title: pseudo elemenst not working in Firefox
body: <p>pseudo elements :after, :before not working in Firefox, but work perfectly in Chrome.</p>
  
  <p>Can anyone explain how to fix it and why this occur:</p>
  
  <p><a href="http://jsfiddle.net/qn979byy/" rel="nofollow">Here is jsfiddle</a>
  <br/><br>
  HTML:</p>
  
  <pre><code> &lt;input type="checkbox" class="checkbox" checked&gt;
  </code></pre>
  
  <p>CSS:</p>
  
  <pre><code> .checkbox {
    position: relative;
    top: -0.375rem;
    margin: 0 1rem 0 0;
    left: 5px;
    cursor: pointer;
    display: inline-block;
    height: 9px;
    z-index: 0;
  }
  
  .checkbox::before {
    -webkit-transition: all 0.3s ease-in-out;
    -moz-transition: all 0.3s ease-in-out;
    transition: all 0.3s ease-in-out;
    content: "";
    position: absolute;
    left: 0;
    z-index: 2;
    width: 1.8rem;
    height: 1.8rem;
    border: 1px solid #CCCCCC;
  }
  
  .checkbox:checked::before {
      border: 3px solid #CCCCCC;
    -webkit-transform: rotate(-45deg);
    -moz-transform: rotate(-45deg);
    -ms-transform: rotate(-45deg);
    -o-transform: rotate(-45deg);
    transform: rotate(-45deg);
    height: 0.9rem;
  
    border-color: #8ECA24;
    border-top-style: none;
    border-right-style: none;
  }
  
  .checkbox::after {
    content: "";
    position: absolute;
    top: -0.125rem;
    left: 0;
    width: 1.1rem;
    height: 1.1rem;
    background: #fff;
    cursor: pointer;
  }
  </code></pre>