      <Color x:Key="SystemBaseMediumHighColor">#CC000000</Color>
+      <Color x:Key="SystemBaseMediumLowColor">#66000000</Color>
+      <Color x:Key="SystemChromeAltLowColor">#FF171717</Color>
+      <Color x:Key="SystemChromeBlackHighColor">#FF000000</Color>
+      <Color x:Key="SystemChromeBlackLowColor">#33000000</Color>
+      <Color x:Key="SystemChromeBlackMediumLowColor">#66000000</Color>
+      <Color x:Key="SystemChromeBlackMediumColor">#CC000000</Color>
+      <Color x:Key="SystemChromeDisabledHighColor">#FFCCCCCC</Color>
+      <Color x:Key="SystemChromeDisabledLowColor">#FF7A7A7A</Color>
+      <Color x:Key="SystemChromeHighColor">#FFCCCCCC</Color>
+      <Color x:Key="SystemChromeLowColor">#FFF2F2F2</Color>
+      <Color x:Key="SystemChromeMediumColor">#FFE6E6E6</Color>
+      <Color x:Key="SystemChromeMediumLowColor">#FFF2F2F2</Color>
+      <Color x:Key="SystemChromeWhiteColor">#FFFFFFFF</Color>
+      <Color x:Key="SystemChromeGrayColor">#FF767676</Color>
+      <Color x:Key="SystemListLowColor">#19000000</Color>
+      <Color x:Key="SystemListMediumColor">#33000000</Color>
+      <Color x:Key="SystemErrorTextColor">#C50500</Color>
+      <Color x:Key="SystemRegionColor">#FFFFFFFF</Color>
+      <Color x:Key="SystemRevealListLowColor">#17000000</Color>
+      <Color x:Key="SystemRevealListMediumColor">#2E000000</Color>
+    </ResourceDictionary>
+    <ResourceDictionary x:Key="Dark">
+      <Color x:Key="SystemAltHighColor">#FF000000</Color>
+      <Color x:Key="SystemAltLowColor">#33000000</Color>
+      <Color x:Key="SystemAltMediumColor">#99000000</Color>
+      <Color x:Key="SystemAltMediumHighColor">#CC000000</Color>
+      <Color x:Key="SystemAltMediumLowColor">#66000000</Color>
+      <Color x:Key="SystemBaseHighColor">#FFFFFFFF</Color>
+      <Color x:Key="SystemBaseLowColor">#33FFFFFF</Color>
+      <Color x:Key="SystemBaseMediumColor">#99FFFFFF</Color>
+      <Color x:Key="SystemBaseMediumHighColor">#CCFFFFFF</Color>
+      <Color x:Key="SystemBaseMediumLowColor">#66FFFFFF</Color>
+      <Color x:Key="SystemChromeAltLowColor">#FFF2F2F2</Color>
+      <Color x:Key="SystemChromeBlackHighColor">#FF000000</Color>
+      <Color x:Key="SystemChromeBlackLowColor">#33000000</Color>
+      <Color x:Key="SystemChromeBlackMediumLowColor">#66000000</Color>
+      <Color x:Key="SystemChromeBlackMediumColor">#CC000000</Color>
+      <Color x:Key="SystemChromeDisabledHighColor">#FF333333</Color>
+      <Color x:Key="SystemChromeDisabledLowColor">#FF858585</Color>
+      <Color x:Key="SystemChromeHighColor">#FF767676</Color>
+      <Color x:Key="SystemChromeLowColor">#FF171717</Color>
+      <Color x:Key="SystemChromeMediumColor">#FF1F1F1F</Color>
+      <Color x:Key="SystemChromeMediumLowColor">#FF2B2B2B</Color>
+      <Color x:Key="SystemChromeWhiteColor">#FFFFFFFF</Color>
+      <Color x:Key="SystemChromeGrayColor">#FF767676</Color>
+      <Color x:Key="SystemListLowColor">#19FFFFFF</Color>
+      <Color x:Key="SystemListMediumColor">#33FFFFFF</Color>
+      <Color x:Key="SystemErrorTextColor">#FFF000</Color>
+      <Color x:Key="SystemRegionColor">#FF000000</Color>
+      <Color x:Key="SystemRevealListLowColor">#18FFFFFF</Color>
+      <Color x:Key="SystemRevealListMediumColor">#30FFFFFF</Color>
+    </ResourceDictionary>
+  </ResourceDictionary.ThemeDictionaries>
+
+</ResourceDictionary>

src/Avalonia.Themes.Fluent/Accents/Base.xaml → src/Avalonia.Themes.Fluent/Accents/BaseResources.xaml

@@ -2,7 +2,6 @@
                     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                     xmlns:sys="using:System"
                     xmlns:converters="using:Avalonia.Controls.Converters">
-  <!-- https://docs.microsoft.com/en-us/previous-versions/windows/apps/dn518235(v=win.10)?redirectedfrom=MSDN -->
   <FontFamily x:Key="ContentControlThemeFontFamily">fonts:Inter#Inter, $Default</FontFamily>
   <sys:Double x:Key="ControlContentThemeFontSize">14</sys:Double>
 
@@ -28,39 +27,33 @@
   <converters:CornerRadiusFilterConverter x:Key="BottomCornerRadiusFilterConverter" Filter="BottomLeft, BottomRight" />
   <converters:CornerRadiusFilterConverter x:Key="LeftCornerRadiusFilterConverter" Filter="TopLeft, BottomLeft" />
 
-  <ResourceDictionary.ThemeDictionaries>
-    <ResourceDictionary x:Key="Default">
-      <!-- System Control Colors -->
-      <Color x:Key="SystemAltHighColor">#FFFFFFFF</Color>
-      <Color x:Key="SystemAltLowColor">#33FFFFFF</Color>
-      <Color x:Key="SystemAltMediumColor">#99FFFFFF</Color>
-      <Color x:Key="SystemAltMediumHighColor">#CCFFFFFF</Color>
-      <Color x:Key="SystemAltMediumLowColor">#66FFFFFF</Color>
-      <Color x:Key="SystemBaseHighColor">#FF000000</Color>
-      <Color x:Key="SystemBaseLowColor">#33000000</Color>
-      <Color x:Key="SystemBaseMediumColor">#99000000</Color>
-      <Color x:Key="SystemBaseMediumHighColor">#CC000000</Color>
-      <Color x:Key="SystemBaseMediumLowColor">#66000000</Color>
-      <Color x:Key="SystemChromeAltLowColor">#FF171717</Color>
-      <Color x:Key="SystemChromeBlackHighColor">#FF000000</Color>
-      <Color x:Key="SystemChromeBlackLowColor">#33000000</Color>
-      <Color x:Key="SystemChromeBlackMediumLowColor">#66000000</Color>
-      <Color x:Key="SystemChromeBlackMediumColor">#CC000000</Color>
-      <Color x:Key="SystemChromeDisabledHighColor">#FFCCCCCC</Color>
-      <Color x:Key="SystemChromeDisabledLowColor">#FF7A7A7A</Color>
-      <Color x:Key="SystemChromeHighColor">#FFCCCCCC</Color>
-      <Color x:Key="SystemChromeLowColor">#FFF2F2F2</Color>
-      <Color x:Key="SystemChromeMediumColor">#FFE6E6E6</Color>
-      <Color x:Key="SystemChromeMediumLowColor">#FFF2F2F2</Color>
-      <Color x:Key="SystemChromeWhiteColor">#FFFFFFFF</Color>
-      <Color x:Key="SystemChromeGrayColor">#FF767676</Color>
-      <Color x:Key="SystemListLowColor">#19000000</Color>
-      <Color x:Key="SystemListMediumColor">#33000000</Color>
-      <Color x:Key="SystemErrorTextColor">#C50500</Color>
+  <x:Double x:Key="AutoCompleteListMaxHeight">374</x:Double>
+  <Thickness x:Key="AutoCompleteListMargin">0,2,0,2</Thickness>
+  <Thickness x:Key="AutoCompleteListBorderThemeThickness">1</Thickness>
+  <Thickness x:Key="AutoCompleteListPadding">-1,0,-1,0</Thickness>
+  <x:Double x:Key="TextControlThemeMinHeight">32</x:Double>
+  <x:Double x:Key="TextControlThemeMinWidth">64</x:Double>
+  <x:Double x:Key="FlyoutThemeMaxWidth">456</x:Double>
+  <Thickness x:Key="DateTimeFlyoutButtonBorderThickness">0</Thickness>
+  <Thickness x:Key="DateTimeFlyoutBorderThickness">1</Thickness>
+  <Thickness x:Key="DateTimeFlyoutBorderPadding">0</Thickness>
+
+  <Thickness x:Key="FlyoutContentThemePadding">12,11,12,12</Thickness>
+  <x:Double x:Key="FlyoutThemeMinWidth">96</x:Double>
+  <x:Double x:Key="FlyoutThemeMinHeight">40</x:Double>
+  <x:Double x:Key="FlyoutThemeMaxHeight">758</x:Double>
 
-      <Color x:Key="SystemRevealListLowColor">#17000000</Color>
-      <Color x:Key="SystemRevealListMediumColor">#2E000000</Color>
+  <!-- Moved from FlyoutPresenter.xaml -->
+  <Thickness x:Key="FlyoutBorderThemePadding">0</Thickness>
 
+  <!-- Moved from MenuItem.xaml -->
+  <Thickness x:Key="MenuFlyoutScrollerMargin">0,4,0,4</Thickness>
+
+  <!-- Moved from Menu.xaml -->
+  <Thickness x:Key="MenuBarItemPadding">12,0,12,0</Thickness>
+  
+  <ResourceDictionary.ThemeDictionaries>
+    <ResourceDictionary x:Key="Default">
       <SolidColorBrush x:Key="SystemControlBackgroundAccentBrush" Color="{DynamicResource SystemAccentColor}" />
       <SolidColorBrush x:Key="SystemControlBackgroundAltHighBrush" Color="{StaticResource SystemAltHighColor}" />
       <SolidColorBrush x:Key="SystemControlBackgroundAltMediumHighBrush"
@@ -211,82 +204,17 @@
                        Color="{StaticResource SystemChromeWhiteColor}" />
       <SolidColorBrush x:Key="SystemControlHighlightAltTransparentRevealBorderBrush" Color="Transparent" />
       <SolidColorBrush x:Key="SystemControlBackgroundTransparentRevealBorderBrush" Color="Transparent" />
-      <!-- TODO implement AcrylicBrush -->
-      <!--<AcrylicBrush x:Key="SystemControlTransientBackgroundBrush" BackgroundSource="HostBackdrop" TintColor="{StaticResource SystemChromeAltHighColor}" TintOpacity="0.8" FallbackColor="{StaticResource SystemChromeMediumLowColor}" />-->
       <SolidColorBrush x:Key="SystemControlTransientBackgroundBrush"
                        Color="{StaticResource SystemChromeMediumLowColor}" />
       <StaticResource x:Key="SystemControlDescriptionTextForegroundBrush"
                       ResourceKey="SystemControlPageTextBaseMediumBrush" />
 
-      <!--<AcrylicBrush x:Key="SystemControlAcrylicWindowBrush" BackgroundSource="HostBackdrop" TintColor="{ThemeResource SystemChromeAltHighColor}" TintOpacity="0.8" FallbackColor="{ThemeResource SystemChromeMediumColor}" />-->
-      <!--<RevealBackgroundBrush x:Key="SystemControlTransparentRevealBackgroundBrush" TargetTheme="Dark" Color="Transparent" FallbackColor="Transparent" />-->
       <SolidColorBrush x:Key="SystemControlTransparentRevealBackgroundBrush" Color="Transparent" />
-      <!--<RevealBorderBrush x:Key="SystemControlTransparentRevealBorderBrush" TargetTheme="Dark" Color="Transparent" FallbackColor="Transparent" />-->
       <SolidColorBrush x:Key="SystemControlTransparentRevealBorderBrush" Color="Transparent" />
 
-
-      <!--<RevealBackgroundBrush x:Key="SystemControlHighlightListLowRevealBackgroundBrush" TargetTheme="Light" Color="{ThemeResource SystemRevealListMediumColor}" FallbackColor="{ StaticResource SystemListMediumColor}" />-->
-      <Color x:Key="RegionColor">#FFFFFFFF</Color>
-      <SolidColorBrush x:Key="RegionBrush" Color="{StaticResource RegionColor}" />
-
-
-      <x:Double x:Key="AutoCompleteListMaxHeight">374</x:Double>
-      <Thickness x:Key="AutoCompleteListMargin">0,2,0,2</Thickness>
-      <Thickness x:Key="AutoCompleteListBorderThemeThickness">1</Thickness>
-      <Thickness x:Key="AutoCompleteListPadding">-1,0,-1,0</Thickness>
-      <x:Double x:Key="TextControlThemeMinHeight">32</x:Double>
-      <x:Double x:Key="TextControlThemeMinWidth">64</x:Double>
-      <x:Double x:Key="FlyoutThemeMaxWidth">456</x:Double>
-      <Thickness x:Key="DateTimeFlyoutButtonBorderThickness">0</Thickness>
-      <Thickness x:Key="DateTimeFlyoutBorderThickness">1</Thickness>
-      <Thickness x:Key="DateTimeFlyoutBorderPadding">0</Thickness>
-
-      <Thickness x:Key="FlyoutContentThemePadding">12,11,12,12</Thickness>
-      <x:Double x:Key="FlyoutThemeMinWidth">96</x:Double>
-      <x:Double x:Key="FlyoutThemeMinHeight">40</x:Double>
-      <x:Double x:Key="FlyoutThemeMaxHeight">758</x:Double>
-
-      <!-- Moved from FlyoutPresenter.xaml -->
-      <Thickness x:Key="FlyoutBorderThemePadding">0</Thickness>
-
-      <!-- Moved from MenuItem.xaml -->
-      <Thickness x:Key="MenuFlyoutScrollerMargin">0,4,0,4</Thickness>
-
-      <!-- Moved from Menu.xaml -->
-      <Thickness x:Key="MenuBarItemPadding">12,0,12,0</Thickness>
+      <SolidColorBrush x:Key="SystemRegionBrush" Color="{StaticResource SystemRegionColor}" />
     </ResourceDictionary>
     <ResourceDictionary x:Key="Dark">
-      <!-- System Control Colors -->
-      <Color x:Key="SystemAltHighColor">#FF000000</Color>
-      <Color x:Key="SystemAltLowColor">#33000000</Color>
-      <Color x:Key="SystemAltMediumColor">#99000000</Color>
-      <Color x:Key="SystemAltMediumHighColor">#CC000000</Color>
-      <Color x:Key="SystemAltMediumLowColor">#66000000</Color>
-      <Color x:Key="SystemBaseHighColor">#FFFFFFFF</Color>
-      <Color x:Key="SystemBaseLowColor">#33FFFFFF</Color>
-      <Color x:Key="SystemBaseMediumColor">#99FFFFFF</Color>
-      <Color x:Key="SystemBaseMediumHighColor">#CCFFFFFF</Color>
-      <Color x:Key="SystemBaseMediumLowColor">#66FFFFFF</Color>
-      <Color x:Key="SystemChromeAltLowColor">#FFF2F2F2</Color>
-      <Color x:Key="SystemChromeBlackHighColor">#FF000000</Color>
-      <Color x:Key="SystemChromeBlackLowColor">#33000000</Color>
-      <Color x:Key="SystemChromeBlackMediumLowColor">#66000000</Color>
-      <Color x:Key="SystemChromeBlackMediumColor">#CC000000</Color>
-      <Color x:Key="SystemChromeDisabledHighColor">#FF333333</Color>
-      <Color x:Key="SystemChromeDisabledLowColor">#FF858585</Color>
-      <Color x:Key="SystemChromeHighColor">#FF767676</Color>
-      <Color x:Key="SystemChromeLowColor">#FF171717</Color>
-      <Color x:Key="SystemChromeMediumColor">#FF1F1F1F</Color>
-      <Color x:Key="SystemChromeMediumLowColor">#FF2B2B2B</Color>
-      <Color x:Key="SystemChromeWhiteColor">#FFFFFFFF</Color>
-      <Color x:Key="SystemChromeGrayColor">#FF767676</Color>
-      <Color x:Key="SystemListLowColor">#19FFFFFF</Color>
-      <Color x:Key="SystemListMediumColor">#33FFFFFF</Color>
-      <Color x:Key="SystemErrorTextColor">#FFF000</Color>
-
-      <Color x:Key="SystemRevealListLowColor">#18FFFFFF</Color>
-      <Color x:Key="SystemRevealListMediumColor">#30FFFFFF</Color>
-
       <SolidColorBrush x:Key="SystemControlBackgroundAccentBrush" Color="{DynamicResource SystemAccentColor}" />
       <SolidColorBrush x:Key="SystemControlBackgroundAltHighBrush" Color="{StaticResource SystemAltHighColor}" />
       <SolidColorBrush x:Key="SystemControlBackgroundAltMediumHighBrush"
@@ -437,46 +365,14 @@
                        Color="{StaticResource SystemChromeWhiteColor}" />
       <SolidColorBrush x:Key="SystemControlHighlightAltTransparentRevealBorderBrush" Color="Transparent" />
       <SolidColorBrush x:Key="SystemControlBackgroundTransparentRevealBorderBrush" Color="Transparent" />
-      <!-- TODO implement AcrylicBrush -->
-      <!--<AcrylicBrush x:Key="SystemControlTransientBackgroundBrush" BackgroundSource="HostBackdrop" TintColor="{StaticResource SystemChromeAltHighColor}" TintOpacity="0.8" FallbackColor="{StaticResource SystemChromeMediumLowColor}" />-->
       <SolidColorBrush x:Key="SystemControlTransientBackgroundBrush"
                        Color="{StaticResource SystemChromeMediumLowColor}" />
       <StaticResource x:Key="SystemControlDescriptionTextForegroundBrush"
                       ResourceKey="SystemControlPageTextBaseMediumBrush" />
-
-      <!--<AcrylicBrush x:Key="SystemControlAcrylicWindowBrush" BackgroundSource="HostBackdrop" TintColor="{ThemeResource SystemChromeAltHighColor}" TintOpacity="0.8" FallbackColor="{ThemeResource SystemChromeMediumColor}" />-->
-      <!--<RevealBackgroundBrush x:Key="SystemControlTransparentRevealBackgroundBrush" TargetTheme="Dark" Color="Transparent" FallbackColor="Transparent" />-->
       <SolidColorBrush x:Key="SystemControlTransparentRevealBackgroundBrush" Color="Transparent" />
-      <!--<RevealBorderBrush x:Key="SystemControlTransparentRevealBorderBrush" TargetTheme="Dark" Color="Transparent" FallbackColor="Transparent" />-->
       <SolidColorBrush x:Key="SystemControlTransparentRevealBorderBrush" Color="Transparent" />
 
-      <Color x:Key="RegionColor">#FF000000</Color>
-      <SolidColorBrush x:Key="RegionBrush" Color="{StaticResource RegionColor}" />
-
-      <x:Double x:Key="AutoCompleteListMaxHeight">374</x:Double>
-      <Thickness x:Key="AutoCompleteListMargin">0,2,0,2</Thickness>
-      <Thickness x:Key="AutoCompleteListBorderThemeThickness">1</Thickness>
-      <Thickness x:Key="AutoCompleteListPadding">-1,0,-1,0</Thickness>
-      <x:Double x:Key="TextControlThemeMinHeight">32</x:Double>
-      <x:Double x:Key="TextControlThemeMinWidth">64</x:Double>
-      <x:Double x:Key="FlyoutThemeMaxWidth">456</x:Double>
-      <Thickness x:Key="DateTimeFlyoutButtonBorderThickness">0</Thickness>
-      <Thickness x:Key="DateTimeFlyoutBorderThickness">1</Thickness>
-      <Thickness x:Key="DateTimeFlyoutBorderPadding">0</Thickness>
-
-      <Thickness x:Key="FlyoutContentThemePadding">12,11,12,12</Thickness>
-      <x:Double x:Key="FlyoutThemeMinWidth">96</x:Double>
-      <x:Double x:Key="FlyoutThemeMinHeight">40</x:Double>
-      <x:Double x:Key="FlyoutThemeMaxHeight">758</x:Double>
-
-      <!-- Moved from FlyoutPresenter.xaml -->
-      <Thickness x:Key="FlyoutBorderThemePadding">0</Thickness>
-
-      <!-- Moved from MenuItem.xaml -->
-      <Thickness x:Key="MenuFlyoutScrollerMargin">0,4,0,4</Thickness>
-
-      <!-- Moved from Menu.xaml -->
-      <Thickness x:Key="MenuBarItemPadding">12,0,12,0</Thickness>
+      <SolidColorBrush x:Key="SystemRegionBrush" Color="{StaticResource SystemRegionColor}" />
     </ResourceDictionary>
   </ResourceDictionary.ThemeDictionaries>
 </ResourceDictionary>

src/Avalonia.Themes.Fluent/Accents/FluentControlResources.xaml

@@ -4,8 +4,8 @@
     <ResourceDictionary x:Key="Default">
       <!-- Resources for Button.xaml -->
       <StaticResource x:Key="AccentButtonBackground" ResourceKey="SystemControlBackgroundAccentBrush" />
-      <StaticResource x:Key="AccentButtonBackgroundPointerOver" ResourceKey="SystemAccentColorLight1" />
-      <StaticResource x:Key="AccentButtonBackgroundPressed" ResourceKey="SystemAccentColorDark1" />
+      <SolidColorBrush x:Key="AccentButtonBackgroundPointerOver" Color="{DynamicResource SystemAccentColorLight1}" />
+      <SolidColorBrush x:Key="AccentButtonBackgroundPressed" Color="{DynamicResource SystemAccentColorDark1}" />
       <StaticResource x:Key="AccentButtonBackgroundDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
       <StaticResource x:Key="AccentButtonForeground" ResourceKey="SystemControlBackgroundChromeWhiteBrush" />
       <StaticResource x:Key="AccentButtonForegroundPointerOver" ResourceKey="SystemControlBackgroundChromeWhiteBrush" />
@@ -52,7 +52,8 @@
       <StaticResource x:Key="ToggleButtonBackgroundPressed" ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
       <StaticResource x:Key="ToggleButtonBackgroundDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
       <StaticResource x:Key="ToggleButtonBackgroundChecked" ResourceKey="SystemControlHighlightAccentBrush" />
-      <StaticResource x:Key="ToggleButtonBackgroundCheckedPointerOver" ResourceKey="SystemAccentColorLight1" />
+      <SolidColorBrush x:Key="ToggleButtonBackgroundCheckedPointerOver"
+                       Color="{DynamicResource SystemAccentColorLight1}" />
       <StaticResource x:Key="ToggleButtonBackgroundCheckedPressed"
                       ResourceKey="SystemControlHighlightBaseMediumLowBrush" />
       <StaticResource x:Key="ToggleButtonBackgroundCheckedDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
@@ -291,15 +292,17 @@
                       ResourceKey="SystemControlHighlightBaseHighBrush" />
       <StaticResource x:Key="CheckBoxCheckBackgroundStrokeUncheckedDisabled"
                       ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
-      <StaticResource x:Key="CheckBoxCheckBackgroundStrokeCheckedPointerOver" ResourceKey="SystemAccentColorLight1" />
+      <SolidColorBrush x:Key="CheckBoxCheckBackgroundStrokeCheckedPointerOver"
+                       Color="{DynamicResource SystemAccentColorLight1}" />
       <StaticResource x:Key="CheckBoxCheckBackgroundStrokeCheckedPressed"
                       ResourceKey="SystemControlHighlightTransparentBrush" />
       <StaticResource x:Key="CheckBoxCheckBackgroundStrokeCheckedDisabled" ResourceKey="SystemControlTransparentBrush" />
       <StaticResource x:Key="CheckBoxCheckBackgroundStrokeIndeterminate"
                       ResourceKey="SystemControlHighlightAccentBrush" />
-      <StaticResource x:Key="CheckBoxCheckBackgroundStrokeIndeterminatePointerOver"
-                      ResourceKey="SystemAccentColorLight1" />
-      <StaticResource x:Key="CheckBoxCheckBackgroundStrokeIndeterminatePressed" ResourceKey="SystemAccentColorDark1" />
+      <SolidColorBrush x:Key="CheckBoxCheckBackgroundStrokeIndeterminatePointerOver"
+                       Color="{DynamicResource SystemAccentColorLight1}" />
+      <SolidColorBrush x:Key="CheckBoxCheckBackgroundStrokeIndeterminatePressed"
+                       Color="{DynamicResource SystemAccentColorDark1}" />
       <StaticResource x:Key="CheckBoxCheckBackgroundStrokeIndeterminateDisabled"
                       ResourceKey="SystemControlTransparentBrush" />
       <StaticResource x:Key="CheckBoxCheckBackgroundFillUnchecked" ResourceKey="SystemControlTransparentBrush" />
@@ -309,13 +312,17 @@
                       ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
       <StaticResource x:Key="CheckBoxCheckBackgroundFillUncheckedDisabled" ResourceKey="SystemControlTransparentBrush" />
       <StaticResource x:Key="CheckBoxCheckBackgroundFillChecked" ResourceKey="SystemControlHighlightAccentBrush" />
-      <StaticResource x:Key="CheckBoxCheckBackgroundFillCheckedPointerOver" ResourceKey="SystemAccentColorLight1" />
-      <StaticResource x:Key="CheckBoxCheckBackgroundFillCheckedPressed" ResourceKey="SystemAccentColorDark1" />
+      <SolidColorBrush x:Key="CheckBoxCheckBackgroundFillCheckedPointerOver"
+                       Color="{DynamicResource SystemAccentColorLight1}" />
+      <SolidColorBrush x:Key="CheckBoxCheckBackgroundFillCheckedPressed"
+                       Color="{DynamicResource SystemAccentColorDark1}" />
       <StaticResource x:Key="CheckBoxCheckBackgroundFillCheckedDisabled"
                       ResourceKey="SystemControlBackgroundBaseLowBrush" />
       <StaticResource x:Key="CheckBoxCheckBackgroundFillIndeterminate" ResourceKey="SystemControlHighlightAccentBrush" />
-      <StaticResource x:Key="CheckBoxCheckBackgroundFillIndeterminatePointerOver" ResourceKey="SystemAccentColorLight1" />
-      <StaticResource x:Key="CheckBoxCheckBackgroundFillIndeterminatePressed" ResourceKey="SystemAccentColorDark1" />
+      <SolidColorBrush x:Key="CheckBoxCheckBackgroundFillIndeterminatePointerOver"
+                       Color="{DynamicResource SystemAccentColorLight1}" />
+      <SolidColorBrush x:Key="CheckBoxCheckBackgroundFillIndeterminatePressed"
+                       Color="{DynamicResource SystemAccentColorDark1}" />
       <StaticResource x:Key="CheckBoxCheckBackgroundFillIndeterminateDisabled"
                       ResourceKey="SystemControlBackgroundBaseLowBrush" />
       <StaticResource x:Key="CheckBoxCheckGlyphForegroundUnchecked"
@@ -442,13 +449,17 @@
                       ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
       <StaticResource x:Key="RadioButtonOuterEllipseFillDisabled" ResourceKey="SystemControlTransparentBrush" />
       <StaticResource x:Key="RadioButtonOuterEllipseCheckedStroke" ResourceKey="SystemControlHighlightAccentBrush" />
-      <StaticResource x:Key="RadioButtonOuterEllipseCheckedStrokePointerOver" ResourceKey="SystemAccentColorLight1" />
-      <StaticResource x:Key="RadioButtonOuterEllipseCheckedStrokePressed" ResourceKey="SystemAccentColorDark1" />
+      <SolidColorBrush x:Key="RadioButtonOuterEllipseCheckedStrokePointerOver"
+                       Color="{DynamicResource SystemAccentColorLight1}" />
+      <SolidColorBrush x:Key="RadioButtonOuterEllipseCheckedStrokePressed"
+                       Color="{DynamicResource SystemAccentColorDark1}" />
       <StaticResource x:Key="RadioButtonOuterEllipseCheckedStrokeDisabled"
                       ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
       <StaticResource x:Key="RadioButtonOuterEllipseCheckedFill" ResourceKey="SystemControlHighlightAccentBrush" />
-      <StaticResource x:Key="RadioButtonOuterEllipseCheckedFillPointerOver" ResourceKey="SystemAccentColorLight1" />
-      <StaticResource x:Key="RadioButtonOuterEllipseCheckedFillPressed" ResourceKey="SystemAccentColorDark1" />
+      <SolidColorBrush x:Key="RadioButtonOuterEllipseCheckedFillPointerOver"
+                       Color="{DynamicResource SystemAccentColorLight1}" />
+      <SolidColorBrush x:Key="RadioButtonOuterEllipseCheckedFillPressed"
+                       Color="{DynamicResource SystemAccentColorDark1}" />
       <StaticResource x:Key="RadioButtonOuterEllipseCheckedFillDisabled"
                       ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
       <StaticResource x:Key="RadioButtonCheckGlyphFill" ResourceKey="SystemControlForegroundChromeWhiteBrush" />
@@ -470,8 +481,8 @@
       <StaticResource x:Key="SliderContainerBackgroundPressed" ResourceKey="SystemControlTransparentBrush" />
       <StaticResource x:Key="SliderContainerBackgroundDisabled" ResourceKey="SystemControlTransparentBrush" />
       <StaticResource x:Key="SliderThumbBackground" ResourceKey="SystemControlForegroundAccentBrush" />
-      <StaticResource x:Key="SliderThumbBackgroundPointerOver" ResourceKey="SystemAccentColorLight1" />
-      <StaticResource x:Key="SliderThumbBackgroundPressed" ResourceKey="SystemAccentColorDark1" />
+      <SolidColorBrush x:Key="SliderThumbBackgroundPointerOver" Color="{DynamicResource SystemAccentColorLight1}" />
+      <SolidColorBrush x:Key="SliderThumbBackgroundPressed" Color="{DynamicResource SystemAccentColorDark1}" />
       <StaticResource x:Key="SliderThumbBackgroundDisabled" ResourceKey="SystemControlDisabledChromeDisabledHighBrush" />
       <StaticResource x:Key="SliderTrackFill" ResourceKey="SystemControlForegroundBaseMediumLowBrush" />
       <StaticResource x:Key="SliderTrackFillPointerOver" ResourceKey="SystemControlForegroundBaseMediumBrush" />
@@ -502,8 +513,8 @@
       <StaticResource x:Key="ToggleSwitchStrokeOffPressed" ResourceKey="SystemControlForegroundBaseHighBrush" />
       <StaticResource x:Key="ToggleSwitchStrokeOffDisabled" ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
       <StaticResource x:Key="ToggleSwitchFillOn" ResourceKey="SystemControlHighlightAccentBrush" />
-      <StaticResource x:Key="ToggleSwitchFillOnPointerOver" ResourceKey="SystemAccentColorLight1" />
-      <StaticResource x:Key="ToggleSwitchFillOnPressed" ResourceKey="SystemAccentColorDark1" />
+      <SolidColorBrush x:Key="ToggleSwitchFillOnPointerOver" Color="{DynamicResource SystemAccentColorLight1}" />
+      <SolidColorBrush x:Key="ToggleSwitchFillOnPressed" Color="{DynamicResource SystemAccentColorDark1}" />
       <StaticResource x:Key="ToggleSwitchFillOnDisabled" ResourceKey="SystemControlDisabledBaseLowBrush" />
       <StaticResource x:Key="ToggleSwitchStrokeOn" ResourceKey="SystemControlHighlightBaseHighBrush" />
       <StaticResource x:Key="ToggleSwitchStrokeOnPointerOver" ResourceKey="SystemControlHighlightListAccentHighBrush" />
@@ -701,8 +712,9 @@
       <StaticResource x:Key="SplitButtonBackgroundPressed" ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
       <StaticResource x:Key="SplitButtonBackgroundDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
       <StaticResource x:Key="SplitButtonBackgroundChecked" ResourceKey="SystemControlHighlightAccentBrush" />
-      <StaticResource x:Key="SplitButtonBackgroundCheckedPointerOver" ResourceKey="SystemAccentColorLight1" />
-      <StaticResource x:Key="SplitButtonBackgroundCheckedPressed" ResourceKey="SystemAccentColorDark1" />
+      <SolidColorBrush x:Key="SplitButtonBackgroundCheckedPointerOver"
+                       Color="{DynamicResource SystemAccentColorLight1}" />
+      <SolidColorBrush x:Key="SplitButtonBackgroundCheckedPressed" Color="{DynamicResource SystemAccentColorDark1}" />
       <StaticResource x:Key="SplitButtonBackgroundCheckedDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
       <StaticResource x:Key="SplitButtonForeground" ResourceKey="SystemControlForegroundBaseHighBrush" />
       <StaticResource x:Key="SplitButtonForegroundPointerOver" ResourceKey="SystemControlHighlightBaseHighBrush" />
@@ -775,8 +787,8 @@
     <ResourceDictionary x:Key="Dark">
       <!-- Resources for Button.xaml -->
       <StaticResource x:Key="AccentButtonBackground" ResourceKey="SystemControlBackgroundAccentBrush" />
-      <StaticResource x:Key="AccentButtonBackgroundPointerOver" ResourceKey="SystemAccentColorLight1" />
-      <StaticResource x:Key="AccentButtonBackgroundPressed" ResourceKey="SystemAccentColorDark1" />
+      <SolidColorBrush x:Key="AccentButtonBackgroundPointerOver" Color="{DynamicResource SystemAccentColorLight1}" />
+      <SolidColorBrush x:Key="AccentButtonBackgroundPressed" Color="{DynamicResource SystemAccentColorDark1}" />
       <StaticResource x:Key="AccentButtonBackgroundDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
       <StaticResource x:Key="AccentButtonForeground" ResourceKey="SystemControlBackgroundChromeWhiteBrush" />
       <StaticResource x:Key="AccentButtonForegroundPointerOver" ResourceKey="SystemControlBackgroundChromeWhiteBrush" />
@@ -823,7 +835,8 @@
       <StaticResource x:Key="ToggleButtonBackgroundPressed" ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
       <StaticResource x:Key="ToggleButtonBackgroundDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
       <StaticResource x:Key="ToggleButtonBackgroundChecked" ResourceKey="SystemControlHighlightAccentBrush" />
-      <StaticResource x:Key="ToggleButtonBackgroundCheckedPointerOver" ResourceKey="SystemAccentColorDark1" />
+      <SolidColorBrush x:Key="ToggleButtonBackgroundCheckedPointerOver"
+                       Color="{DynamicResource SystemAccentColorDark1}" />
       <StaticResource x:Key="ToggleButtonBackgroundCheckedPressed"
                       ResourceKey="SystemControlHighlightBaseMediumLowBrush" />
       <StaticResource x:Key="ToggleButtonBackgroundCheckedDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
@@ -1065,14 +1078,17 @@
                       ResourceKey="SystemControlHighlightBaseHighBrush" />
       <StaticResource x:Key="CheckBoxCheckBackgroundStrokeUncheckedDisabled"
                       ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
-      <StaticResource x:Key="CheckBoxCheckBackgroundStrokeCheckedPointerOver" ResourceKey="SystemAccentColorDark1" />
-      <StaticResource x:Key="CheckBoxCheckBackgroundStrokeCheckedPressed" ResourceKey="SystemAccentColorLight1" />
+      <SolidColorBrush x:Key="CheckBoxCheckBackgroundStrokeCheckedPointerOver"
+                       Color="{DynamicResource SystemAccentColorDark1}" />
+      <SolidColorBrush x:Key="CheckBoxCheckBackgroundStrokeCheckedPressed"
+                       Color="{DynamicResource SystemAccentColorLight1}" />
       <StaticResource x:Key="CheckBoxCheckBackgroundStrokeCheckedDisabled" ResourceKey="SystemControlTransparentBrush" />
       <StaticResource x:Key="CheckBoxCheckBackgroundStrokeIndeterminate"
                       ResourceKey="SystemControlForegroundAccentBrush" />
-      <StaticResource x:Key="CheckBoxCheckBackgroundStrokeIndeterminatePointerOver"
-                      ResourceKey="SystemAccentColorLight1" />
-      <StaticResource x:Key="CheckBoxCheckBackgroundStrokeIndeterminatePressed" ResourceKey="SystemAccentColorDark1" />
+      <SolidColorBrush x:Key="CheckBoxCheckBackgroundStrokeIndeterminatePointerOver"
+                       Color="{DynamicResource SystemAccentColorLight1}" />
+      <SolidColorBrush x:Key="CheckBoxCheckBackgroundStrokeIndeterminatePressed"
+                       Color="{DynamicResource SystemAccentColorDark1}" />
       <StaticResource x:Key="CheckBoxCheckBackgroundStrokeIndeterminateDisabled"
                       ResourceKey="SystemControlTransparentBrush" />
       <StaticResource x:Key="CheckBoxCheckBackgroundFillUnchecked" ResourceKey="SystemControlTransparentBrush" />
@@ -1082,13 +1098,17 @@
                       ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
       <StaticResource x:Key="CheckBoxCheckBackgroundFillUncheckedDisabled" ResourceKey="SystemControlTransparentBrush" />
       <StaticResource x:Key="CheckBoxCheckBackgroundFillChecked" ResourceKey="SystemControlHighlightAccentBrush" />
-      <StaticResource x:Key="CheckBoxCheckBackgroundFillCheckedPointerOver" ResourceKey="SystemAccentColorLight1" />
-      <StaticResource x:Key="CheckBoxCheckBackgroundFillCheckedPressed" ResourceKey="SystemAccentColorDark1" />
+      <SolidColorBrush x:Key="CheckBoxCheckBackgroundFillCheckedPointerOver"
+                       Color="{DynamicResource SystemAccentColorLight1}" />
+      <SolidColorBrush x:Key="CheckBoxCheckBackgroundFillCheckedPressed"
+                       Color="{DynamicResource SystemAccentColorDark1}" />
       <StaticResource x:Key="CheckBoxCheckBackgroundFillCheckedDisabled"
                       ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
       <StaticResource x:Key="CheckBoxCheckBackgroundFillIndeterminate" ResourceKey="SystemControlHighlightAccentBrush" />
-      <StaticResource x:Key="CheckBoxCheckBackgroundFillIndeterminatePointerOver" ResourceKey="SystemAccentColorLight1" />
-      <StaticResource x:Key="CheckBoxCheckBackgroundFillIndeterminatePressed" ResourceKey="SystemAccentColorDark1" />
+      <SolidColorBrush x:Key="CheckBoxCheckBackgroundFillIndeterminatePointerOver"
+                       Color="{DynamicResource SystemAccentColorLight1}" />
+      <SolidColorBrush x:Key="CheckBoxCheckBackgroundFillIndeterminatePressed"
+                       Color="{DynamicResource SystemAccentColorDark1}" />
       <StaticResource x:Key="CheckBoxCheckBackgroundFillIndeterminateDisabled"
                       ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
       <StaticResource x:Key="CheckBoxCheckGlyphForegroundUnchecked"
@@ -1215,13 +1235,17 @@
                       ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
       <StaticResource x:Key="RadioButtonOuterEllipseFillDisabled" ResourceKey="SystemControlTransparentBrush" />
       <StaticResource x:Key="RadioButtonOuterEllipseCheckedStroke" ResourceKey="SystemControlHighlightAccentBrush" />
-      <StaticResource x:Key="RadioButtonOuterEllipseCheckedStrokePointerOver" ResourceKey="SystemAccentColorLight1" />
-      <StaticResource x:Key="RadioButtonOuterEllipseCheckedStrokePressed" ResourceKey="SystemAccentColorDark1" />
+      <SolidColorBrush x:Key="RadioButtonOuterEllipseCheckedStrokePointerOver"
+                       Color="{DynamicResource SystemAccentColorLight1}" />
+      <SolidColorBrush x:Key="RadioButtonOuterEllipseCheckedStrokePressed"
+                       Color="{DynamicResource SystemAccentColorDark1}" />
       <StaticResource x:Key="RadioButtonOuterEllipseCheckedStrokeDisabled"
                       ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
       <StaticResource x:Key="RadioButtonOuterEllipseCheckedFill" ResourceKey="SystemControlHighlightAccentBrush" />
-      <StaticResource x:Key="RadioButtonOuterEllipseCheckedFillPointerOver" ResourceKey="SystemAccentColorLight1" />
-      <StaticResource x:Key="RadioButtonOuterEllipseCheckedFillPressed" ResourceKey="SystemAccentColorDark1" />
+      <SolidColorBrush x:Key="RadioButtonOuterEllipseCheckedFillPointerOver"
+                       Color="{DynamicResource SystemAccentColorLight1}" />
+      <SolidColorBrush x:Key="RadioButtonOuterEllipseCheckedFillPressed"
+                       Color="{DynamicResource SystemAccentColorDark1}" />
       <StaticResource x:Key="RadioButtonOuterEllipseCheckedFillDisabled"
                       ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
       <StaticResource x:Key="RadioButtonCheckGlyphFill" ResourceKey="SystemControlForegroundChromeWhiteBrush" />
@@ -1243,8 +1267,8 @@
       <StaticResource x:Key="SliderContainerBackgroundPressed" ResourceKey="SystemControlTransparentBrush" />
       <StaticResource x:Key="SliderContainerBackgroundDisabled" ResourceKey="SystemControlTransparentBrush" />
       <StaticResource x:Key="SliderThumbBackground" ResourceKey="SystemControlForegroundAccentBrush" />
-      <StaticResource x:Key="SliderThumbBackgroundPointerOver" ResourceKey="SystemAccentColorLight1" />
-      <StaticResource x:Key="SliderThumbBackgroundPressed" ResourceKey="SystemAccentColorDark1" />
+      <SolidColorBrush x:Key="SliderThumbBackgroundPointerOver" Color="{DynamicResource SystemAccentColorLight1}" />
+      <SolidColorBrush x:Key="SliderThumbBackgroundPressed" Color="{DynamicResource SystemAccentColorDark1}" />
       <StaticResource x:Key="SliderThumbBackgroundDisabled" ResourceKey="SystemControlDisabledChromeDisabledHighBrush" />
       <StaticResource x:Key="SliderTrackFill" ResourceKey="SystemControlForegroundBaseMediumLowBrush" />
       <StaticResource x:Key="SliderTrackFillPointerOver" ResourceKey="SystemControlForegroundBaseMediumBrush" />
@@ -1275,12 +1299,12 @@
       <StaticResource x:Key="ToggleSwitchStrokeOffPressed" ResourceKey="SystemControlForegroundBaseHighBrush" />
       <StaticResource x:Key="ToggleSwitchStrokeOffDisabled" ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
       <StaticResource x:Key="ToggleSwitchFillOn" ResourceKey="SystemControlHighlightAccentBrush" />
-      <StaticResource x:Key="ToggleSwitchFillOnPointerOver" ResourceKey="SystemAccentColorLight1" />
-      <StaticResource x:Key="ToggleSwitchFillOnPressed" ResourceKey="SystemAccentColorDark1" />
+      <SolidColorBrush x:Key="ToggleSwitchFillOnPointerOver" Color="{DynamicResource SystemAccentColorLight1}" />
+      <SolidColorBrush x:Key="ToggleSwitchFillOnPressed" Color="{DynamicResource SystemAccentColorDark1}" />
       <StaticResource x:Key="ToggleSwitchFillOnDisabled" ResourceKey="SystemControlDisabledBaseLowBrush" />
       <StaticResource x:Key="ToggleSwitchStrokeOn" ResourceKey="SystemControlHighlightBaseHighBrush" />
-      <StaticResource x:Key="ToggleSwitchStrokeOnPointerOver" ResourceKey="SystemAccentColorLight1" />
-      <StaticResource x:Key="ToggleSwitchStrokeOnPressed" ResourceKey="SystemAccentColorDark1" />
+      <SolidColorBrush x:Key="ToggleSwitchStrokeOnPointerOver" Color="{DynamicResource SystemAccentColorLight1}" />
+      <SolidColorBrush x:Key="ToggleSwitchStrokeOnPressed" Color="{DynamicResource SystemAccentColorDark1}" />
       <StaticResource x:Key="ToggleSwitchStrokeOnDisabled" ResourceKey="SystemControlDisabledBaseMediumLowBrush" />
       <StaticResource x:Key="ToggleSwitchKnobFillOff" ResourceKey="SystemControlHighlightBaseHighBrush" />
       <StaticResource x:Key="ToggleSwitchKnobFillOffPointerOver" ResourceKey="SystemControlHighlightBaseHighBrush" />
@@ -1476,8 +1500,8 @@
       <StaticResource x:Key="SplitButtonBackgroundPressed" ResourceKey="SystemControlBackgroundBaseMediumLowBrush" />
       <StaticResource x:Key="SplitButtonBackgroundDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
       <StaticResource x:Key="SplitButtonBackgroundChecked" ResourceKey="SystemControlHighlightAccentBrush" />
-      <StaticResource x:Key="SplitButtonBackgroundCheckedPointerOver" ResourceKey="SystemAccentColorDark1" />
-      <StaticResource x:Key="SplitButtonBackgroundCheckedPressed" ResourceKey="SystemAccentColorLight1" />
+      <SolidColorBrush x:Key="SplitButtonBackgroundCheckedPointerOver" Color="{DynamicResource SystemAccentColorDark1}" />
+      <SolidColorBrush x:Key="SplitButtonBackgroundCheckedPressed" Color="{DynamicResource SystemAccentColorLight1}" />
       <StaticResource x:Key="SplitButtonBackgroundCheckedDisabled" ResourceKey="SystemControlBackgroundBaseLowBrush" />
       <StaticResource x:Key="SplitButtonForeground" ResourceKey="SystemControlForegroundBaseHighBrush" />
       <StaticResource x:Key="SplitButtonForegroundPointerOver" ResourceKey="SystemControlHighlightBaseHighBrush" />

src/Avalonia.Themes.Fluent/Accents/SystemAccentColors.cs

@@ -0,0 +1,163 @@
+using System;
+using Avalonia.Controls;
+using Avalonia.Media;
+using Avalonia.Platform;
+using Avalonia.Styling;
+
+namespace Avalonia.Themes.Fluent.Accents;
+
+internal class SystemAccentColors : IResourceProvider
+{
+    public const string AccentKey = "SystemAccentColor";
+    public const string AccentDark1Key = "SystemAccentColorDark1";
+    public const string AccentDark2Key = "SystemAccentColorDark2";
+    public const string AccentDark3Key = "SystemAccentColorDark3";
+    public const string AccentLight1Key = "SystemAccentColorLight1";
+    public const string AccentLight2Key = "SystemAccentColorLight2";
+    public const string AccentLight3Key = "SystemAccentColorLight3";
+    
+    private static readonly Color s_defaultSystemAccentColor = Color.FromRgb(0, 120, 215); 
+    private readonly IPlatformSettings? _platformSettings;
+    private bool _invalidateColors = true;
+    private Color _systemAccentColor;
+    private Color _systemAccentColorDark1, _systemAccentColorDark2, _systemAccentColorDark3;
+    private Color _systemAccentColorLight1, _systemAccentColorLight2, _systemAccentColorLight3;
+
+    public SystemAccentColors()
+    {
+        _platformSettings = AvaloniaLocator.Current.GetService<IPlatformSettings>();
+    }
+    
+    public bool HasResources => true;
+    public bool TryGetResource(object key, ThemeVariant? theme, out object? value)
+    {
+        if (key is string strKey)
+        {
+            if (strKey.Equals(AccentKey, StringComparison.InvariantCulture))
+            {
+                EnsureColors();
+                value = _systemAccentColor;
+                return true;
+            }
+
+            if (strKey.Equals(AccentDark1Key, StringComparison.InvariantCulture))
+            {
+                EnsureColors();
+                value = _systemAccentColorDark1;
+                return true;
+            }
+
+            if (strKey.Equals(AccentDark2Key, StringComparison.InvariantCulture))
+            {
+                EnsureColors();
+                value = _systemAccentColorDark2;
+                return true;
+            }
+
+            if (strKey.Equals(AccentDark3Key, StringComparison.InvariantCulture))
+            {
+                EnsureColors();
+                value = _systemAccentColorDark3;
+                return true;
+            }
+
+            if (strKey.Equals(AccentLight1Key, StringComparison.InvariantCulture))
+            {
+                EnsureColors();
+                value = _systemAccentColorLight1;
+                return true;
+            }
+
+            if (strKey.Equals(AccentLight2Key, StringComparison.InvariantCulture))
+            {
+                EnsureColors();
+                value = _systemAccentColorLight2;
+                return true;
+            }
+
+            if (strKey.Equals(AccentLight3Key, StringComparison.InvariantCulture))
+            {
+                EnsureColors();
+                value = _systemAccentColorLight3;
+                return true;
+            }
+        }
+
+        value = null;
+        return false;
+    }
+
+    public IResourceHost? Owner { get; private set; }
+    public event EventHandler? OwnerChanged;
+    public void AddOwner(IResourceHost owner)
+    {
+        if (Owner != owner)
+        {
+            Owner = owner;
+            OwnerChanged?.Invoke(this, EventArgs.Empty);
+
+            if (_platformSettings is not null)
+            {
+                _platformSettings.ColorValuesChanged += PlatformSettingsOnColorValuesChanged;
+            }
+        }
+    }
+
+    public void RemoveOwner(IResourceHost owner)
+    {
+        if (Owner == owner)
+        {
+            Owner = null;
+            OwnerChanged?.Invoke(this, EventArgs.Empty);
+            
+            if (_platformSettings is not null)
+            {
+                _platformSettings.ColorValuesChanged -= PlatformSettingsOnColorValuesChanged;
+            }
+        }
+    }
+
+    private void EnsureColors()
+    {
+        if (_invalidateColors)
+        {
+            _invalidateColors = false;
+            
+            _systemAccentColor = _platformSettings?.GetColorValues().AccentColor1 ?? s_defaultSystemAccentColor;
+            (_systemAccentColorDark1,_systemAccentColorDark2, _systemAccentColorDark3,
+                    _systemAccentColorLight1, _systemAccentColorLight2, _systemAccentColorLight3) = CalculateAccentShades(_systemAccentColor);
+        }
+    }
+
+    public static (Color d1, Color d2, Color d3, Color l1, Color l2, Color l3) CalculateAccentShades(Color accentColor)
+    {
+        // dark1step = (hslAccent.L - SystemAccentColorDark1.L) * 255
+        const double dark1step = 28.5 / 255d;
+        const double dark2step = 49 / 255d;
+        const double dark3step = 74.5 / 255d;
+        // light1step = (SystemAccentColorLight1.L - hslAccent.L) * 255
+        const double light1step = 39 / 255d;
+        const double light2step = 70 / 255d;
+        const double light3step = 103 / 255d;
+        
+        var hslAccent = accentColor.ToHsl();
+
+        return (
+            // Darker shades
+            new HslColor(hslAccent.A, hslAccent.H, hslAccent.S, hslAccent.L - dark1step).ToRgb(),
+            new HslColor(hslAccent.A, hslAccent.H, hslAccent.S, hslAccent.L - dark2step).ToRgb(),
+            new HslColor(hslAccent.A, hslAccent.H, hslAccent.S, hslAccent.L - dark3step).ToRgb(),
+
+            // Lighter shades
+            new HslColor(hslAccent.A, hslAccent.H, hslAccent.S, hslAccent.L + light1step).ToRgb(),
+            new HslColor(hslAccent.A, hslAccent.H, hslAccent.S, hslAccent.L + light2step).ToRgb(),
+            new HslColor(hslAccent.A, hslAccent.H, hslAccent.S, hslAccent.L + light3step).ToRgb()
+        );
+    }
+    
+    private void PlatformSettingsOnColorValuesChanged(object? sender, PlatformColorValues e)
+    {
+        _invalidateColors = true;
+        Owner?.NotifyHostedResourcesChanged(ResourcesChangedEventArgs.Empty);
+    }
+}

src/Avalonia.Themes.Fluent/ColorPaletteResources.Properties.cs

@@ -0,0 +1,158 @@
+using Avalonia.Media;
+
+namespace Avalonia.Themes.Fluent;
+
+public partial class ColorPaletteResources
+{
+    private bool _hasAccentColor;
+    private Color _accentColor;
+    private Color _accentColorDark1, _accentColorDark2, _accentColorDark3;
+    private Color _accentColorLight1, _accentColorLight2, _accentColorLight3;
+
+    public static readonly DirectProperty<ColorPaletteResources, Color> AccentProperty
+        = AvaloniaProperty.RegisterDirect<ColorPaletteResources, Color>(nameof(Accent), r => r.Accent, (r, v) => r.Accent = v);
+
+    /// <summary>
+    /// Gets or sets the Accent color value.
+    /// </summary>
+    public Color Accent
+    {
+        get => _accentColor;
+        set => SetAndRaise(AccentProperty, ref _accentColor, value);
+    }
+
+    /// <summary>
+    /// Gets or sets the AltHigh color value.
+    /// </summary>
+    public Color AltHigh { get => GetColor("SystemAltHighColor"); set => SetColor("SystemAltHighColor", value); }
+
+    /// <summary>
+    /// Gets or sets the AltLow color value.
+    /// </summary>
+    public Color AltLow { get => GetColor("SystemAltLowColor"); set => SetColor("SystemAltLowColor", value); }
+
+    /// <summary>
+    /// Gets or sets the AltMedium color value.
+    /// </summary>
+    public Color AltMedium { get => GetColor("SystemAltMediumColor"); set => SetColor("SystemAltMediumColor", value); }
+
+    /// <summary>
+    /// Gets or sets the AltMediumHigh color value.
+    /// </summary>
+    public Color AltMediumHigh { get => GetColor("SystemAltMediumHighColor"); set => SetColor("SystemAltMediumHighColor", value); }
+
+    /// <summary>
+    /// Gets or sets the AltMediumLow color value.
+    /// </summary>
+    public Color AltMediumLow { get => GetColor("SystemAltMediumLowColor"); set => SetColor("SystemAltMediumLowColor", value); }
+
+    /// <summary>
+    /// Gets or sets the BaseHigh color value.
+    /// </summary>
+    public Color BaseHigh { get => GetColor("SystemBaseHighColor"); set => SetColor("SystemBaseHighColor", value); }
+
+    /// <summary>
+    /// Gets or sets the BaseLow color value.
+    /// </summary>
+    public Color BaseLow { get => GetColor("SystemBaseLowColor"); set => SetColor("SystemBaseLowColor", value); }
+
+    /// <summary>
+    /// Gets or sets the BaseMedium color value.
+    /// </summary>
+    public Color BaseMedium { get => GetColor("SystemBaseMediumColor"); set => SetColor("SystemBaseMediumColor", value); }
+
+    /// <summary>
+    /// Gets or sets the BaseMediumHigh color value.
+    /// </summary>
+    public Color BaseMediumHigh { get => GetColor("SystemBaseMediumHighColor"); set => SetColor("SystemBaseMediumHighColor", value); }
+
+    /// <summary>
+    /// Gets or sets the BaseMediumLow color value.
+    /// </summary>
+    public Color BaseMediumLow { get => GetColor("SystemBaseMediumLowColor"); set => SetColor("SystemBaseMediumLowColor", value); }
+
+    /// <summary>
+    /// Gets or sets the ChromeAltLow color value.
+    /// </summary>
+    public Color ChromeAltLow { get => GetColor("SystemChromeAltLowColor"); set => SetColor("SystemChromeAltLowColor", value); }
+
+    /// <summary>
+    /// Gets or sets the ChromeBlackHigh color value.
+    /// </summary>
+    public Color ChromeBlackHigh { get => GetColor("SystemChromeBlackHighColor"); set => SetColor("SystemChromeBlackHighColor", value); }
+
+    /// <summary>
+    /// Gets or sets the ChromeBlackLow color value.
+    /// </summary>
+    public Color ChromeBlackLow { get => GetColor("SystemChromeBlackLowColor"); set => SetColor("SystemChromeBlackLowColor", value); }
+
+    /// <summary>
+    /// Gets or sets the ChromeBlackMedium color value.
+    /// </summary>
+    public Color ChromeBlackMedium { get => GetColor("SystemChromeBlackMediumColor"); set => SetColor("SystemChromeBlackMediumColor", value); }
+
+    /// <summary>
+    /// Gets or sets the ChromeBlackMediumLow color value.
+    /// </summary>
+    public Color ChromeBlackMediumLow { get => GetColor("SystemChromeBlackMediumLowColor"); set => SetColor("SystemChromeBlackMediumLowColor", value); }
+
+    /// <summary>
+    /// Gets or sets the ChromeDisabledHigh color value.
+    /// </summary>
+    public Color ChromeDisabledHigh { get => GetColor("SystemChromeDisabledHighColor"); set => SetColor("SystemChromeDisabledHighColor", value); }
+
+    /// <summary>
+    /// Gets or sets the ChromeDisabledLow color value.
+    /// </summary>
+    public Color ChromeDisabledLow { get => GetColor("SystemChromeDisabledLowColor"); set => SetColor("SystemChromeDisabledLowColor", value); }
+
+    /// <summary>
+    /// Gets or sets the ChromeGray color value.
+    /// </summary>
+    public Color ChromeGray { get => GetColor("SystemChromeGrayColor"); set => SetColor("SystemChromeGrayColor", value); }
+
+    /// <summary>
+    /// Gets or sets the ChromeHigh color value.
+    /// </summary>
+    public Color ChromeHigh { get => GetColor("SystemChromeHighColor"); set => SetColor("SystemChromeHighColor", value); }
+
+    /// <summary>
+    /// Gets or sets the ChromeLow color value.
+    /// </summary>
+    public Color ChromeLow { get => GetColor("SystemChromeLowColor"); set => SetColor("SystemChromeLowColor", value); }
+
+    /// <summary>
+    /// Gets or sets the ChromeMedium color value.
+    /// </summary>
+    public Color ChromeMedium { get => GetColor("SystemChromeMediumColor"); set => SetColor("SystemChromeMediumColor", value); }
+
+    /// <summary>
+    /// Gets or sets the ChromeMediumLow color value.
+    /// </summary>
+    public Color ChromeMediumLow { get => GetColor("SystemChromeMediumLowColor"); set => SetColor("SystemChromeMediumLowColor", value); }
+
+    /// <summary>
+    /// Gets or sets the ChromeWhite color value.
+    /// </summary>
+    public Color ChromeWhite { get => GetColor("SystemChromeWhiteColor"); set => SetColor("SystemChromeWhiteColor", value); }
+
+    /// <summary>
+    /// Gets or sets the ErrorText color value.
+    /// </summary>
+    public Color ErrorText { get => GetColor("SystemErrorTextColor"); set => SetColor("SystemErrorTextColor", value); }
+
+    /// <summary>
+    /// Gets or sets the ListLow color value.
+    /// </summary>
+    public Color ListLow { get => GetColor("SystemListLowColor"); set => SetColor("SystemListLowColor", value); }
+
+    /// <summary>
+    /// Gets or sets the ListMedium color value.
+    /// </summary>
+    public Color ListMedium { get => GetColor("SystemListMediumColor"); set => SetColor("SystemListMediumColor", value); }
+    
+    /// <summary>
+    /// Gets or sets the RegionColor color value.
+    /// </summary>
+    public Color RegionColor { get => GetColor("SystemRegionColor"); set => SetColor("SystemRegionColor", value); }
+}

src/Avalonia.Themes.Fluent/ColorPaletteResources.cs

@@ -0,0 +1,118 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Avalonia.Controls;
+using Avalonia.Media;
+using Avalonia.Styling;
+using Avalonia.Themes.Fluent.Accents;
+
+namespace Avalonia.Themes.Fluent;
+
+/// <summary>
+/// Represents a specialized resource dictionary that contains color resources used by FluentTheme elements.
+/// </summary>
+/// <remarks>
+/// This class can only be used in <see cref="FluentTheme.Palettes"/>.
+/// </remarks>
+public partial class ColorPaletteResources : AvaloniaObject, IResourceNode
+{
+    private readonly Dictionary<string, Color> _colors = new(StringComparer.InvariantCulture);
+
+    public bool HasResources => _hasAccentColor || _colors.Count > 0;
+
+    public bool TryGetResource(object key, ThemeVariant? theme, out object? value)
+    {
+        if (key is string strKey)
+        {
+            if (strKey.Equals(SystemAccentColors.AccentKey, StringComparison.InvariantCulture))
+            {
+                value = _accentColor;
+                return _hasAccentColor;
+            }
+
+            if (strKey.Equals(SystemAccentColors.AccentDark1Key, StringComparison.InvariantCulture))
+            {
+                value = _accentColorDark1;
+                return _hasAccentColor;
+            }
+
+            if (strKey.Equals(SystemAccentColors.AccentDark2Key, StringComparison.InvariantCulture))
+            {
+                value = _accentColorDark2;
+                return _hasAccentColor;
+            }
+
+            if (strKey.Equals(SystemAccentColors.AccentDark3Key, StringComparison.InvariantCulture))
+            {
+                value = _accentColorDark3;
+                return _hasAccentColor;
+            }
+
+            if (strKey.Equals(SystemAccentColors.AccentLight1Key, StringComparison.InvariantCulture))
+            {
+                value = _accentColorLight1;
+                return _hasAccentColor;
+            }
+
+            if (strKey.Equals(SystemAccentColors.AccentLight2Key, StringComparison.InvariantCulture))
+            {
+                value = _accentColorLight2;
+                return _hasAccentColor;
+            }
+
+            if (strKey.Equals(SystemAccentColors.AccentLight3Key, StringComparison.InvariantCulture))
+            {
+                value = _accentColorLight3;
+                return _hasAccentColor;
+            }
+
+            if (_colors.TryGetValue(strKey, out var color))
+            {
+                value = color;
+                return true;
+            }
+        }
+
+        value = null;
+        return false;
+    }
+
+    private Color GetColor(string key)
+    {
+        if (_colors.TryGetValue(key, out var color))
+        {
+            return color;
+        }
+
+        return default;
+    }
+    
+    private void SetColor(string key, Color value)
+    {
+        if (value == default)
+        {
+            _colors.Remove(key);
+        }
+        else
+        {
+            _colors[key] = value;
+        }
+    }
+
+    protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs change)
+    {
+        base.OnPropertyChanged(change);
+
+        if (change.Property == AccentProperty)
+        {
+            _hasAccentColor = _accentColor != default;
+
+            if (_hasAccentColor)
+            {
+                (_accentColorDark1, _accentColorDark2, _accentColorDark3,
+                        _accentColorLight1, _accentColorLight2, _accentColorLight3) =
+                    SystemAccentColors.CalculateAccentShades(_accentColor);
+            }
+        }
+    }
+}

src/Avalonia.Themes.Fluent/ColorPaletteResourcesCollection.cs

@@ -0,0 +1,65 @@
+using System;
+using Avalonia.Collections;
+using Avalonia.Controls;
+using Avalonia.Styling;
+
+namespace Avalonia.Themes.Fluent;
+
+internal class ColorPaletteResourcesCollection : AvaloniaDictionary<ThemeVariant, ColorPaletteResources>, IResourceProvider
+{
+    public ColorPaletteResourcesCollection() : base(2)
+    {
+        this.ForEachItem(
+            (_, x) =>
+            {
+                if (Owner is not null)
+                {
+                    x.PropertyChanged += Palette_PropertyChanged;
+                }
+            },
+            (_, x) =>
+            {
+                if (Owner is not null)
+                {
+                    x.PropertyChanged -= Palette_PropertyChanged;
+                }
+            },
+            () => throw new NotSupportedException("Dictionary reset not supported"));
+    }
+
+    public bool HasResources => Count > 0;
+    public bool TryGetResource(object key, ThemeVariant? theme, out object? value)
+    {
+        theme ??= ThemeVariant.Default;
+        if (base.TryGetValue(theme, out var paletteResources)
+            && paletteResources.TryGetResource(key, theme, out value))
+        {
+            return true;
+        }
+
+        value = null;
+        return false;
+    }
+
+    public IResourceHost? Owner { get; private set; }
+    public event EventHandler? OwnerChanged;
+    public void AddOwner(IResourceHost owner)
+    {
+        Owner = owner;
+        OwnerChanged?.Invoke(this, EventArgs.Empty);
+    }
+
+    public void RemoveOwner(IResourceHost owner)
+    {
+        Owner = null;
+        OwnerChanged?.Invoke(this, EventArgs.Empty);
+    }
+            
+    private void Palette_PropertyChanged(object? sender, AvaloniaPropertyChangedEventArgs e)
+    {
+        if (e.Property == ColorPaletteResources.AccentProperty)
+        {
+            Owner?.NotifyHostedResourcesChanged(ResourcesChangedEventArgs.Empty);
+        }
+    }
+}

src/Avalonia.Themes.Fluent/Controls/EmbeddableControlRoot.xaml

@@ -2,7 +2,7 @@
                     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
   <ControlTheme x:Key="{x:Type EmbeddableControlRoot}" TargetType="EmbeddableControlRoot">
     <Setter Property="Foreground" Value="{DynamicResource SystemControlForegroundBaseHighBrush}"/>
-    <Setter Property="Background" Value="{DynamicResource SystemControlBackgroundAltHighBrush}"/>
+    <Setter Property="Background" Value="{DynamicResource SystemRegionBrush}"/>
     <Setter Property="TopLevel.SystemBarColor" Value="{DynamicResource SystemControlBackgroundAltHighBrush}"/>
     <Setter Property="FontSize" Value="{DynamicResource ControlContentThemeFontSize}"/>
     <Setter Property="FontFamily" Value="{DynamicResource ContentControlThemeFontFamily}" />

src/Avalonia.Themes.Fluent/Controls/Window.xaml

@@ -1,7 +1,7 @@
 <ResourceDictionary xmlns="https://github.com/avaloniaui"
                     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
   <ControlTheme x:Key="{x:Type Window}" TargetType="Window">
-    <Setter Property="Background" Value="{DynamicResource SystemControlBackgroundAltHighBrush}"/>
+    <Setter Property="Background" Value="{DynamicResource SystemRegionBrush}"/>
     <Setter Property="TransparencyBackgroundFallback" Value="{DynamicResource SystemControlBackgroundAltHighBrush}" />
     <Setter Property="TopLevel.SystemBarColor" Value="{DynamicResource SystemControlBackgroundAltHighBrush}"/>
     <Setter Property="Foreground" Value="{DynamicResource SystemControlForegroundBaseHighBrush}"/>

src/Avalonia.Themes.Fluent/FluentTheme.xaml

@@ -1,11 +1,19 @@
 <Styles x:Class="Avalonia.Themes.Fluent.FluentTheme"
         xmlns="https://github.com/avaloniaui"
-        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:fluent="using:Avalonia.Themes.Fluent"
+        xmlns:accents="clr-namespace:Avalonia.Themes.Fluent.Accents">
   <Styles.Resources>
     <ResourceDictionary>
       <ResourceDictionary.MergedDictionaries>
-        <MergeResourceInclude Source="/Accents/AccentColors.xaml" />
-        <MergeResourceInclude Source="/Accents/Base.xaml" />
+        <!-- Keep custom palettes higher priority than default BaseColorsPalette and SystemAccentColors
+             As that's an only place for user to redefine palette in a good way -->
+        <ResourceInclude Source="/Accents/BaseColorsPalette.xaml" />
+        <accents:SystemAccentColors />
+        <fluent:ColorPaletteResourcesCollection />
+
+        <!-- Resources and brushes will be merged into current dictionary for slightly better performance and possible optimizations -->
+        <MergeResourceInclude Source="/Accents/BaseResources.xaml" />
         <MergeResourceInclude Source="/Accents/FluentControlResources.xaml" />
       </ResourceDictionary.MergedDictionaries>
       

src/Avalonia.Themes.Fluent/FluentTheme.xaml.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using Avalonia.Controls;
 using Avalonia.Markup.Xaml;
 using Avalonia.Styling;
@@ -31,6 +32,9 @@ namespace Avalonia.Themes.Fluent
 
             EnsureCompactStyles();
 
+            Palettes = Resources.MergedDictionaries.OfType<ColorPaletteResourcesCollection>().FirstOrDefault()
+                ?? throw new InvalidOperationException("FluentTheme was initialized with missing ColorPaletteResourcesCollection.");
+            
             object GetAndRemove(string key)
             {
                 var val = Resources[key]
@@ -52,6 +56,8 @@ namespace Avalonia.Themes.Fluent
             set => SetValue(DensityStyleProperty, value);
         }
         
+        public IDictionary<ThemeVariant, ColorPaletteResources> Palettes { get; }
+
         protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs change)
         {
             base.OnPropertyChanged(change);

src/Markup/Avalonia.Markup.Xaml.Loader/CompilerExtensions/GroupTransformers/XamlMergeResourceGroupTransformer.cs

@@ -24,7 +24,7 @@ internal class XamlMergeResourceGroupTransformer : IXamlAstGroupTransformer
 
         var mergeResourceIncludeType = context.GetAvaloniaTypes().MergeResourceInclude;
         var mergeSourceNodes = new List<XamlPropertyAssignmentNode>();
-        var hasAnyNonMergedResource = false;
+        var mergedResourceWasAdded = false;
         foreach (var manipulationNode in resourceDictionaryManipulation.Children.ToArray())
         {
             void ProcessXamlPropertyAssignmentNode(XamlManipulationGroupNode parent, XamlPropertyAssignmentNode assignmentNode)
@@ -38,7 +38,8 @@ internal class XamlMergeResourceGroupTransformer : IXamlAstGroupTransformer
                             && objectInitialization.Manipulation is XamlPropertyAssignmentNode sourceAssignmentNode)
                         {
                             parent.Children.Remove(assignmentNode);
-                            mergeSourceNodes.Add(sourceAssignmentNode);   
+                            mergeSourceNodes.Add(sourceAssignmentNode);
+                            mergedResourceWasAdded = true;
                         }
                         else
                         {
@@ -47,15 +48,10 @@ internal class XamlMergeResourceGroupTransformer : IXamlAstGroupTransformer
                                 valueNode);
                         }
                     }
-                    else
-                    {
-                        hasAnyNonMergedResource = true;
-                    }
-
-                    if (hasAnyNonMergedResource && mergeSourceNodes.Any())
+                    else if (mergeSourceNodes.Any())
                     {
                         throw new XamlDocumentParseException(context.CurrentDocument,
-                            "Mix of MergeResourceInclude and other dictionaries inside of the ResourceDictionary.MergedDictionaries is not allowed",
+                            "MergeResourceInclude should always be included last when mixing with other dictionaries inside of the ResourceDictionary.MergedDictionaries.",
                             valueNode);
                     }
                 }

tests/Avalonia.Markup.Xaml.UnitTests/Xaml/MergeResourceIncludeTests.cs

@@ -83,6 +83,34 @@ public class MergeResourceIncludeTests
         Assert.ThrowsAny<XmlException>(() => AvaloniaRuntimeXamlLoader.LoadGroup(documents));
     }
     
+    [Fact]
+    public void MergeResourceInclude_Is_Allowed_After_ResourceInclude()
+    {
+        var documents = new[]
+        {
+            new RuntimeXamlLoaderDocument(new Uri("avares://Tests/Resources1.xaml"), @"
+<ResourceDictionary xmlns='https://github.com/avaloniaui'
+                    xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'>
+    <SolidColorBrush x:Key='brush1'>Red</SolidColorBrush>
+</ResourceDictionary>"),
+            new RuntimeXamlLoaderDocument(new Uri("avares://Tests/Resources2.xaml"), @"
+<ResourceDictionary xmlns='https://github.com/avaloniaui'
+                    xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'>
+    <SolidColorBrush x:Key='brush2'>Blue</SolidColorBrush>
+</ResourceDictionary>"),
+            new RuntimeXamlLoaderDocument(@"
+<ResourceDictionary xmlns='https://github.com/avaloniaui'
+                    xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'>
+    <ResourceDictionary.MergedDictionaries>
+        <ResourceInclude Source='avares://Tests/Resources2.xaml'/>
+        <MergeResourceInclude Source='avares://Tests/Resources1.xaml'/>
+    </ResourceDictionary.MergedDictionaries>
+</ResourceDictionary>")
+        };
+        
+        AvaloniaRuntimeXamlLoader.LoadGroup(documents);
+    }
+    
     [Fact]
     public void MergeResourceInclude_Works_With_Multiple_Resources()
     {