tachiyomi/app/src/main/res/values-night/themes.xml

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

    <!--===============-->
    <!-- Launch Screen -->
    <!--===============-->
    <style name="Theme.Splash" parent="Theme.Tachiyomi.Dark">
        <item name="colorBackgroundSplash">@color/backgroundDark</item>

        <item name="android:windowBackground">@drawable/splash_background</item>
        <item name="android:statusBarColor">?attr/colorBackgroundSplash</item>
        <item name="android:navigationBarColor">?attr/colorBackgroundSplash</item>
    </style>

</resources>