My issue with flexbox is that I can't seem to memorize all the settings I need to get boxes within boxes and content to either fill a box or the box to surround the content.

This is particular important on an SPA where I want the boxes to fill the screen but never overflow it. I manage eventually. I need to put the totally intuitive (sarcasm) min-width: 0, here and there, and a few other things here and there and eventually I get it.

I feel like I should be able to make a few css classes to cover all of this but I have yet to figure it out for every case.