MainWindow.xaml

<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        DataContext="{StaticResource Composition}"
        Title="{Binding ClockViewModel.Time}"
        FontFamily="Consolas"
        FontWeight="Bold">
    <StackPanel Name="Clock" Opacity=".4" HorizontalAlignment="Center" VerticalAlignment="Center" DataContext="{Binding ClockViewModel}">
        <TextBlock Text="{Binding Date}" FontSize="64" HorizontalAlignment="Center" />
        <TextBlock Text="{Binding Time}" FontSize="128" HorizontalAlignment="Center" />
        <StackPanel.Effect>
            <DropShadowEffect Color="Black" Direction="20" ShadowDepth="0" Opacity="0" RenderingBias="Performance" />
        </StackPanel.Effect>
        <StackPanel.Triggers>
            <EventTrigger RoutedEvent="MouseEnter">
                <BeginStoryboard>
                    <Storyboard>
                        <DoubleAnimation Storyboard.TargetName="Clock" Storyboard.TargetProperty="Opacity" From=".4" To="1" Duration="0:0:0.3" />
                        <DoubleAnimation Storyboard.TargetName="Clock" Storyboard.TargetProperty="(Effect).Opacity" From="0" To=".5" Duration="0:0:0.3" />
                        <DoubleAnimation Storyboard.TargetName="Clock" Storyboard.TargetProperty="(Effect).ShadowDepth" From="0" To="8" Duration="0:0:0.3" />
                    </Storyboard>
                </BeginStoryboard>
            </EventTrigger>
            <EventTrigger RoutedEvent="MouseLeave">
                <BeginStoryboard HandoffBehavior="SnapshotAndReplace">
                    <Storyboard>
                        <DoubleAnimation Storyboard.TargetName="Clock" Storyboard.TargetProperty="Opacity" From="1" To=".4" Duration="0:0:0.3" />
                        <DoubleAnimation Storyboard.TargetName="Clock" Storyboard.TargetProperty="(Effect).Opacity" From=".5" To="0" Duration="0:0:0.3" />
                        <DoubleAnimation Storyboard.TargetName="Clock" Storyboard.TargetProperty="(Effect).ShadowDepth" From="8" To="0" Duration="0:0:0.3" />
                    </Storyboard>
                </BeginStoryboard>
            </EventTrigger>
        </StackPanel.Triggers>
    </StackPanel>
</Window>