This site is mainly set in GT America by Grilli Type, a modern hybrid of American Gothic and European Neo-Grotesk typefaces. mathematical expressions are set with in Computer Modern. Code is set in IBM Plex Mono by IBM.
This version of yklcs.com you are looking at is the product of 655 commits. The static site generator used is Soar 0.12.0, created by me. Continuous deployment is done through Github Actions. Hosting is done on AWS S3 and CloudFront.