I just pushed out a branch I've been noodling on over the last few days, it did a couple of things:

• Removed a file atmopshere.css that I was working on in the early days of Kumos, that was being imported but not used. This had a lot of CSS animations in it, that weren't being run... but I think your browser was maybe interpreting them so that it could run them later.
• Removed a lot of blur effects from around the site. These came with our CSS library so required me doing some overwrites. blur() is a really expensive on the GPU effect and we weren't getting any benefit from it. Buttons look less blurry I guess
• To resolve a bug with the navigation menu a long time ago I set the z-index of the header to 9999. Apparently, browsers have to actually calculate 9998 layers before that! No problem for modern devices, but your GPU has pretty minimal RAM so it was getting caught up on this. I've re-placed everything and am only using 10 layers now!
• Removed some very very very subtle gradients from the sidebar and header, which just removes some calculations that weren't needed

I know that this probably won't bring it down to 1%, and there are probably more modifications I can make to the library that we're importing for CSS to remove more of these GPU heavy effects, but this should at least make it possible to navigate the site 🙏