styles.xml

<resources xmlns:android="http://schemas.android.com/apk/res/android">

    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light">
        <!-- Customize your theme here. -->
        <item name="android:actionBarStyle">@style/MyActionBarTheme</item>
        <item name="android:windowBackground">#F6F6F6</item>
    </style>
    <style name="MyActionBarTheme" parent="@android:style/Widget.Holo.Light.ActionBar">
        <item name="android:background">#F6F6F6</item>
    </style>
    <style name="AppTheme.Launcher">
        <item name="android:windowBackground">@drawable/launch_screen</item>
    <!-- Optional, on Android 5+ you can modify the colorPrimaryDark color to match the windowBackground color for further branding-->
    <!-- <item name="colorPrimaryDark">@android:color/white</item> -->
    </style>

</resources>