Based on the network request, it's a single 24.88KB HTML file hosted on nginx and a cache HIT status and current age of 725 seconds. There's no CSS, JS etc. The HTML file is pure html from what I can tell with no inline CSS/JS.
I achieved something similar for my site by putting the HTML file generated every few minutes on a single S3 bucket and putting CloudFlare in front with caching page rule on the HTML too (by default HTML is not cached by CF).
I achieved something similar for my site by putting the HTML file generated every few minutes on a single S3 bucket and putting CloudFlare in front with caching page rule on the HTML too (by default HTML is not cached by CF).