Need help with my twitch tracker app

Hey campers,
I am currently working on my twitch tracker app, and I’ve run into some issues with the design
Basically, I want this 4k wallpaper to be the background image…

…and I want the overall app to look something like this in the end:

However, I have promptly realized positioning text based on the background image is harder than I thought, since the browser displays it differently based on the resolution of the monitor. However, I still want to try it.

My question is: is there some way to do this using jQuery’s $(window).height() function? I have a hunch it might work,
but I have no clue as to how to implement it.

Thanks in advance!

Alternatively, I could just use css’ gradient function and achieve a nice purple gradient similar to this: