Add missing contentDescription to focusable controls.
diff --git a/res/values/styles.xml b/res/values/styles.xml
index a731443..0a6fe2f 100644
--- a/res/values/styles.xml
+++ b/res/values/styles.xml
@@ -23,11 +23,13 @@
     <style name="MinusButton">
         <item name="android:background">@drawable/btn_circle</item>
         <item name="android:src">@drawable/ic_btn_round_minus</item>
+        <item name="android:contentDescription">@string/description_minus_button</item>
     </style>
 
     <style name="PlusButton">
         <item name="android:background">@drawable/btn_circle</item>
         <item name="android:src">@drawable/ic_btn_round_plus</item>
+        <item name="android:contentDescription">@string/description_plus_button</item>
     </style>
 
     <style name="MoreButton">