I need "cue notes" in a document, just number so people can visually "jump"
to a paragraph quickly and match with a script.

So, the actual notes would be plain text, but I want to make a style where
the number (say, 23) lives in a box, with a small gap round it, and a yellow
background.

So far, I've got a box which is the full width of the page, which I don't
want, and no matter what I do (like "match style to selection") I can't get
it to "pick" the highlight colour!

Many thanks for any help. Yes, I've read sites, but none that cover a
highlight colour for a style, or a "just as big as the text" box format!