Home / Articles / Public Service Announcement: Careful With Your Nested Border-Radii Author Chris Coyier Published Dec 6, 2011 200+ popular business app integrations on MailChimp. When you have and element within another padded element, both with different backgrounds and both with border-radius, make sure the inside element’s border-radius is a bit less than the outer element. Otherwise it makes kind of a too-thick “hump” around the edges. Both have border radius of 20px; Inside element’s border radius reduced to 17px There probably is some fancy math you could do to figure out the perfect values, but I find eyeballing it works pretty well. This post brought to you by DICK™ (Details Improve Creative worK).