Tint selectableItemBackground with accent color

app/src/main/res/values/styles.xml

@@ -37,7 +37,7 @@
         <item name="layout_columnWeight">1</item>
         <!--<item name="layout_rowWeight">1</item>-->
         <item name="android:layout_height">@dimen/numeric_keypad_cell_height</item>
-        <item name="android:background">?android:attr/selectableItemBackground</item>
+        <item name="android:background">?android:attr/selectableItemBackgroundBorderless</item>
         <item name="android:gravity">center</item>
     </style>
 
@@ -122,6 +122,9 @@
     </style>
 
     <style name="ModalStyle" parent="Widget.Design.BottomSheet.Modal">
+        <!-- TODO: See if this can be set programmatically, or else we'd have to force users
+           ~ to declare a bottomSheetDialogTheme in their theme.
+         -->
         <item name="behavior_peekHeight">@dimen/peek_height_upper_limit</item>
     </style>