How to lay out two adaptive blocks that would not fall apart when the screen width changes?

Question

css

Example code

There are two responsive blocks with different widths. When the screen width changes, each of them changes its height depending on the inner content. How to make blocks of the same height for a responsive page?

Answer 1

codepen.io/anon/pen/XbNrmN =)
upd
can be done like this (more cross browser)
codepen.io/anon/pen/VLmZvX