res/values/themes.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
/*
**
** Copyright 2017 The Android Open Source Project
**
** Licensed under the Apache License, Version 2.0 (the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
**
**     http://www.apache.org/licenses/LICENSE-2.0
**
** Unless required by applicable law or agreed to in writing, software
** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
*/
-->

<resources>
    <!-- This must be a fullscreen theme for the alarm to be able to turn the screen on. -->
    <style name="AlertFullScreenTheme" parent="android:Theme.Material.Wallpaper.NoTitleBar" />

    <style name="PreferenceTheme" parent="@style/PreferenceThemeOverlay.v14.Material">
        <item name="switchPreferenceStyle">@style/SettingsSwitchPreference</item>
        <item name="preferenceCategoryStyle">@style/SettingsPreferenceCategory</item>
        <item name="preferenceStyle">@style/SettingsPreference</item>
        <item name="dialogPreferenceStyle">@style/SettingsDialogPreference</item>
    </style>

    <style name="CellBroadcastSettingsTheme" parent="@android:style/Theme.DeviceDefault.Settings">
        <item name="preferenceTheme">@style/PreferenceTheme</item>
    </style>

</resources>