Adjust background color of main activity

app/src/main/res/layout/activity_main.xml

@@ -3,7 +3,8 @@
   xmlns:app="http://schemas.android.com/apk/res-auto"
   xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
-  android:layout_height="match_parent">
+  android:layout_height="match_parent"
+    android:background="@color/surface">
 
   <org.funkwhale.ffa.views.DisableableFrameLayout
     android:id="@+id/container"