It's essentially as simple as the title, I'm trying to add the border-radius property to the .su-spoiler class in the admin settings page CSS editor (nice editor, by the way, far superior to most in-browser CSS editors in WP that I've seen). However, upon adding that border-radius property, I get blank corners instead of nice curved corners.
I don't want to post a link to my page, as it's on my local machine, however, I'm going to try to put a screenshots here.
Had to use imgur:
By the way, though I'm posting for support, this plugin is frickin' AWESOME. You've done the entire WP community a solid, sir. Good show.