想给这段代码生成的按钮添加个按压时按钮改变颜色的效果 哪位大神帮助一下？

 <Window.Resources>
        <Style x:Key="ButtonStyle1" TargetType="{x:Type Button}">
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type Button}">
                        <Grid>
                            <Ellipse RenderTransformOrigin="0.5,0.5" Stroke="#FFD8A924" StrokeThickness="5">
                                <Ellipse.Fill>
                                    <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
                                        <GradientStop Color="#FFF3CB12" Offset="0"/>
                                        <GradientStop Color="#FFFBB065" Offset="1"/>
                                        <GradientStop Color="#FFE5CA4B" Offset="0.552"/>
                                    </LinearGradientBrush>
                                </Ellipse.Fill>
                                <Ellipse.RenderTransform>
                                    <TransformGroup>
                                        <ScaleTransform/>
                                        <SkewTransform/>
                                        <RotateTransform Angle="-90.332"/>
                                        <TranslateTransform/>
                                    </TransformGroup>
                                </Ellipse.RenderTransform>
                            </Ellipse>
                            <ContentPresenter HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" RecognizesAccessKey="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" Content="更正"/>   
                        </Grid>
                        <ControlTemplate.Triggers>
                            <Trigger Property="IsFocused" Value="True"/>
                            <Trigger Property="IsDefaulted" Value="True"/>
                            <Trigger Property="IsMouseOver" Value="True">

                                </Trigger>
                            <Trigger Property="IsPressed" Value="True">

                           </Trigger>
                            <Trigger Property="IsEnabled" Value="False"/>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </Window.Resources>

添加一个按下按钮的事件，在事件里改变按钮颜色