How to set automation group on/off color in theme?

I am trying to figure out how to set specific on/off colors for a group entity I have on my Lovelace cards.

The group has several automation buttons under it, but I would like to automatically see the group state and toggle them all together and it would be nice to have different colors depending on state like I have for switches…

Do I need to enhance the Html? Create a template or something like that?

Edit: I am loooking for different icon color depending on the group state btw