How to update Theme Mail CSS?


I need to update the CSS stylesheet for my email theme. So I went to the Mautic themes directory, opened the theme directory I use, openend the css folder and edited the css file there.

I then deleted the cache directory, emptied the Cloudflare cache, and hit Contrl + F5 for a forced rerefsh of the browser cache. The Mautic cache directory was recreated successfully.

But still the old css is loaded in the email.

What do I need to do more to get this working?