How to fix display of flexbox items in ie11?

Question

css

Good afternoon. I can't figure out why the .main block does n't work correctly in IE11!
https://jsfiddle.net/un68kwwo/1/ - it works well everywhere, but in IE11 it can't, although it has very good flexbox support.

Answer 1

1. Write for main in flex format: 0 0 auto;
2. Add content or height
3. IE and vh units: caniuse.com/#search=vh