I was overjoyed when I saw that the latest versions of Safari for both OS X and iOS did away with the need to use -webkit- prefixes in CSS animations and flexbox. I’m still including them for the time being, and probably will for at least a year, to ensure compatability. But it’s as good a reason to point out that if you’re not on the flexbox train, you’re missing out on some powerful stuff.
CSS tricks has a great page called “A Complete Guide to Flexbox“, and I’ve been referring back to it constantly as I use it more and more in my current project. If you haven’t memorized all the nuances of flexbox yet, keep this one handy.