If I had a time machine I would go back and ensure that DSSSL (https://en.wikipedia.org/wiki/Document_Style_Semantics_and_S...) was the standard that got up.

All hail the embedded Scheme interpreter to apply Style transformations!

Although I feel like we've already explored this with XSL. The XML syntax was perhaps too much to swallow.

You write your markup in an xml syntax, your scripts in a C syntax, and your styles in a lisp syntax... a perfect trio.