RE: [css-customproperties] is this good or bad?

[Tab Atkins Jr.:]
> 
> I don't see how it impacts vars at all.  It's just a convergent use of
> naming in a relatively unimportant place.
> 
IE actually cascades unknown properties and reflects them in the OM i.e.
this behavior is not limited to names with an underscore prefix. I would
not worry about the apparent naming collision.