In this case and when there is no default action for an icon (like for some domains), the background will not be shown by default w/o cardmoddind.
Otherwise the background may be hidden by adding “opacity: 0” to “.container::before” like here:
🔹 Card-mod - Add css styles to any lovelace card - #6789 by Ildar_Gabdullin
It worked for me, thanks for sharing 