Pretty cool! Small thing: you should use button tags for the examples – you're losing a lot of built-in accessibility by using div tags (for instance keyboard navigation).<p>How does these handle being applied to anchor (a) tags? Some times you want links to appear as buttons :)
This looks pretty cool, very simple. What is flexy.css? There is 1 button color? Feel free to submit it to my new GitHub repo curation site: <a href="http://icodedis.tool.cards/" rel="nofollow">http://icodedis.tool.cards/</a>