Hi Andrew
The Site you will find here
www.meerkaemper.ch/staging.
attached screenshots and description.
when I manipulate the code in browser developper tools, it changes the color.
The same code in custom css, or your code in custom.css of template (helix3.03) don't affect the color.
Changes directly in modules > style.css are also working, but only as workaround because of future updates will overwrite the changes.
Regards and thank you , Heinz