How to do backface hiding when -webkit-backface-visibility doesn't work!

card.css

/* 
  The back of the card is rotated 180 degrees from the card itself, giving
  the illusion that it really is the back!  Unfortunately hiding the back
  face of both "faces" doesn't work with webkit builds (requires Snow Leopard!)
  but we set it anyway.
*/
.card #back { -webkit-transform: rotateY(180deg); }
.card .face { -webkit-backface-visibility: hidden; }

/*
  Flipping the '.card' is simple, just rotate it 180 degrees.
*/
.card {
  -webkit-transform-style: preserve-3d;
  -webkit-transition-property: all;
  -webkit-transition-timing-function: linear;
}
.card:hover {
  -webkit-transform: rotateY(180deg); 
}

/*
  Flipping the faces is not so simple when the browser doesn't support the
  '-webkit-backface-visibility' property correctly!  We have to fake it so
  that the opacity of the '.face' changes such that, when it's at 90 degrees
  rotation, the opacity is 0.

  The transition from opacity 1 to 0, or vice-versa, is quick but delayed 
  in both directions for the face that is being revealed.  In other words, as
  the front face nears 90 degrees on its way to the back, it suddenly changes
  its opacity.  As the back face, coming from back to front, passes 90 degrees
  it suddenly increases it opacity.
*/
.card .face {
  -webkit-transition-property: opacity;
  -webkit-transition-timing-function: linear;
}
.card:hover #back,  .card #front { opacity: 1; }
.card:hover #front, .card #back  { opacity: 0; }

/* To make it easier to manage, timings are in one big block here! */
.card       { -webkit-transition-duration: 2.0s; }                   /* 100% */
.card .face { -webkit-transition-duration: 0.2s; }                   /*  10% */
.card:hover #back,  .card #front { -webkit-transition-delay: 1.0s; } /*  50% */
.card:hover #front, .card #back  { -webkit-transition-delay: 0.8s; } /*  40% */

card.html

<div class="card">
  <!-- This div is only here to ensure that the inner '.face' elements obey the padding of the '.card' -->
  <div>
    <div id="front" class="face">
      <h1>Front!</h1>
    </div>

    <div id="back" class="face">
      <h1>Back!</h1>
    </div>
  </div>
</div>