Does anyone know the drawbacks of simply using:

    .container {
      display: table;
      width: 100%;
    }

See bottom example here http://codepen.io/jrf0110/pen/xgXPGj

I've never had to use the clearfix hack (that's probably a lie, but I can't recall a time in my career where I didn't just use the display: table; width: 100%; method)