TheXamlGuy.TaskbarGroup/TheXamlGuy.TaskbarGroup.Flyout/Controls/TaskbarButtonFlyout.xaml

<ResourceDictionary
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:controls="using:TheXamlGuy.TaskbarGroup.Flyout.Controls">
    <ResourceDictionary.ThemeDictionaries>
        <ResourceDictionary x:Key="Default">
            <AcrylicBrush
                x:Key="AcrylicBackgroundFillColorBrush"
                BackgroundSource="HostBackdrop"
                FallbackColor="#2C2C2C"
                TintColor="#2C2C2C"
                TintOpacity="0.8" />
            <StaticResource x:Key="TaskbarButtonFlyoutBorderBrush" ResourceKey="SurfaceStrokeColorDefaultBrush" />
            <StaticResource x:Key="TaskbarButtonFlyoutBackgroundBrush" ResourceKey="AcrylicBackgroundFillColorBrush" />
            <Thickness x:Key="TaskbarButtonFlyoutBorderWidth">1</Thickness>
        </ResourceDictionary>
        <ResourceDictionary x:Key="Light">
            <AcrylicBrush
                x:Key="AcrylicBackgroundFillColorBrush"
                BackgroundSource="HostBackdrop"
                FallbackColor="#F9F9F9"
                TintColor="#FCFCFC"
                TintOpacity="0.8" />
            <StaticResource x:Key="TaskbarButtonFlyoutBorderBrush" ResourceKey="SurfaceStrokeColorDefaultBrush" />
            <StaticResource x:Key="TaskbarButtonFlyoutBackgroundBrush" ResourceKey="AcrylicBackgroundFillColorBrush" />
            <Thickness x:Key="TaskbarButtonFlyoutBorderWidth">1</Thickness>
        </ResourceDictionary>
    </ResourceDictionary.ThemeDictionaries>
    <AcrylicBrush
        x:Key="NotificationFlyoutPresenterBackgroundAccentBrush"
        BackgroundSource="HostBackdrop"
        FallbackColor="{ThemeResource SystemAccentColorDark1}"
        TintColor="{ThemeResource SystemAccentColorDark1}"
        TintOpacity="0.8" />
    <Style TargetType="controls:TaskbarButtonFlyout">
        <Setter Property="BorderThickness" Value="{ThemeResource TaskbarButtonFlyoutBorderWidth}" />
        <Setter Property="BorderBrush" Value="{ThemeResource TaskbarButtonFlyoutBorderBrush}" />
        <Setter Property="Background" Value="{ThemeResource TaskbarButtonFlyoutBackgroundBrush}" />
        <Setter Property="CornerRadius" Value="{ThemeResource OverlayCornerRadius}" />
        <Setter Property="HorizontalContentAlignment" Value="Stretch" />
        <Setter Property="VerticalContentAlignment" Value="Stretch" />
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="controls:TaskbarButtonFlyout">
                    <Border x:Name="Container" Margin="{TemplateBinding Margin}">
                        <Grid x:Name="LayoutRoot">
                            <Border
                                x:Name="BackgroundElement"
                                HorizontalAlignment="Stretch"
                                VerticalAlignment="Stretch"
                                Background="{TemplateBinding Background}"
                                BackgroundSizing="OuterBorderEdge"
                                BorderBrush="{TemplateBinding BorderBrush}"
                                BorderThickness="{TemplateBinding BorderThickness}"
                                CornerRadius="{TemplateBinding CornerRadius}">
                                <Border.Transitions>
                                    <TransitionCollection>
                                        <EntranceThemeTransition x:Name="EntranceThemeTransition" />
                                    </TransitionCollection>
                                </Border.Transitions>
                                <Grid>
                                    <ContentControl
                                        x:Name="ContentPresenter"
                                        Margin="{TemplateBinding Padding}"
                                        HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
                                        VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"
                                        Content="{TemplateBinding Content}"
                                        ContentTemplate="{TemplateBinding ContentTemplate}"
                                        ContentTransitions="{TemplateBinding ContentTransitions}" />
                                </Grid>
                            </Border>
                        </Grid>
                        <VisualStateManager.VisualStateGroups>
                            <VisualStateGroup x:Name="PlacementStates">
                                <VisualState x:Name="DefaultPlacement" />
                                <VisualState x:Name="BottomPlacement">
                                    <VisualState.Setters>
                                        <Setter Target="EntranceThemeTransition.FromHorizontalOffset" Value="0" />
                                        <Setter Target="EntranceThemeTransition.FromVerticalOffset" Value="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=TemplateSettings.Height}" />
                                    </VisualState.Setters>
                                </VisualState>
                                <VisualState x:Name="TopPlacement">
                                    <VisualState.Setters>
                                        <Setter Target="EntranceThemeTransition.FromHorizontalOffset" Value="0" />
                                        <Setter Target="EntranceThemeTransition.FromVerticalOffset" Value="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=TemplateSettings.NegativeHeight}" />
                                    </VisualState.Setters>
                                </VisualState>
                                <VisualState x:Name="LeftPlacement">
                                    <VisualState.Setters>
                                        <Setter Target="EntranceThemeTransition.FromHorizontalOffset" Value="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=TemplateSettings.NegativeWidth}" />
                                        <Setter Target="EntranceThemeTransition.FromVerticalOffset" Value="0" />
                                    </VisualState.Setters>
                                </VisualState>
                                <VisualState x:Name="RightPlacement">
                                    <VisualState.Setters>
                                        <Setter Target="EntranceThemeTransition.FromHorizontalOffset" Value="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=TemplateSettings.Width}" />
                                        <Setter Target="EntranceThemeTransition.FromVerticalOffset" Value="0" />
                                    </VisualState.Setters>
                                </VisualState>
                            </VisualStateGroup>
                            <VisualStateGroup x:Name="ThemeStates">
                                <VisualState x:Name="DefaultTheme" />
                                <VisualState x:Name="ColorPrevalenceTheme">
                                    <VisualState.Setters>
                                        <Setter Target="BackgroundElement.Background" Value="{ThemeResource TaskbarButtonFlyoutPresenterBackgroundBrush}" />
                                    </VisualState.Setters>
                                </VisualState>
                            </VisualStateGroup>
                        </VisualStateManager.VisualStateGroups>
                    </Border>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</ResourceDictionary>