Drop down style in WPF

<SolidColorBrush x:Key="ComboBoxNormalBorderBrush" Color="#071c2c" />

    <SolidColorBrush x:Key="ComboBoxNormalBackgroundBrush" Color="#fff" />

    <SolidColorBrush x:Key="ComboBoxNormalBackgroundBrushArrow" Color="#071c2c" />

    <SolidColorBrush x:Key="ComboBoxDisabledForegroundBrush" Color="#888" />

    <SolidColorBrush x:Key="ComboBoxDisabledBackgroundBrush" Color="#eee" />

    <SolidColorBrush x:Key="ComboBoxDisabledBorderBrush" Color="#888" />

    <ControlTemplate TargetType="ToggleButton" x:Key="ComboBoxToggleButtonTemplate">

        <Grid>

            <Grid.ColumnDefinitions>

                <ColumnDefinition />

                <ColumnDefinition Width="26" />

            </Grid.ColumnDefinitions>

            <Border Grid.ColumnSpan="2" Name="Border"

              BorderBrush="{StaticResource ComboBoxNormalBorderBrush}"

              CornerRadius="0" BorderThickness="1, 1, 1, 1"

              Background="{StaticResource ComboBoxNormalBackgroundBrush}" />

            <Border Grid.Column="1" Margin="1, 1, 1, 1" BorderBrush="#444" Name="ButtonBorder"

              CornerRadius="0, 0, 0, 0" BorderThickness="0, 0, 0, 0"

              Background="{StaticResource ComboBoxNormalBackgroundBrushArrow}" />

            <Path Name="Arrow" Grid.Column="1"

            Data="M0,0 L0,2 L4,6 L8,2 L8,0 L4,4 z"

            HorizontalAlignment="Center" Fill="White"

            VerticalAlignment="Center" />

        </Grid>

        <ControlTemplate.Triggers>

            <Trigger Property="UIElement.IsMouseOver" Value="True">

                <Setter Property="Panel.Background" TargetName="ButtonBorder" Value="White"/>

                <Setter Property="Shape.Fill" TargetName="Arrow" Value="#071c2c"/>

             

            </Trigger>

            <Trigger Property="ToggleButton.IsChecked" Value="True">

                <Setter Property="Panel.Background" TargetName="ButtonBorder" Value="#071c2c"/>

                <Setter Property="Shape.Fill" TargetName="Arrow" Value="White"/>

            </Trigger>

            <Trigger Property="UIElement.IsEnabled" Value="False">

                <Setter Property="Panel.Background" TargetName="Border" Value="{StaticResource ComboBoxDisabledBackgroundBrush}"/>

                <Setter Property="Panel.Background" TargetName="ButtonBorder" Value="{StaticResource ComboBoxDisabledBackgroundBrush}"/>

                <Setter Property="Border.BorderBrush" TargetName="ButtonBorder" Value="{StaticResource ComboBoxDisabledBorderBrush}"/>

                <Setter Property="TextElement.Foreground" Value="{StaticResource ComboBoxDisabledForegroundBrush}"/>

                <Setter Property="Shape.Fill" TargetName="Arrow" Value="#999"/>

            </Trigger>

        </ControlTemplate.Triggers>

    </ControlTemplate>

    <Style  TargetType="{x:Type ComboBox}">

        <Setter Property="UIElement.SnapsToDevicePixels" Value="True"/>

        <Setter Property="FrameworkElement.OverridesDefaultStyle" Value="True"/>

        <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto"/>

        <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto"/>

        <Setter Property="ScrollViewer.CanContentScroll" Value="True"/>

        <Setter Property="TextElement.Foreground" Value="#071c2c"/>

        <Setter Property="FrameworkElement.FocusVisualStyle" Value="{x:Null}"/>

        <Setter Property="FontFamily" Value="Arial-BoldMT"></Setter>

        <Setter Property="FontSize" Value="30"></Setter>

        <Setter Property="FontWeight" Value="SemiBold"></Setter>

    

        <Setter Property="Control.Template">

            <Setter.Value>

                <ControlTemplate TargetType="ComboBox">

                    <Grid>

                        <ToggleButton Name="ToggleButton" Grid.Column="2"

                ClickMode="Press" Focusable="False"

                IsChecked="{Binding Path=IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}, Mode=TwoWay}"

                Template="{StaticResource ComboBoxToggleButtonTemplate}"/>

                        <ContentPresenter Name="ContentSite" Margin="5, 3, 23, 3" IsHitTestVisible="False"

                              HorizontalAlignment="Left" VerticalAlignment="Center"                             

                              Content="{TemplateBinding ComboBox.SelectionBoxItem}"

                              ContentTemplate="{TemplateBinding ComboBox.SelectionBoxItemTemplate}"

                              ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}"/>

                       

                        <TextBox Name="PART_EditableTextBox" Margin="3, 3, 23, 3"                    

                     IsReadOnly="{TemplateBinding IsReadOnly}"

                     Visibility="Hidden" Background="Transparent"

                     HorizontalAlignment="Left" VerticalAlignment="Center"

                     Focusable="True" >

                            <TextBox.Template>

                                <ControlTemplate TargetType="TextBox" >

                                    <Border Name="PART_ContentHost" Focusable="False" />

                                </ControlTemplate>

                            </TextBox.Template>

                        </TextBox>

                        <!-- Popup showing items -->

                        <Popup Name="Popup" Placement="Bottom"

                   Focusable="False" AllowsTransparency="True"

                   IsOpen="{TemplateBinding ComboBox.IsDropDownOpen}"

                   PopupAnimation="Slide">

                            <Grid Name="DropDown" SnapsToDevicePixels="True"

                    MinWidth="{TemplateBinding FrameworkElement.ActualWidth}"

                    MaxHeight="{TemplateBinding ComboBox.MaxDropDownHeight}">

                                <Border Name="DropDownBorder" Background="White" Margin="0, 1, 0, 0"

                        CornerRadius="0" BorderThickness="1,1,1,1"

                        BorderBrush="{StaticResource ComboBoxNormalBorderBrush}"/>

                                <ScrollViewer Margin="4" SnapsToDevicePixels="True">

                                    <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" />

                                </ScrollViewer>

                            </Grid>

                        </Popup>

                    </Grid>

                    <ControlTemplate.Triggers>

                        <Trigger Property="ItemsControl.HasItems" Value="False">

                            <Setter Property="FrameworkElement.MinHeight" TargetName="DropDownBorder" Value="95"/>

                        </Trigger>

                        <Trigger Property="UIElement.IsEnabled" Value="False">

                            <Setter Property="TextElement.Foreground" Value="{StaticResource ComboBoxDisabledForegroundBrush}"/>

                        </Trigger>

                        <Trigger Property="ItemsControl.IsGrouping" Value="True">

                            <Setter Property="ScrollViewer.CanContentScroll" Value="False"/>

                        </Trigger>

                        <Trigger Property="ComboBox.IsEditable" Value="True">

                            <Setter Property="KeyboardNavigation.IsTabStop" Value="False"/>

                            <Setter Property="UIElement.Visibility" TargetName="PART_EditableTextBox" Value="Visible"/>

                            <Setter Property="UIElement.Visibility" TargetName="ContentSite" Value="Hidden"/>

                        </Trigger>

                    </ControlTemplate.Triggers>

                </ControlTemplate>

            </Setter.Value>

        </Setter>

    </Style>

    <!-- End of Flat ComboBox -->