fix navigation color on start up

cyberwow/android/app/src/main/java/org/wownero/cyberwow/MainActivity.java

@@ -1,6 +1,7 @@
 package org.wownero.cyberwow;
 
 import android.os.Bundle;
+import android.graphics.Color;
 import io.flutter.app.FlutterActivity;
 import io.flutter.plugins.GeneratedPluginRegistrant;
 
@@ -8,6 +9,7 @@ public class MainActivity extends FlutterActivity {
   @Override
   protected void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
+    getWindow().setNavigationBarColor(Color.BLACK);
     GeneratedPluginRegistrant.registerWith(this);
   }
 }

cyberwow/android/app/src/main/res/values/styles.xml

@@ -4,5 +4,6 @@
         <!-- Show a splash screen on the activity. Automatically removed when
              Flutter draws its first frame -->
         <item name="android:windowBackground">@android:color/black</item>
+        <item name="android:navigationBarColor">@android:color/black</item>
     </style>
 </resources>