Responsive SPA using React.js

Hi everyone!

In this challenge I haven't been able to do the bonus (yet). The biggest difficulty for me was to create an universal solution (because we get the time remaining to launch instead of launching date/time), but finally I figured it out.

I didn't want to use any of ready-to-use countdown templates you can find on some sites or github. I decided I'd learn the most if I create myself it from start to finish. Of course this brought a lot of problems ;) - of which the biggest was animation of flipping cards. I will definately return to this project to deal with it, but I think I need some inspiration from other solutions and some time to clear head.

Meantime I'd be very grateful for any remarks on existing code and tips for future development of the animation.