I'm on Firefox ESR, and while the pages functioned just fine, the performance is...lacking. I think the degraded experience mostly comes down to crappy framerates on the parallax effect.

Yah I'm on a 2016 15" MBP running 10.13.4 and Safari 11.1 and the site is almost unusable for me. If you want more specific information or would like me to test fixes you can email me at my user name @ gmail.com

This site definitely kills the Firefox on both Mac and Android (can barely scroll or not at all). Hopefully not a sign of things to come...

The <div class="top-shadow"> covers the scroll bar at the top of the browser window (in Firefox) effectively rendering the scroll bar disabled for the top 1/3 of the window. Additionally, page down and space keys are disabled for navigation. I'm not sure its possible to scroll using any key on the keyboard.

Pretty much kills Safari. Me thinks you need a better scroll library / implementation.