Hacker News Reader

Alternatively, you could specify the type of the source code so the user agent could handle the syntax highlighting—just like every other source code viewer ever written aside from those with idiosyncrasies related to the fact that they that belong to a special class called "Web browsers".

Tbh <pre> + monospace font + padding already makes a lot of code snippets readable, you can also write a 10 line js function to generate highlight for only the comments (to make them lesser shade of gray), i think that solves a lot of readability with very minimal work. Also I think there's no shame in using highlight.js

Pygments does this easily, depending on the source for generating HTML pages. It has been available for a long time. For more than a decade. Some blog generators use it, not only Python blog generators.