UnrealEngineUWP/Engine/Build/Android/Java/res/values-port/styles.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>

 	<style name="Theme.Black.AppCompat.NoActionBar.FullScreen" parent="@style/Theme.AppCompat.NoActionBar">
		<item name="android:windowNoTitle">true</item>
		<item name="android:windowActionBar">false</item>
		<item name="android:windowFullscreen">true</item>
		<item name="android:windowContentOverlay">@null</item>
		<item name="android:windowBackground">@android:color/black</item>
		<item name="android:colorBackground">@android:color/black</item>
	</style>

    <style name="UnrealBaseTheme" parent = "Theme.Black.AppCompat.NoActionBar.FullScreen" />

    <style name="UnrealSplashTheme" parent = "UnrealBaseTheme">
        <item name="android:windowBackground">@drawable/splashscreen_p</item>
        <item name="android:windowNoTitle">true</item>
        <item name="android:windowFullscreen">true</item>
    </style>

</resources>