Applying background styles for Material Card View not working

[mburdett555]

In style.xml I have:
<style name="daycall" parent="CardView"> <item name="cardBackgroundColor">#777777</item> </style> <style name="daypass" parent="CardView"> <item name="cardBackgroundColor">#AAAAAA</item> </style>
In my onBindViewHolder for RecyclerView I use:
holder.timingClass.style(R.style.daypass)

However the changes do not apply, no background color for the card view is actioned. Is this a known problem?