adds grey background to (some) component headers.

[stopfstedt]

refs ilios/ilios#5091

[dartajax]

I think this looks good - well to me anyway - as far as looking dated, I can look in the mirror for that. I just wanted initially to point out that it had changed and some formatting may have gotten dropped. We can discuss.

[jrjohnson]

@stopfstedt & @dartajax - is this on a path to getting merged? Trying to close out final PRs before making a monorepo change.

edit- whoops hit the wrong button. Close instead of comment.

[stopfstedt]

proof of concept. it's not going anywhere at the moment, i'm closing it out.