BaldeView use WinUI themes.

BladeViewItem
use CardBackgroundFillColorDefaultBrush for background.
use CardStrokeColorDefaultBrush for BorderBrush.

Author: Rosuavio

Microsoft.Toolkit.Uwp.UI.Controls.Layout/BladeView/BladeView.xaml

@@ -89,7 +89,7 @@
         <Setter Property="FontFamily" Value="{ThemeResource ContentControlThemeFontFamily}" />
         <Setter Property="FontSize" Value="{ThemeResource ControlContentThemeFontSize}" />
         <Setter Property="TitleBarBackground" Value="{ThemeResource SystemControlBackgroundChromeMediumLowBrush}" />
-        <Setter Property="Background" Value="{ThemeResource SystemControlBackgroundAltHighBrush}" />
+        <Setter Property="Background" Value="{ThemeResource CardBackgroundFillColorDefaultBrush}" />
         <Setter Property="Foreground" Value="{ThemeResource SystemControlForegroundBaseHighBrush}" />
         <Setter Property="TabNavigation" Value="Local" />
         <Setter Property="IsHoldingEnabled" Value="True" />
@@ -99,7 +99,7 @@
         <Setter Property="Margin" Value="0" />
         <Setter Property="MinWidth" Value="{ThemeResource GridViewItemMinWidth}" />
         <Setter Property="MinHeight" Value="{ThemeResource GridViewItemMinHeight}" />
-        <Setter Property="BorderBrush" Value="{ThemeResource SystemControlForegroundChromeHighBrush}" />
+        <Setter Property="BorderBrush" Value="{ThemeResource CardStrokeColorDefaultBrush}" />
         <Setter Property="BorderThickness" Value="1" />
         <Setter Property="IsTabStop" Value="False" />
         <Setter Property="IsExpanded" Value="True"/>