anchor.diff:        -webkit-box-sizing: border-box;
       }
   
  -    input, button {
  +    input, button, .button {
         display: block;
         border: none;
         border-radius: 10px;
  
positive.code:   var eventToBindTo = ('ontouchstart' in window) ? 'touchstart' : 'click';
  
    document.addEventListener('DOMContentLoaded', function(){
      var $front_back_container = document.querySelector('#f1_container');
  
      document.querySelector('.flip-to-back').addEventListener(eventToBindTo, function(event){
        event.preventDefault();
        addClass($front_back_container, 'flipped');
      });
  
      document.querySelector('.flip-to-front').addEventListener(eventToBindTo, function(event){
        event.preventDefault();
  
negative.code:       margin: 20px 13px;
  
      }
      .flip-to-back, .flip-to-front, .forgot-password {
        background-image: -webkit-gradient(linear, 50% 0%, 50% 100%, color-stop(0%, #262626), color-stop(100%, #404141));
        color: #c2c2c2;
        margin-top: 30px;
  