Hello timothy
Do you need your own styles specifically, or are you just looking for something more language-specific than the general-purpose code stylesheet? If the latter, this is an old problem - see
https://bugs.dokuwiki.org/index.php?do=details&task_id=167. I followed the advice to comment out $geshi->enable_classes(); (although since the date of that post it's moved to line 785 of inc/parserutils.php) and I'm now seeing the colours defined in the GeSHi language files.
Hope that helps!