<Style x:Key="{x:Type ComboBoxItem}" TargetType="{x:Type ComboBoxItem}">
    <Setter Property="SnapsToDevicePixels" Value="true" />
    <Setter Property="OverridesDefaultStyle" Value="true" />
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type ComboBoxItem}">
                <Border x:Name="Border"
                        Padding="2"
                        SnapsToDevicePixels="true">
                    <Border.Style>
                        <Style TargetType="{x:Type Border}">
                            <Style.Triggers>
                                <Trigger Property="IsMouseOver" Value="True">
                                    <Trigger.EnterActions>
                                        <BeginStoryboard>
                                            <Storyboard>
                                                <ColorAnimation Duration="0:0:0.01"
                                                                Storyboard.TargetProperty="(Panel.Background).(SolidColorBrush.Color)"
                                                                To="#FFA7ACD4" />
                                            </Storyboard>
                                        </BeginStoryboard>
                                    </Trigger.EnterActions>
                                    <Trigger.ExitActions>
                                        <BeginStoryboard>
                                            <Storyboard>
                                                <ColorAnimation Duration="0:0:0.6"
                                                                Storyboard.TargetProperty="(Panel.Background).(SolidColorBrush.Color)"
                                                                To="White" />
                                            </Storyboard>
                                        </BeginStoryboard>
                                    </Trigger.ExitActions>
                                </Trigger>
                            </Style.Triggers>
                        </Style>
                    </Border.Style>
                    <VisualStateManager.VisualStateGroups>
                        <VisualStateGroup x:Name="SelectionStates">
                            <VisualState x:Name="Unselected" />
                            <VisualState x:Name="Selected">
                                <Storyboard>
                                    <ColorAnimationUsingKeyFrames Storyboard.TargetName="Border"
                                              Storyboard.TargetProperty="(Panel.Background).(SolidColorBrush.Color)">
                                        <EasingColorKeyFrame KeyTime="0" Value="{DynamicResource ColorItemSelectedBackground}" />
                                    </ColorAnimationUsingKeyFrames>
                                </Storyboard>
                            </VisualState>
                            <VisualState x:Name="SelectedUnfocused">
                                <Storyboard>
                                    <ColorAnimationUsingKeyFrames Storyboard.TargetName="Border"
                                            Storyboard.TargetProperty="(Panel.Background).(SolidColorBrush.Color)">
                                        <EasingColorKeyFrame KeyTime="0"
                                            Value="{StaticResource SelectedUnfocusedColor}" />
                                    </ColorAnimationUsingKeyFrames>
                                </Storyboard>
                            </VisualState>
                        </VisualStateGroup>
                    </VisualStateManager.VisualStateGroups>
                    <ContentPresenter />
                </Border>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>