chore: remove redundant background.

src/Avalonia/HandyControlDemo_Avalonia/UserControl/Styles/BorderDemo.axaml

@@ -1,8 +1,7 @@
 <UserControl xmlns="https://github.com/avaloniaui"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              xmlns:hc="https://handyorg.github.io/handycontrol"
-             x:Class="HandyControlDemo.UserControl.BorderDemo"
+             x:Class="HandyControlDemo.UserControl.BorderDemo">
-             Background="{DynamicResource RegionBrush}">
     <ScrollViewer>
         <hc:UniformSpacingPanel Margin="32"
                                 Orientation="Vertical"

src/Avalonia/HandyControlDemo_Avalonia/UserControl/Styles/BrushDemo.axaml

@@ -1,8 +1,7 @@
 <UserControl xmlns="https://github.com/avaloniaui"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              xmlns:hc="https://handyorg.github.io/handycontrol"
-             x:Class="HandyControlDemo.UserControl.BrushDemo"
+             x:Class="HandyControlDemo.UserControl.BrushDemo">
-             Background="{DynamicResource RegionBrush}">
     <ScrollViewer>
         <hc:UniformSpacingPanel ChildWrapping="Wrap"
                                 ItemWidth="200"

src/Avalonia/HandyControlDemo_Avalonia/UserControl/Styles/ButtonDemo.axaml

@@ -1,8 +1,7 @@
 <UserControl xmlns="https://github.com/avaloniaui"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              x:Class="HandyControlDemo.UserControl.ButtonDemo"
-             xmlns:hc="https://handyorg.github.io/handycontrol"
+             xmlns:hc="https://handyorg.github.io/handycontrol">
-             Background="{DynamicResource RegionBrush}">
     <ScrollViewer>
         <hc:UniformSpacingPanel ChildWrapping="Wrap"
                                 Spacing="32"

src/Avalonia/HandyControlDemo_Avalonia/UserControl/Styles/CalendarDemo.axaml

@@ -1,7 +1,6 @@
 <UserControl xmlns="https://github.com/avaloniaui"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-             x:Class="HandyControlDemo.UserControl.CalendarDemo"
+             x:Class="HandyControlDemo.UserControl.CalendarDemo">
-             Background="{DynamicResource RegionBrush}">
     <Calendar Margin="32"
               SelectionMode="MultipleRange" />
 </UserControl>

src/Avalonia/HandyControlDemo_Avalonia/UserControl/Styles/NativeScrollViewerDemo.axaml

@@ -2,7 +2,6 @@
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              x:Class="HandyControlDemo.UserControl.NativeScrollViewerDemo"
              xmlns:hc="https://handyorg.github.io/handycontrol"
-             Background="{DynamicResource RegionBrush}"
              MaxWidth="550"
              Height="600">
     <Grid Margin="32"

src/Avalonia/HandyControlDemo_Avalonia/UserControl/Styles/RadioButtonDemo.axaml

@@ -1,8 +1,7 @@
 <UserControl xmlns="https://github.com/avaloniaui"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              x:Class="HandyControlDemo.UserControl.RadioButtonDemo"
-             xmlns:hc="https://handyorg.github.io/handycontrol"
+             xmlns:hc="https://handyorg.github.io/handycontrol">
-             Background="{DynamicResource RegionBrush}">
     <ScrollViewer>
         <hc:UniformSpacingPanel ChildWrapping="Wrap"
                                 Spacing="32"

src/Avalonia/HandyControlDemo_Avalonia/UserControl/Styles/RepeatButtonDemo.axaml

@@ -1,8 +1,7 @@
 <UserControl xmlns="https://github.com/avaloniaui"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              x:Class="HandyControlDemo.UserControl.RepeatButtonDemo"
-             xmlns:hc="https://handyorg.github.io/handycontrol"
+             xmlns:hc="https://handyorg.github.io/handycontrol">
-             Background="{DynamicResource RegionBrush}">
     <ScrollViewer>
         <hc:UniformSpacingPanel ChildWrapping="Wrap"
                                 Spacing="32"

src/Avalonia/HandyControlDemo_Avalonia/UserControl/Styles/SliderDemo.axaml

@@ -1,8 +1,7 @@
 <UserControl xmlns="https://github.com/avaloniaui"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              x:Class="HandyControlDemo.UserControl.SliderDemo"
-             xmlns:hc="https://handyorg.github.io/handycontrol"
+             xmlns:hc="https://handyorg.github.io/handycontrol">
-             Background="{DynamicResource RegionBrush}">
     <ScrollViewer>
         <hc:UniformSpacingPanel Margin="32"
                                 Orientation="Horizontal"

src/Avalonia/HandyControlDemo_Avalonia/UserControl/Styles/TextBlockDemo.axaml

@@ -1,8 +1,7 @@
 <UserControl xmlns="https://github.com/avaloniaui"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              xmlns:hc="https://handyorg.github.io/handycontrol"
-             x:Class="HandyControlDemo.UserControl.TextBlockDemo"
+             x:Class="HandyControlDemo.UserControl.TextBlockDemo">
-             Background="{DynamicResource RegionBrush}">
     <ScrollViewer>
         <hc:UniformSpacingPanel Margin="32"
                                 Spacing="5"

src/Avalonia/HandyControlDemo_Avalonia/UserControl/Styles/ToggleButtonDemo.axaml

@@ -1,8 +1,7 @@
 <UserControl xmlns="https://github.com/avaloniaui"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              x:Class="HandyControlDemo.UserControl.ToggleButtonDemo"
-             xmlns:hc="https://handyorg.github.io/handycontrol"
+             xmlns:hc="https://handyorg.github.io/handycontrol">
-             Background="{DynamicResource RegionBrush}">
     <ScrollViewer>
         <hc:UniformSpacingPanel ChildWrapping="Wrap"
                                 Spacing="32"