They are beautiful!
Thanks for sharing them 
If you’re interested, someone recently also shared a way to have markdown support with minimal setup. They might help with the coding cards as you don’t need to copy the syntax highlighting.
The default needed to be simple and also resilient against errors but that also makes it really unappealing. There was a suggestion floating around to change it and I remember both of those points were brought up.
But your code for the most part is simple and beautiful (the styling for hr, left-aligned text, the padding, more readable line-height). So hopefully, we can change the defaults to something better in the future.