Fade out/in page transitions

I would like all of my site pages to fade out when you navigate away from a page, and then fade in when you arrive on a new page. It looks like this has been discussed before, but I've yet to find a code that works or conversation that was resolved. Ideally this code would allow me to change the duration of the fade as well. This is the only paid version of what I want to achieve, but there's a known conflict with the SquareKicker plugin I'm using. Thanks for your help.

https://conversiontracking.io/blog/squarespace-animation-loading-screen-page-transitions