book-of-gehn/book-of-gehn.github.io ? reverse-engineered prompt

Build me a clean static personal site for a blog called Book of Gehn. It should feel like an old school technical blog, fast, readable, and easy to host on GitHub Pages. I want a home page with recent posts, separate article pages, and simple archive or topic browsing for things like cryptography, reverse engineering, maths, and other nerdy notes. There should also be a basic slides section for talks or presentations.

Please include the normal blog essentials like RSS and Atom feeds, a sitemap, robots.txt, and good page metadata for sharing. Keep the design lightweight, mostly HTML and CSS with just a little JS where it actually helps. Make the typography nice, code snippets easy to read, and the whole thing mobile friendly.

If there is already content in the articles, assets, images, or slides folders, use and connect that instead of making fake placeholders. Look up current GitHub Pages friendly approaches online if you need to.