Syntax Highlighting: CSS Nesting rules don't seem to be highlighted correctly

CSS Nesting is now in the major browsers, and it seems like the highlighter for CSS still doesn’t recognize it as valid syntax.


This above shows the tr being highlighted as incorrect syntax, when in fact it does work.

I wasn’t sure if this is something that is part of the Codemirror lib, or something that gets imported to CM?

This does work in version 6, but indeed, the mode for 5 was written before these were a thing. It is unlikely to get updated at this point.