Custom CSS Error - Online Store editor session can't be published

Hi @Toast2000toast ,

Glad to support you today.

Your code doesn’t wrong but you should add the correct place. If your theme has a file theme.css or base.css, pls add that code under the file:

I hope you find the answer helpful.

Kind & Best regards,
GemPages Support Team.

If you add that code to Theme.liquid file, pls add that code inside the tag like this: