A great overview from Chris from CSS Tricks about flex-box and how to get the best browser support by using a little of the old and new together.
Flexbox is pretty awesome and is certainly part of the future of layout. The syntax has changed quite a bit over the past few years, hence the “Old” and “New” syntax. But if we weave together the old, new, and in-between syntaxes, we can get decent browser support. Especially for a simple and probably the most common use case: order-controlled gridsAn excerpt from Using Flexbox: Mixing Old and New for the Best Browser Support