diff --git a/src/AdvancedCalculator/Styles/Colors.axaml b/src/AdvancedCalculator/Styles/Colors.axaml
index 24438bd..3dd99b2 100644
--- a/src/AdvancedCalculator/Styles/Colors.axaml
+++ b/src/AdvancedCalculator/Styles/Colors.axaml
@@ -1,6 +1,9 @@
 <Styles xmlns="https://github.com/avaloniaui"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
   <Styles.Resources>
+    <!-- Base surface + foreground colors as Color resources to allow reuse -->
+    <Color x:Key="CSurface">#FFF0F4F7</Color>
+    <Color x:Key="CForeground">#FF0F1A21</Color>
     <!-- Core palette -->
     <Color x:Key="CPrimary1">#FF5AC3D6</Color>
     <Color x:Key="CPrimary2">#FF223544</Color>
@@ -18,9 +21,9 @@
     <SolidColorBrush x:Key="Brush.Emph3" Color="{DynamicResource CEmph3}"/>
 
     <!-- Derived brushes for surfaces and text -->
-    <SolidColorBrush x:Key="Brush.Surface">#F0F4F7</SolidColorBrush>
+    <SolidColorBrush x:Key="Brush.Surface" Color="{DynamicResource CSurface}"/>
     <SolidColorBrush x:Key="Brush.SurfaceAlt" Color="{DynamicResource CPrimary3}" Opacity="0.10"/>
-    <SolidColorBrush x:Key="Brush.Foreground">#FF0F1A21</SolidColorBrush>
+    <SolidColorBrush x:Key="Brush.Foreground" Color="{DynamicResource CForeground}"/>
     <SolidColorBrush x:Key="Brush.ForegroundOnPrimary">#FFFFFFFF</SolidColorBrush>
 
     <!-- Utility tints -->
@@ -30,8 +33,8 @@
 
     <!-- Accent + theme integration (FluentTheme consumes these) -->
     <SolidColorBrush x:Key="ThemeAccentBrush" Color="{DynamicResource CPrimary1}"/>
-    <SolidColorBrush x:Key="ThemeBackgroundBrush" Color="{DynamicResource Brush.Surface.Color}"/>
-    <SolidColorBrush x:Key="ThemeForegroundBrush" Color="{DynamicResource Brush.Foreground.Color}"/>
+    <SolidColorBrush x:Key="ThemeBackgroundBrush" Color="{DynamicResource CSurface}"/>
+    <SolidColorBrush x:Key="ThemeForegroundBrush" Color="{DynamicResource CForeground}"/>
   </Styles.Resources>
 
   <!-- Window background -->
@@ -115,7 +118,7 @@
     <Setter Property="BorderBrush" Value="{DynamicResource ThemeAccentBrush}"/>
   </Style>
   <Style Selector="ListBox">
-    <Setter Property="Background" Value="Transparent"/>
+    <Setter Property="Background" Value="{DynamicResource Brush.Surface}"/>
   </Style>
 
   <!-- Menus & flyouts -->