Body text is set in Newsreader, a variable serif with optical sizing, at 18.5px on a 1.7 leading. Labels, dates and code use JetBrains Mono. The light theme is warm paper (#f8f2e6); the dark theme is espresso (#1f1a15).
Tools
The site is built with Astro and deployed as static files. Code is highlighted by Expressive Code, maths is rendered by KaTeX, and diagrams are drawn at build time from Mermaid and Excalidraw sources. For a tour of every element, see AstroSage: every element, set in type.