tess.oconnor.cx is hosted on
mallow.cfhp.org, a server running Debian.
Most new content is written in Markdown or HTML.
Most old content is stored in Atom Entry Documents, which is what my previous blog software used for its backing store.
The content is all written in GNU Emacs. I use markdown-mode to edit Markdown documents, bikeshed-mode to edit Bikeshed documents, and nXML mode for editing Atom documents.
It's set entirely in generic font families.