It's amazing that posting this on HN has not melted it down. Are you using an edge CDN like Cloudflare to provide caching?
For some reason his main.css is not compressed, so that would be the first thing to optimize.
The CSS on the other hand has TONS of comments which can be gotten rid of and minimized.
Edit: ah, not. Looks like it’s reachable from my landline (which is IPv4 only) but not from my 4G connection (which has IPv6).