On Fri, Jan 01, 2021 at 07:34:59PM +0100, michael-franzese@gmx.com wrote:
> I have done (require 'paren) before defining my functions.  It is working
> for (setq show-paren-style 'parenthesis), but not when using
> (setq show-paren-style 'expression).

[...]

There is a face `show-paren-match-expression': most probably you want to
tweak that one.

How did I find out? Well, I set show-paren-style to 'expression, set
point to an opening parenthesis and then did a `describe-face'.

Cheers
 - t