Default Font in Pages

I have a WPF application with a frame and pages.  I have a resource dictionary set in my app.xaml but cannot get the default styles in my resource dictionary to apply to my Pages.  In the resource dictionary, I have the following

<Style x:Key="defaultFontStyle" TargetType="Label"><Setter Property="FontFamily" Value="Verdana"/><Setter Property="FontSize" Value="12"/><Setter Property="Foreground" Value="White"/></Style>

Labels that I put in the main window (i.e. not in pages) work just fine.  But the style does not seem to propagate to labels within the pages.  What do I need to do to get this applied to the entire application, not just the main window?

Thanks for your help!

Dave 

Dave Taylor