diff --git a/res/layout/activity_main.xml b/res/layout/activity_main.xml
--- a/res/layout/activity_main.xml
+++ b/res/layout/activity_main.xml
@@ -17,7 +17,7 @@
             android:layout_width="match_parent"
             android:layout_height="?attr/actionBarSize"
             android:elevation="8dp"
-            app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar" />
+            android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar" />
 
         <FrameLayout
             android:id="@+id/container"