A theme is a visual appearance for the controls in the Operating System .Changing the themes in the Mobile , affects the appearance of the applications that has Theming in it .
With the support of Theming available in Windows Phone 7 , Here is a simple way to change the it . By Default , the theme is Dark Blue .
Note : I am using emulator here .
3. Select the Themes .
4. You can now change the Theme settings here.
Change the background and the assent color.
This is how the UI looks when I change the Theme.
For the Development , the Theming is implemented via the Resource Files.
The Visual Studio 2010 inserts the Dark Blue theme properties into App.xaml, in the resources collection.
Here's the screenshot of the App.XAML File .