android-calculatorpp/calculatorpp/res/values/styles-metro-purple-theme.xml

<resources>

	<style name="metro_digit_button_style" parent="keyboard_button_style">
		<item name="android:background">@drawable/metro_button_dark</item>
	</style>

	<style name="metro_control_button_style" parent="metro_digit_button_style">
		<item name="android:background">@drawable/metro_button_light</item>
	</style>

	<style name="metro_purple_operation_button_style" parent="metro_digit_button_style">
		<item name="android:background">@drawable/metro_button_purple</item>
	</style>

	<style name="metro_control_image_button_style" parent="metro_control_button_style">
		<item name="android:padding">6dp</item>
	</style>

	<style name="metro_purple_theme" parent="default_theme">
		<item name="digitButtonStyle">@style/metro_digit_button_style</item>
		<item name="controlButtonStyle">@style/metro_control_button_style</item>
		<item name="controlImageButtonStyle">@style/metro_control_image_button_style</item>
		<item name="operationButtonStyle">@style/metro_purple_operation_button_style</item>
	</style>

</resources>