https://github.com/benjajaja/mdfried/
Markdown is really cool in the sense that you can still look at the raw text and read it easily. But one thing that always made me load up .md files in the browser was that it's just much easier to read when the headers are bigger.
So I wrote a markdown viewer that renders the headers as images. You need to configure your font once for it to work, can't really detect the terminal font. It obviously also renders inline images, which was another reason to use the browser.
And then, Kitty developed the novelty https://sw.kovidgoyal.net/kitty/text-sizing-protocol (I think it's now also implemented in Ghostty), which means we can skip the text-to-image processing and directly leverage that protocol.