Great to hear that you got it working.
If you delete the minified version of the CSS rules, the plugin will revert to using the unminified copy. This should make it easier for you to view and edit the rules.
In any case, you should never, ever edit theme or plugin files. Your changes will be reverted next time I release a new patch. You should create a child theme to your theme, then add your rules to your child theme. You should also make sure that your rules override the existing CSS rules. Please see here for an introduction on CSS specificity: https://stuffandnonsense.co.uk/archives/css_specificity_wars.html The “C” in CSS stands for cascading, so you will never need to edit plugin files.
kind regards