diff --git a/README.md b/README.md
index 4e7f87b3..d84335ed 100644
--- a/README.md
+++ b/README.md
@@ -111,8 +111,6 @@ This app supports open repository in external tools listed in the table below.
 | Color.Border2 | Border color used in visual lines, like seperators, Rectange, etc. |
 | Color.FlatButton.Background | Flat button background color, like `Cancel`, `Commit & Push` button |
 | Color.FlatButton.BackgroundHovered | Flat button background color when hovered, like `Cancel` button |
-| Color.FlatButton.PrimaryBackground | Primary flat button background color, like `Ok`, `Commit` button |
-| Color.FlatButton.PrimaryBackgroundHovered | Primary flat button background color when hovered, like `Ok`, `Commit` button |
 | Color.FG1 | Primary foreground color for all text elements |
 | Color.FG2 | Secondary foreground color for all text elements |
 | Color.Diff.EmptyBG | Background color used in empty lines in diff viewer |
diff --git a/src/Resources/Styles.axaml b/src/Resources/Styles.axaml
index fdf3ec3e..ca15f55f 100644
--- a/src/Resources/Styles.axaml
+++ b/src/Resources/Styles.axaml
@@ -405,7 +405,8 @@
   </Style>
 
   <Style Selector="Button.flat">
-    <Setter Property="BorderThickness" Value="0"/>
+    <Setter Property="BorderThickness" Value="1"/>
+    <Setter Property="BorderBrush" Value="{DynamicResource Brush.Border2}"/>
     <Setter Property="FontWeight" Value="Bold"/>
     <Setter Property="TextBlock.TextAlignment" Value="Center"/>
     <Setter Property="Foreground" Value="{DynamicResource Brush.FG1}"/>
@@ -419,8 +420,7 @@
                   Background="{TemplateBinding Background}"
                   BorderBrush="{TemplateBinding BorderBrush}"
                   BorderThickness="{TemplateBinding BorderThickness}"
-                  CornerRadius="{TemplateBinding CornerRadius}"
-                  Effect="drop-shadow(0 0 2 #80000000)"/>
+                  CornerRadius="{TemplateBinding CornerRadius}"/>
 
           <ContentPresenter x:Name="PART_ContentPresenter"
                             Margin="2"
@@ -441,10 +441,11 @@
     <Setter Property="Background" Value="Transparent"/>
   </Style>
   <Style Selector="Button.flat.primary">
-    <Setter Property="Background" Value="{DynamicResource Brush.FlatButton.PrimaryBackground}"/>
+    <Setter Property="BorderBrush" Value="{DynamicResource AccentButtonBorderBrush}"/>
+    <Setter Property="Background" Value="{DynamicResource AccentButtonBackground}"/>
   </Style>
   <Style Selector="Button.flat.primary:pointerover /template/ Border#PART_Border">
-    <Setter Property="Background" Value="{DynamicResource Brush.FlatButton.PrimaryBackgroundHovered}"/>
+    <Setter Property="Background" Value="{DynamicResource AccentButtonBackgroundPointerOver}"/>
   </Style>
   <Style Selector="Button.flat.primary:pointerover /template/ ContentPresenter#PART_ContentPresenter">
     <Setter Property="Background" Value="Transparent"/>
diff --git a/src/Resources/Themes.axaml b/src/Resources/Themes.axaml
index 40ff7ca6..c322ba5a 100644
--- a/src/Resources/Themes.axaml
+++ b/src/Resources/Themes.axaml
@@ -21,8 +21,6 @@
       <Color x:Key="Color.Border2">#FFCFCFCF</Color>
       <Color x:Key="Color.FlatButton.Background">#FFF8F8F8</Color>
       <Color x:Key="Color.FlatButton.BackgroundHovered">White</Color>
-      <Color x:Key="Color.FlatButton.PrimaryBackground">#FF4295FF</Color>
-      <Color x:Key="Color.FlatButton.PrimaryBackgroundHovered">#FF529DFB</Color>
       <Color x:Key="Color.FG1">#FF1F1F1F</Color>
       <Color x:Key="Color.FG2">#FF6F6F6F</Color>
       <Color x:Key="Color.Diff.EmptyBG">#3C000000</Color>
@@ -52,8 +50,6 @@
       <Color x:Key="Color.Border2">#FF404040</Color>
       <Color x:Key="Color.FlatButton.Background">#FF303030</Color>
       <Color x:Key="Color.FlatButton.BackgroundHovered">#FF333333</Color>
-      <Color x:Key="Color.FlatButton.PrimaryBackground">#FF3A3A3A</Color>
-      <Color x:Key="Color.FlatButton.PrimaryBackgroundHovered">#FF404040</Color>
       <Color x:Key="Color.FG1">#FFDDDDDD</Color>
       <Color x:Key="Color.FG2">#40F1F1F1</Color>
       <Color x:Key="Color.Diff.EmptyBG">#3C000000</Color>
@@ -83,8 +79,6 @@
   <SolidColorBrush x:Key="Brush.Border2" Color="{DynamicResource Color.Border2}"/>
   <SolidColorBrush x:Key="Brush.FlatButton.Background" Color="{DynamicResource Color.FlatButton.Background}"/>
   <SolidColorBrush x:Key="Brush.FlatButton.BackgroundHovered" Color="{DynamicResource Color.FlatButton.BackgroundHovered}"/>
-  <SolidColorBrush x:Key="Brush.FlatButton.PrimaryBackground" Color="{DynamicResource Color.FlatButton.PrimaryBackground}"/>
-  <SolidColorBrush x:Key="Brush.FlatButton.PrimaryBackgroundHovered" Color="{DynamicResource Color.FlatButton.PrimaryBackgroundHovered}"/>
   <SolidColorBrush x:Key="Brush.FG1" Color="{DynamicResource Color.FG1}"/>
   <SolidColorBrush x:Key="Brush.FG2" Color="{DynamicResource Color.FG2}"/>
   <SolidColorBrush x:Key="Brush.Accent" Color="{DynamicResource SystemAccentColor}"/>