I read over this support document to help set up a custom overriding editor.css file to stop displaying a dark background - https://www.joomlacontenteditor.net/support/tutorials/editor/create-a-custom-editor-stylesheet I set up a new editor.css file with the below code, set to custom.css in JCE Config & added templates/$template/css/editor.css The background is now white, but all other stying is now default, so I was wondering if the above document is still the correct way to do this?

@import url(theme.css);
@import url(bootstrap.css);
@import url(uikit3.css);
body {background-color: white;}

Thanks in advance, Andy

Apologies I've located the problem 🙁
I had done almost everything correct, including clearing site & browser cache. However, forgot about CDN cache. Once that cleared itself, all was OK :)