Marquee responsive

Hi, I want to add a marquee effect to my website. I have followed tutorial and can get it working but then when I change screen size it breaks.

Can someone point me to a tutorial on how to do this and make it fluid to different screen sizes?
Also, can someone explain to me the principal of why this isn’t working. I am assuming I need to make sure all of the unit sizes I am using are fluid or something. Maybe I even need custom code.


Here is my public share link: LINK
(how to access public share link)