ring-android/app/src/main/res/values-v27/styles.xml

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

    <style name="AppThemeBase.Fullscreen" parent="AppThemeBase">
        <item name="android:windowDrawsSystemBarBackgrounds">true</item>
        <item name="android:navigationBarColor">@color/transparent</item>
    </style>

    <style name="AppThemeBase.DarkToolbar" parent="AppThemeBase">
        <item name="android:windowTranslucentStatus">true</item>
    </style>

    <!-- Light themes -->

    <style name="AppTheme" parent="AppThemeBase">
        <item name="android:windowLightStatusBar">true</item>
        <item name="android:windowLightNavigationBar">true</item>
        <item name="android:statusBarColor">@color/transparent</item>
        <item name="android:navigationBarColor">@color/surface</item>
    </style>

    <style name="AppTheme.DarkToolbar" parent="AppThemeBase.DarkToolbar">
        <item name="android:windowLightNavigationBar">true</item>
        <item name="android:navigationBarColor">@color/surface</item>
    </style>

    <style name="AppTheme.Fullscreen" parent="AppThemeBase.Fullscreen">
        <item name="android:windowLightStatusBar">true</item>
        <item name="android:windowLightNavigationBar">true</item>
    </style>
</resources>