Why has the info bar gone red?

A red info bar means you've entered an unknown term — one Styleworks doesn't recognise, so it can't work out on its own what PerfectIt should look for. Nothing is wrong: Styleworks just needs one more piece of information, the search term (the “bad” form PerfectIt should find).

Add the search term with (not …) or should replace …. For example, Styleworks doesn't know that AMA style prefers kidney to renal, so:

kidney (not renal) 

kidney should replace renal 

 Either form works — they mean the same thing. As soon as Styleworks has both the preferred term and the search term, the info bar turns green and the term is ready for PerfectIt.