Comment by ruuda

I checked the source and it does indeed mention https://wordpress.org/themes/blankslate/, but judging from the screenshot there, that theme is just really a blank theme with no style at all, and it was used to include a different stylesheet.

The real style is at https://coding.napolux.com/wp-content/themes/coding.napolux...., which looks like normalize.css followed by a Wordpress adaptation of my stylesheet.

The similarity is more than superficial, the footer headers match exactly.