app/src/main/res/values/themes.xml

<resources>

    <style name="AppTheme" parent="Theme.AppCompat.DayNight">
        <item name="colorAccent">@color/accent</item>
        <item name="preferenceTheme">@style/PreferenceThemeOverlay</item>
    </style>

    <style name="AppTheme.NoActionBar" parent="AppTheme">
        <item name="windowActionBar">false</item>
        <item name="windowNoTitle">true</item>
    </style>

</resources>