One of my favorite Colorado community leaders and XAML Jedi, Shawn Kendrot, wrote a great article helping XAML developers dynamically style controls with the standard light and dark layouts. In his article, Shawn uses the Settings charm to show how to do it.
One of the things I love about Windows Store apps is their ability to integrate with the system. One of these integration points is the Settings Charm. I’m not going to show you how to create a settings flyout. There are already lots of examples out there that do this. There are even some helpers like the SettingsFlyout available in Callisto and the helper created by Jerry Nixon. Recently Tim Heuer made a change to the SettingsFlyout to set the background to white. This change allows your app to follow the guidelines. He also added a property that allows you to change what you want the background to be if you are not a fan of white.