Update background color of selected ListView item to meet contrast ratio requirement (microsoft/microsoft-ui-xaml#2962)

Author: Kinnara

ModernWpf/ThemeResources/Dark.xaml

@@ -120,6 +120,8 @@
     <SolidColorBrush x:Key="SystemControlHighlightListAccentHighBrush" Color="{m:DynamicColor SystemAccentColor}" Opacity="0.9" />
     <SolidColorBrush x:Key="SystemControlHighlightListAccentLowBrush" Color="{m:DynamicColor SystemAccentColor}" Opacity="0.6" />
     <SolidColorBrush x:Key="SystemControlHighlightListAccentMediumBrush" Color="{m:DynamicColor SystemAccentColor}" Opacity="0.8" />
+    <SolidColorBrush x:Key="SystemControlHighlightListAccentVeryHighBrush" Color="{m:DynamicColor SystemAccentColor}" Opacity="0.9" />
+    <SolidColorBrush x:Key="SystemControlHighlightListAccentMediumLowBrush" Color="{m:DynamicColor SystemAccentColor}" Opacity="0.75" />
     <SolidColorBrush x:Key="SystemControlHighlightListMediumBrush" Color="{m:StaticColor SystemListMediumColor}" />
     <SolidColorBrush x:Key="SystemControlHighlightListLowBrush" Color="{m:StaticColor SystemListLowColor}" />
     <SolidColorBrush x:Key="SystemControlHighlightChromeWhiteBrush" Color="{m:StaticColor SystemChromeWhiteColor}" />
@@ -685,9 +687,9 @@
     <m:StaticResource x:Key="ListViewItemBackground" ResourceKey="SystemControlTransparentBrush" />
     <m:StaticResource x:Key="ListViewItemBackgroundPointerOver" ResourceKey="SystemControlHighlightListLowBrush" />
     <m:StaticResource x:Key="ListViewItemBackgroundPressed" ResourceKey="SystemControlHighlightListMediumBrush" />
-    <m:StaticResource x:Key="ListViewItemBackgroundSelected" ResourceKey="SystemControlHighlightListAccentLowBrush" />
-    <m:StaticResource x:Key="ListViewItemBackgroundSelectedPointerOver" ResourceKey="SystemControlHighlightListAccentMediumBrush" />
-    <m:StaticResource x:Key="ListViewItemBackgroundSelectedPressed" ResourceKey="SystemControlHighlightListAccentHighBrush" />
+    <m:StaticResource x:Key="ListViewItemBackgroundSelected" ResourceKey="SystemControlHighlightListAccentMediumLowBrush" />
+    <m:StaticResource x:Key="ListViewItemBackgroundSelectedPointerOver" ResourceKey="SystemControlHighlightListAccentLowBrush" />
+    <m:StaticResource x:Key="ListViewItemBackgroundSelectedPressed" ResourceKey="SystemControlHighlightListAccentVeryHighBrush" />
     <m:StaticResource x:Key="ListViewItemForeground" ResourceKey="SystemControlForegroundBaseHighBrush" />
     <m:StaticResource x:Key="ListViewItemForegroundPointerOver" ResourceKey="SystemControlHighlightAltBaseHighBrush" />
     <m:StaticResource x:Key="ListViewItemForegroundSelected" ResourceKey="SystemControlHighlightAltBaseHighBrush" />

ModernWpf/ThemeResources/HighContrast.xaml

@@ -120,6 +120,8 @@
     <SolidColorBrush x:Key="SystemControlHighlightListAccentHighBrush" Color="{m:ThemeResource SystemColorHighlightColor}" />
     <SolidColorBrush x:Key="SystemControlHighlightListAccentLowBrush" Color="{m:ThemeResource SystemColorHighlightColor}" />
     <SolidColorBrush x:Key="SystemControlHighlightListAccentMediumBrush" Color="{m:ThemeResource SystemColorHighlightColor}" />
+    <SolidColorBrush x:Key="SystemControlHighlightListAccentVeryHighBrush" Color="{m:ThemeResource SystemColorHighlightColor}" />
+    <SolidColorBrush x:Key="SystemControlHighlightListAccentMediumLowBrush" Color="{m:ThemeResource SystemColorHighlightColor}" />
     <SolidColorBrush x:Key="SystemControlHighlightListMediumBrush" Color="{m:ThemeResource SystemColorHighlightColor}" />
     <SolidColorBrush x:Key="SystemControlHighlightListLowBrush" Color="{m:ThemeResource SystemColorHighlightColor}" />
     <SolidColorBrush x:Key="SystemControlHighlightChromeWhiteBrush" Color="{m:ThemeResource SystemColorHighlightColor}" />
@@ -685,9 +687,9 @@
     <m:StaticResource x:Key="ListViewItemBackground" ResourceKey="SystemControlTransparentBrush" />
     <m:StaticResource x:Key="ListViewItemBackgroundPointerOver" ResourceKey="SystemControlHighlightListLowBrush" />
     <m:StaticResource x:Key="ListViewItemBackgroundPressed" ResourceKey="SystemControlHighlightListMediumBrush" />
-    <m:StaticResource x:Key="ListViewItemBackgroundSelected" ResourceKey="SystemControlHighlightListAccentLowBrush" />
+    <m:StaticResource x:Key="ListViewItemBackgroundSelected" ResourceKey="SystemControlHighlightListAccentMediumLowBrush" />
     <m:StaticResource x:Key="ListViewItemBackgroundSelectedPointerOver" ResourceKey="SystemControlHighlightListAccentMediumBrush" />
-    <m:StaticResource x:Key="ListViewItemBackgroundSelectedPressed" ResourceKey="SystemControlHighlightListAccentHighBrush" />
+    <m:StaticResource x:Key="ListViewItemBackgroundSelectedPressed" ResourceKey="SystemControlHighlightListAccentVeryHighBrush" />
     <m:StaticResource x:Key="ListViewItemForeground" ResourceKey="SystemControlForegroundBaseHighBrush" />
     <m:StaticResource x:Key="ListViewItemForegroundPointerOver" ResourceKey="SystemControlHighlightAltBaseHighBrush" />
     <m:StaticResource x:Key="ListViewItemForegroundSelected" ResourceKey="SystemControlHighlightAltBaseHighBrush" />

ModernWpf/ThemeResources/Light.xaml

@@ -120,6 +120,8 @@
     <SolidColorBrush x:Key="SystemControlHighlightListAccentHighBrush" Color="{m:DynamicColor SystemAccentColor}" Opacity="0.7" />
     <SolidColorBrush x:Key="SystemControlHighlightListAccentLowBrush" Color="{m:DynamicColor SystemAccentColor}" Opacity="0.4" />
     <SolidColorBrush x:Key="SystemControlHighlightListAccentMediumBrush" Color="{m:DynamicColor SystemAccentColor}" Opacity="0.6" />
+    <SolidColorBrush x:Key="SystemControlHighlightListAccentVeryHighBrush" Color="{m:DynamicColor SystemAccentColor}" Opacity="0.9" />
+    <SolidColorBrush x:Key="SystemControlHighlightListAccentMediumLowBrush" Color="{m:DynamicColor SystemAccentColor}" Opacity="0.75" />
     <SolidColorBrush x:Key="SystemControlHighlightListMediumBrush" Color="{m:StaticColor SystemListMediumColor}" />
     <SolidColorBrush x:Key="SystemControlHighlightListLowBrush" Color="{m:StaticColor SystemListLowColor}" />
     <SolidColorBrush x:Key="SystemControlHighlightChromeWhiteBrush" Color="{m:StaticColor SystemChromeWhiteColor}" />
@@ -685,9 +687,9 @@
     <m:StaticResource x:Key="ListViewItemBackground" ResourceKey="SystemControlTransparentBrush" />
     <m:StaticResource x:Key="ListViewItemBackgroundPointerOver" ResourceKey="SystemControlHighlightListLowBrush" />
     <m:StaticResource x:Key="ListViewItemBackgroundPressed" ResourceKey="SystemControlHighlightListMediumBrush" />
-    <m:StaticResource x:Key="ListViewItemBackgroundSelected" ResourceKey="SystemControlHighlightListAccentLowBrush" />
+    <m:StaticResource x:Key="ListViewItemBackgroundSelected" ResourceKey="SystemControlHighlightListAccentMediumLowBrush" />
     <m:StaticResource x:Key="ListViewItemBackgroundSelectedPointerOver" ResourceKey="SystemControlHighlightListAccentMediumBrush" />
-    <m:StaticResource x:Key="ListViewItemBackgroundSelectedPressed" ResourceKey="SystemControlHighlightListAccentHighBrush" />
+    <m:StaticResource x:Key="ListViewItemBackgroundSelectedPressed" ResourceKey="SystemControlHighlightListAccentVeryHighBrush" />
     <m:StaticResource x:Key="ListViewItemForeground" ResourceKey="SystemControlForegroundBaseHighBrush" />
     <m:StaticResource x:Key="ListViewItemForegroundPointerOver" ResourceKey="SystemControlHighlightAltBaseHighBrush" />
     <m:StaticResource x:Key="ListViewItemForegroundSelected" ResourceKey="SystemControlHighlightAltBaseHighBrush" />