I really love the new CSS flexbox design possibilities. Especially flex-wrap: wrap can be a powerful tool to save some space (e.g. simple mobile navigation design pattern).
My Situation: I have this navigation, on desktops all items are lined in one line. With flex:auto the items fill up all the space. Now, when i resize the browser, at a certain point, when there is no more space left, flex-wrap automagically creates this second line for me.
See my small DEMO or have a look at this picture:

This is what tickles me: Only the first item is in the second row (when the first wrap happened). That's not really balanced and gives a lot of attention on this item. What i want is to distribute them equally. Is there a CSS-only no-hacks-included way that i am missing here?
EDIT: I do this layout for a dynamic web app. This navigation should fit different views and situations. So i don't want to care how many items there are going to be. The markup should ideally be a simple ul li list (no extra rows, no extra classes). So i am really looking for some kind of CSS parameter magic.
EDIT2: For better understanding: text-wrap: balance is a proposal to do basically the same only with chunks of pure text for typography.
EDIT3: See Bootstrap CSS framework grid model for example. Here you various columns-widths. You need to define how much space a column takes (third, quarter), for each device-width, for example: This colums takes a quarter of the width on a desktop, but only half of the width on a phone. wouldn't it be much cooler when browser could justify that?
EDIT4: Think of CSS-columns, here the content spans across the columns, but the content direction is only possible in N-form (column by column), imagine the same in Z-form (line by line).