Lovelace background picture and sliding cards

Hi, perhaps this has been mentioned somewhere but I couldn’t find an answer on my question here

I have a background picture set like this in my lovelace dashboard by adding:

background: center / cover no-repeat fixed url('/local/images/BnWRear.jpeg')
title: Longitude 9° Control Panel

at the top of the loavelace code. Works however its sticks to the card and it would be nice if the cards slide over the picture like on a iPhone or Whatsapp background. Are there attributes to set to make that happen. I have removed fixed form the statement but it doesn’t make a difference…