AstroSage is a quiet, warm blog theme for long technical posts. Body text is set in a variable serif with optical sizing, at a comfortable reading measure, on a warm paper palette with an espresso dark mode. Every colour is a design token and meets WCAG contrast in both themes.
On wide screens a table of contents stays pinned beside the text and highlights the section you are reading. KaTeX math, Expressive Code blocks, and Mermaid and Excalidraw diagrams are all rendered at build time, so article pages ship only a few kilobytes of JavaScript.
For writing, it supports callouts, wiki-links between posts, footnotes, task lists, figures at column, wide and full width, series with part navigation, tags with post counts, archives and Pagefind search.
It also generates social preview images, a full-text RSS feed and a sitemap, and includes share links, quote sharing, a citation block with BibTeX, and optional GitHub-backed comments through utterances or giscus. The result is a fully static site that works on any host.
