When we initialise TinyMCE in the HTML Customisation page we pass `content_css : "[% interface | html %]/[% theme | html %]/css/tinymce.css"`. Shouldn't we be passing the stylesheet/stylesheets of the interface we're editing rather than a specific tinymce sheet? That would more accurately represent how your content block is actually going to appear to the end user than it does now.. for example taking account of page-section classes if you add such a div into your markup? Or am I mis-understanding what the content_css option does?
`content_style:` could also be used to include the *UserCSS preference contents
Where I see challenges creeping in.. * Where we use a content block on both Staff and OPAC * Dynamically switching sheet after initial load when selecting the display location/interface
https://www.tiny.cloud/docs/tinymce/6/add-css-options/ is probably helpful