Flip Cards using GSAP - help with resize position

Hi all I thought I had figured out how to create nice flip cards using GSAP, all works well until I resize the window or rotate the screen on a mobile device and the cards positions go wrong.

I think this is to do with GSAP X and Y properties but I don't really know where to start unpicking this or understanding what else i need to add, can anyone help please?

 

File attached for ref