NewPipe/app/src/main/res/values-v21/styles.xml

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

    <style name="Base.V21.OpeningTheme" parent="Base.V7.OpeningTheme">
        <item name="android:navigationBarColor">@color/light_youtube_primary_color</item>
    </style>

    <style name="Base.OpeningTheme" parent="Base.V21.OpeningTheme" />

    <style name="Base.V21.LightTheme" parent="Base.V7.LightTheme">
        <item name="android:navigationBarColor">@android:color/transparent</item>
    </style>

    <style name="Base.LightTheme" parent="Base.V21.LightTheme" />

    <style name="Base.V21.DarkTheme" parent="Base.V7.DarkTheme">
        <item name="android:navigationBarColor">@android:color/transparent</item>
    </style>

    <style name="Base.DarkTheme" parent="Base.V21.DarkTheme" />

    <style name="Base.V21.BlackTheme" parent="Base.V7.BlackTheme">
        <item name="android:navigationBarColor">@android:color/transparent</item>
    </style>

    <style name="Base.BlackTheme" parent="Base.V21.BlackTheme" />

</resources>