Can comments by a logged-in user be displayed at the top?

EDIT: I answered my own question! I was able to do this using 3 lines of CSS – thanks, flexbox! leaving this here in the hopes that it helps someone else someday 🙂

— original question —

Working on a site where the client wants to allow commenting on posts by both members (who will be able to log in to the site) and nonmembers. They would like comments by a logged-in user to be displayed at the top of the comments list, and “guest” comments to come up below.

Is there an easy way to do this without involving a plugin?

I’m aware of the “byuser” CSS class which allows for different styling of comments by a logged-in user. This will be helpful. But wondering if there’s also any way to re-order the comments.

Thanks in advance for any help!