Fix: dark app bar in Article activity

Author: proletarius101

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

@@ -17,7 +17,7 @@
             android:layout_width="match_parent"
             android:layout_height="?attr/actionBarSize"
             app:navigationIcon="@drawable/ic_back"
-            style="@style/Widget.MaterialComponents.Toolbar.PrimarySurface" />
+            style="@style/Widget.MaterialComponents.Toolbar.Surface" />
 
     </com.google.android.material.appbar.AppBarLayout>