Theme: dark ComboBox dropdown popups and items

Author: dooly123

src/BasisPM.App/Styles/BasisTheme.axaml

@@ -43,6 +43,9 @@
             <SolidColorBrush x:Key="BasisBorderStrongBrush" Color="{StaticResource BasisBorderStrong}"/>
             <SolidColorBrush x:Key="BasisGlassBrush" Color="{StaticResource BasisGlass}"/>
             <SolidColorBrush x:Key="BasisGlassStrongBrush" Color="{StaticResource BasisGlassStrong}"/>
+            <!-- Override the Fluent ComboBox dropdown-popup fill to the dark scheme (backup for the
+                 ComboBox /template/ Border#PopupBorder selector); Fluent's default is light/translucent. -->
+            <SolidColorBrush x:Key="ComboBoxDropDownBackground" Color="{StaticResource BasisSurface}"/>
             <SolidColorBrush x:Key="BasisTextPrimaryBrush" Color="{StaticResource BasisTextPrimary}"/>
             <SolidColorBrush x:Key="BasisTextMutedBrush" Color="{StaticResource BasisTextMuted}"/>
             <SolidColorBrush x:Key="BasisTextSecondaryBrush" Color="{StaticResource BasisTextSecondary}"/>
@@ -344,6 +347,26 @@
         <Setter Property="Background" Value="Transparent"/>
         <Setter Property="Padding" Value="12,8"/>
     </Style>
+    <!-- Dropdown popup + item states: match the dark scheme. Fluent's defaults are a light/
+         translucent popup and a blue accent highlight, which don't match the Basis palette. -->
+    <Style Selector="ComboBox /template/ Border#PopupBorder">
+        <Setter Property="Background" Value="{StaticResource BasisSurfaceBrush}"/>
+        <Setter Property="BorderBrush" Value="{StaticResource BasisBorderStrongBrush}"/>
+        <Setter Property="BorderThickness" Value="1"/>
+        <Setter Property="CornerRadius" Value="10"/>
+    </Style>
+    <Style Selector="ComboBoxItem:pointerover /template/ ContentPresenter#PART_ContentPresenter">
+        <Setter Property="Background" Value="{StaticResource BasisSurfaceHoverBrush}"/>
+        <Setter Property="TextElement.Foreground" Value="{StaticResource BasisTextPrimaryBrush}"/>
+    </Style>
+    <Style Selector="ComboBoxItem:selected /template/ ContentPresenter#PART_ContentPresenter">
+        <Setter Property="Background" Value="{StaticResource BasisSurfaceHoverBrush}"/>
+        <Setter Property="TextElement.Foreground" Value="{StaticResource BasisTextPrimaryBrush}"/>
+    </Style>
+    <Style Selector="ComboBoxItem:selected:pointerover /template/ ContentPresenter#PART_ContentPresenter">
+        <Setter Property="Background" Value="{StaticResource BasisSurfaceHoverBrush}"/>
+        <Setter Property="TextElement.Foreground" Value="{StaticResource BasisTextPrimaryBrush}"/>
+    </Style>
 
     <Style Selector="CheckBox">
         <Setter Property="Foreground" Value="{StaticResource BasisTextPrimaryBrush}"/>