diff --git a/src/Semi.Avalonia/Controls/ComboBox.axaml b/src/Semi.Avalonia/Controls/ComboBox.axaml
index 2a8fc6e..760380a 100644
--- a/src/Semi.Avalonia/Controls/ComboBox.axaml
+++ b/src/Semi.Avalonia/Controls/ComboBox.axaml
@@ -30,11 +30,11 @@
     <ControlTheme x:Key="{x:Type ComboBox}" TargetType="ComboBox">
         <Setter Property="Padding" Value="{DynamicResource ComboBoxSelectorDefaultPadding}" />
         <Setter Property="FocusAdorner" Value="{x:Null}" />
-        <Setter Property="MaxDropDownHeight" Value="504" />
+        <Setter Property="MaxDropDownHeight" Value="{DynamicResource ComboBoxPopupMaxDropDownHeight}" />
         <Setter Property="Background" Value="{DynamicResource ComboBoxSelectorBackground}" />
         <Setter Property="BorderBrush" Value="{DynamicResource ComboBoxSelectorBorderBrush}" />
         <Setter Property="BackgroundSizing" Value="OuterBorderEdge" />
-        <Setter Property="BorderThickness" Value="1" />
+        <Setter Property="BorderThickness" Value="{DynamicResource ComboBoxSelectorThickness}" />
         <Setter Property="Cursor" Value="Hand" />
         <Setter Property="CornerRadius" Value="{DynamicResource ComboBoxSelectorCornerRadius}" />
         <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Disabled" />
@@ -80,27 +80,19 @@
                         <Button
                             Name="ClearButton"
                             Grid.Column="1"
-                            Margin="0,0,8,0"
+                            Margin="{DynamicResource ComboBoxClearButtonMargin}"
                             Command="{Binding $parent[ComboBox].Clear}"
                             Content="{DynamicResource IconButtonClearData}"
                             Focusable="False"
                             IsVisible="False"
                             Theme="{DynamicResource InnerIconButton}" />
-                        <Border
-                            Name="DropDownOverlay"
-                            Grid.Column="1"
-                            Width="30"
-                            Margin="0,1,1,1"
-                            HorizontalAlignment="Right"
-                            Background="Transparent"
-                            IsVisible="False" />
 
                         <PathIcon
                             Name="DropDownGlyph"
                             Grid.Column="1"
-                            Width="12"
-                            Height="12"
-                            Margin="0,0,12,0"
+                            Width="{DynamicResource ComboBoxIconWidth}"
+                            Height="{DynamicResource ComboBoxIconHeight}"
+                            Margin="{DynamicResource ComboBoxIconMargin}"
                             Data="{DynamicResource ComboBoxIcon}"
                             Foreground="{DynamicResource ComboBoxIconDefaultForeground}"
                             IsHitTestVisible="False"
@@ -119,14 +111,14 @@
                             WindowManagerAddShadowHint="False">
                             <Border
                                 Name="PopupBorder"
-                                Margin="0,4"
                                 HorizontalAlignment="Stretch"
+                                Margin="{DynamicResource ComboBoxPopupBorderMargin}"
                                 Background="{DynamicResource ComboBoxPopupBackground}"
                                 BorderBrush="{DynamicResource ComboBoxPopupBorderBrush}"
                                 BorderThickness="{DynamicResource ComboBoxPopupBorderThickness}"
                                 BoxShadow="{DynamicResource ComboBoxPopupBoxShadow}"
-                                ClipToBounds="True"
-                                CornerRadius="6">
+                                CornerRadius="{DynamicResource ComboBoxPopupBoxCornerRadius}"
+                                ClipToBounds="True">
                                 <ScrollViewer
                                     HorizontalScrollBarVisibility="{TemplateBinding ScrollViewer.HorizontalScrollBarVisibility}"
                                     IsDeferredScrollingEnabled="{TemplateBinding ScrollViewer.IsDeferredScrollingEnabled}"
diff --git a/src/Semi.Avalonia/Themes/Shared/ComboBox.axaml b/src/Semi.Avalonia/Themes/Shared/ComboBox.axaml
index 7f0b531..2930b5f 100644
--- a/src/Semi.Avalonia/Themes/Shared/ComboBox.axaml
+++ b/src/Semi.Avalonia/Themes/Shared/ComboBox.axaml
@@ -1,14 +1,22 @@
 <ResourceDictionary xmlns="https://github.com/avaloniaui" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
     <CornerRadius x:Key="ComboBoxSelectorCornerRadius">3</CornerRadius>
+    <Thickness x:Key="ComboBoxSelectorThickness">1</Thickness>
 
     <Thickness x:Key="ComboBoxItemDefaultPadding">12 8</Thickness>
     <Thickness x:Key="ComboBoxSelectorDefaultPadding">8 0</Thickness>
 
+    <x:Double x:Key="ComboBoxPopupMaxDropDownHeight">504</x:Double>
     <Thickness x:Key="ComboBoxPopupBorderThickness">1</Thickness>
+    <CornerRadius x:Key="ComboBoxPopupBoxCornerRadius">6</CornerRadius>
 
+    <Thickness x:Key="ComboBoxClearButtonMargin">0 0 8 0</Thickness>
+    <Thickness x:Key="ComboBoxIconMargin">0 0 12 0</Thickness>
+    <x:Double x:Key="ComboBoxIconWidth">12</x:Double>
+    <x:Double x:Key="ComboBoxIconHeight">12</x:Double>
     <StreamGeometry x:Key="ComboBoxIcon">
         M4.08045 7.59809C4.66624 7.01231 5.61599 7.01231 6.20177 7.59809L11.8586 13.2549L17.5155 7.59809C18.1013 7.01231 19.051 7.01231 19.6368 7.59809C20.2226 8.18388 20.2226 9.13363 19.6368 9.71941L12.9193 16.4369C12.3335 17.0227 11.3838 17.0227 10.798 16.4369L4.08045 9.71941C3.49467 9.13363 3.49467 8.18388 4.08045 7.59809Z
     </StreamGeometry>
+    <Thickness x:Key="ComboBoxPopupBorderMargin">0 4</Thickness>
 
     <x:Double x:Key="ComboBoxDefaultHeight">32</x:Double>
     <x:Double x:Key="ComboBoxSmallHeight">24</x:Double>