修正NavigationView的Style

src/App/Styles/Style.Overwrite.xaml

@@ -8,6 +8,7 @@
     <Thickness x:Key="TopNavigationViewTopNavGridMargin">0</Thickness>
     <SolidColorBrush x:Key="NavigationViewTopPaneBackground" Color="Transparent" />
     <SolidColorBrush x:Key="NavigationViewContentBackground" Color="Transparent" />
+    <SolidColorBrush x:Key="NavigationViewExpandedPaneBackground" Color="Transparent"/>
 
     <Style x:Key="PageProgressRingStyle" TargetType="muxc:ProgressRing">
         <Setter Property="Width" Value="32" />