Hi, we are running our website on Helix 2.0.11 und Page Bilder Pro 3.8.9

Last week I upgraded from joomla 3 to 4 and first it seemes without problems.

Now I wanted to modify the custom.css of Helix. But when I check on Joomla the site templates and I select Helixultimate, I can not open the css files. When I try to open any file, I get this error message:

"3 arguments are required, 2 given"

Followed by a list of errors.

How can I solve this problem? Thank you for your help.