There seems to be a bug in this blog's stylesheet where the headings are significantly lower contrast if the browser renders prefers-color-scheme as dark instead of light.
I had my browser/OS in light mode, so the contrast was excellent, but I tried dark mode just to see what would happen, and it was... not excellent.
I had my browser/OS in light mode, so the contrast was excellent, but I tried dark mode just to see what would happen, and it was... not excellent.