Yet again, I created another CodeMirror 6 demo. It uses craftzdog's cm6-themes and is inspired by his demo site and the good old CodeMirror 5 demo.
Written in TypeScript. Used Remark/Unified for Markdown parsing.
You can try out the demo here.
Currently there is a bug with the code highlighting not registering properly in the production build. This causes a bunch of errors when using code blocks.