Wish: give an unique ID to BODY for front and back cards

Hi, I wish a default front and back id (or class) to the body tag of the two faces of cards, to easilly differentiate them though CSS. I tryied trough javascript but I couldn’t - and it’s maybe too much to ask to the average user.
Thank you

You can just add a custom HTML tag to one side of the card to differentiate using Javascript.

I know, but I don’t know how (like most average user). I think it would be a meaningful semantic default easy to implement that would make easier to format cards for the average user.