We have a webapp with a dark blue background (this is a branding decision, and we don't want to revisit it... yet). We want to indicate positive/negative change with the traditional "stock ticker" style of a green arrow up and red arrow down.
Problem: With red on a blue background we get bad visual effects (because of chromatic aberration I think... something I heard in a UX lecture a LOONG time ago).
There are a few obvious solutions - a light border for example. None are really appealing. I'm looking for any other creative approaches. Or maybe just pick a different color instead of the traditional red == bad?
Interesting to note - the top banner on stack exchange is blue, when there are unread messages it shows a red circle. The circle is styled with a red boxshadow blur. Things that make you go hmmm
EDIT: Igor-G points out this phenomenon is known as "chromostereopsis".