react-native-test-app/android/app/src/main/res/values/styles.xml

react-native-test-app provides a test app for all supported platforms as a package

<resources>

    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.MaterialComponents.DayNight.NoActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
    </style>

</resources>