Customize HeaderBackground (http://cyanbyfuchsia.wordpress.com/2013/04/29/winrt-settings-with-caliburn-micro/)

App.xaml.cs

protected override void Configure()
{
  _container = new WinRTContainer();

  _container.PerRequest<MainViewModel>()
            .PerRequest<AboutViewModel>();

  var viewSettings = new Dictionary<string, object>();
  viewSettings.Add("headerbackground", new SolidColorBrush(Colors.Red));
                        
  var settings = _container.RegisterSettingsService();
  settings.RegisterCommand<AboutViewModel>("Custom", viewSettings);
}