The fontTools section is the part I keep thinking about. Replacing the em dash glyph by compositing two hyphens via GlyphComponent is not something you reach for unless you really know your way around type rendering. Most frontend devs would have just swapped the character in the source, which doesn't survive the markdown processor. Doing it at the font level is the correct solution and it's a much harder problem than it looks.
The text-transform trick is more accessible but the same logic applies, the CSS has to protect code blocks from the lowercasing, which is a real edge case. It's a genuinely well-crafted technical solution underneath the poem.