centered the design

Author: CodeCLS

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

@@ -12,6 +12,7 @@
         android:layout_width="0dp"
         android:layout_height="0dp"
         app:defaultNavHost="true"
+        android:visibility="gone"
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
@@ -24,5 +25,6 @@
         android:layout_height="wrap_content"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="parent"
-        app:layout_constraintEnd_toEndOf="parent"/>
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintBottom_toBottomOf="parent"/>
 </androidx.constraintlayout.widget.ConstraintLayout>