Frameworks come and go — Remix, Next, Gatsby, WordPress, Hugo, Hexo, TextPattern — but the "classic" CSS styling tactics stay. If you still use SASS and embrace the CSS inheritance — you're probably already using this technique.
Syntax highlighting is done using either highlight.js or prism.js. Once you've picked one, you'll have to set it up for code blocks: 1. within MDX and 2. outside MDX. That's how it works on all kinds of frameworks, not just Remix, although I'll post examples for Remix.
This setup is mostly a trivial task; however, there are a few niggles worth mentioning.
Vercel, our static website hosting service, makes it easy to set up page redirects, you can have up to 1024 redirects. It's all controlled from a single JSON file. Many things can go wrong in that file, stakes are quite high (starting with SEO) and any redirect mistakes can be hard to spot.