fix window colours.

samples/ControlCatalog/MainWindow.xaml

@@ -10,10 +10,9 @@
         ExtendClientAreaToDecorationsHint="{Binding ExtendClientAreaEnabled}"
         ExtendClientAreaChromeHints="{Binding ChromeHints}"
         ExtendClientAreaTitleBarHeightHint="{Binding TitleBarHeight}"
-        TransparencyLevelHint="{Binding TransparencyLevel}"
-        TransparencyBackgroundFallback="Transparent"
+        TransparencyLevelHint="{Binding TransparencyLevel}"        
         x:Name="MainWindow"
-        x:Class="ControlCatalog.MainWindow" WindowState="{Binding WindowState, Mode=TwoWay}" Background="{x:Null}">
+        x:Class="ControlCatalog.MainWindow" WindowState="{Binding WindowState, Mode=TwoWay}">
   <NativeMenu.Menu>
     <NativeMenu>
       <NativeMenuItem Header="File">
@@ -69,7 +68,7 @@
   </Window.DataTemplates>
   <Panel>
     <Panel Margin="{Binding #MainWindow.OffScreenMargin}">
-      <DockPanel Background="{DynamicResource SystemControlBackgroundChromeBlackHighBrush}" LastChildFill="True" Margin="{Binding #MainWindow.WindowDecorationMargin}">
+      <DockPanel LastChildFill="True" Margin="{Binding #MainWindow.WindowDecorationMargin}">
         <Menu Name="MainMenu" DockPanel.Dock="Top">
           <MenuItem Header="File">
             <MenuItem Header="Exit" Command="{Binding ExitCommand}" />

src/Avalonia.Themes.Fluent/Avalonia.Themes.Fluent.csproj

@@ -12,7 +12,9 @@
     <ProjectReference Include="..\Avalonia.Layout\Avalonia.Layout.csproj" />
     <ProjectReference Include="..\Avalonia.Visuals\Avalonia.Visuals.csproj" />
     <ProjectReference Include="..\Avalonia.Styling\Avalonia.Styling.csproj" />    
-    <AvaloniaResource Include="**/*.xaml" />    
+    <AvaloniaResource Include="**/*.xaml" />
+    <AvaloniaResource Include="Assets\*" />
+  </ItemGroup>
   </ItemGroup>
   <Import Project="..\..\build\BuildTargets.targets" />
   <Import Project="..\..\build\Rx.props" />

src/Avalonia.Themes.Fluent/Window.xaml

@@ -1,7 +1,9 @@
 <Style xmlns="https://github.com/avaloniaui" Selector="Window">
-  <Setter Property="Background" Value="{DynamicResource SystemControlBackgroundChromeBlackHighBrush}"/>  
-  <Setter Property="Foreground" Value="{DynamicResource ThemeForegroundBrush}"/>
-  <Setter Property="FontSize" Value="{DynamicResource FontSizeNormal}"/>
+  <Setter Property="Background" Value="{DynamicResource SystemControlBackgroundAltHighBrush}"/>  
+  <Setter Property="TransparencyBackgroundFallback" Value="{DynamicResource SystemControlBackgroundAltHighBrush}" />
+  <Setter Property="Foreground" Value="{DynamicResource SystemControlForegroundBaseHighBrush}"/>
+  <Setter Property="FontSize" Value="{DynamicResource ContentControlFontSize}"/>  
+  <Setter Property="FontFamily" Value="{DynamicResource ContentControlThemeFontFamily}" />
   <Setter Property="Template">
     <ControlTemplate>
       <Panel>