I’ve lost track of the number of times I’ve had to refer to this article over the last several months. Flexbox is amazing, but sometimes it’s not the most intuitive.
“Our comprehensive guide to CSS flexbox layout. This complete guide explains everything about flexbox, focusing on all the different possible properties for the parent element (the flex container) and the child elements (the flex items). It also includes history, demos, patterns, and a browser support chart.”