basestyle.xaml

        <Style x:Key="BaseButtonStyle" TargetType="{x:Type Button}" BasedOn="{x:Null}">
            <Setter Property="Foreground" Value="{StaticResource ButtonFontColor}"/>
            <Setter Property="Padding" Value="3"/>
            <Setter Property="FocusVisualStyle" Value="{DynamicResource NuclearButtonFocusVisual}"/>
            <Setter Property="Template" Value="{DynamicResource ButtonTemplate}" />
        </Style>

    <Style TargetType="{x:Type Button}" BasedOn="{StaticResource BaseButtonStyle}" />

    <ControlTemplate x:Key="ButtonTemplate" TargetType="{x:Type Button}">
                        <ControlTemplate.Resources>
                            <Storyboard x:Key="PressedOn">
                                <DoubleAnimation Duration="00:00:00.1000000" Storyboard.TargetName="BackgroundPressed" Storyboard.TargetProperty="Opacity" To="0.84"/>
                                <DoubleAnimation Duration="00:00:00.1000000" Storyboard.TargetName="BackgoundPressed_Highlight" Storyboard.TargetProperty="Opacity" To="0.65"/>
                            </Storyboard>
                            <Storyboard x:Key="PressedOff">
                                <DoubleAnimation Duration="00:00:00.4000000" Storyboard.TargetName="BackgroundPressed" Storyboard.TargetProperty="Opacity" To="0"/>
                                <DoubleAnimation Duration="00:00:00.4000000" Storyboard.TargetName="BackgoundPressed_Highlight" Storyboard.TargetProperty="Opacity" To="0"/>
                            </Storyboard>
                        </ControlTemplate.Resources>
                        <Grid x:Name="Grid">
                            <Border x:Name="BackgroundPressed" Background="{StaticResource BtnPressFill}" BorderBrush="{StaticResource btnPressBorder}" BorderThickness="1" CornerRadius="3" Opacity="0"/>
                            <Border x:Name="BackgoundPressed_Highlight" Background="{StaticResource btnPressFillHighlight}" Margin="1" CornerRadius="2.5" Opacity="0"/>
                        </Grid>

                        <ControlTemplate.Triggers>
                            <Trigger Property="IsDefault" Value="True">
                                <Setter Property="Opacity" TargetName="DefaultBorder" Value="1"/>
                            </Trigger>
                            <Trigger Property="IsPressed" Value="true">
                                <Trigger.ExitActions>
                                    <BeginStoryboard Storyboard="{StaticResource PressedOff}" />
                                </Trigger.ExitActions>
                                <Trigger.EnterActions>
                                    <BeginStoryboard Storyboard="{StaticResource PressedOn}"/>
                                </Trigger.EnterActions>
                            </Trigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>

style.xaml

    <Style TargetType="classes:TaskItemHyperlinkButton" BasedOn="{StaticResource BaseButtonStyle}">

        <Setter Property="Template" Value="{StaticResource ButtonTemplate}" />

        <Style.Triggers>
            <Trigger Property="IsCurrent" Value="true">
                <Trigger.ExitActions>
                    <BeginStoryboard Storyboard="{StaticResource PressedOff}" />
                </Trigger.ExitActions>
                <Trigger.EnterActions>
                    <BeginStoryboard Storyboard="{StaticResource PressedOn}"/>
                </Trigger.EnterActions>
            </Trigger>
        </Style.Triggers>
    </Style>