Xevi parent
Out of curiosity, why do you need to use "margin-left: auto" when working with flexbox items? What is it that you're trying to do, which can't be solved with "justify-content" and "align-items"?
Not OP but I had a scenario where I had a row with a variable number of items, left-aligned, and then the final item had to be right-aligned. "margin-left: auto" on the final item achieves that effect.