refactor: adjust for landscape

app/src/main/AndroidManifest.xml

@@ -127,10 +127,9 @@
                 android:value="true" />
         </service>
 
-        <!-- zxing for QR Code scanning: lock portrait orientation -->
         <activity
             android:name="com.journeyapps.barcodescanner.CaptureActivity"
-            android:screenOrientation="portrait"
+            android:screenOrientation="unspecified"
             tools:replace="screenOrientation" />
 
         <activity

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

@@ -61,6 +61,7 @@
                 android:id="@+id/tab_layout"
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
+                app:tabGravity="fill"
                 app:tabIconTint="@color/tab_color_selector"
                 app:tabIndicatorColor="@color/selectedColor" />
         </com.google.android.material.appbar.AppBarLayout>