css 3d rotate example different size in safari than chrome - css

Question

I found an example of a 3d cube rotation hover effect that works great except for one thing. When I view it in chrome it's normal sized, and when I view it in safari it's double sized.
I really have no idea why this is happening since I don't see any zoom or webkit-scale happening, any thoughts on this?
http://jsfiddle.net/QMQLQ/
HTML:
<div class='box-scene'>
<div class='box'>
<div class='front face'>
<img src='http://placehold.it/180x180/' alt=''>
</div>
<div class="side face">
<p>This is back</p>
</div>
</div>
</div>
<div class='box-scene'>
<div class='box'>
<div class='front face'>
<img src='http://placehold.it/180x180/' alt=''>
</div>
<div class="side face">
<p>This is back</p>
</div>
</div>
</div>
CSS:
.box-scene {
-webkit-perspective: 700;
width: 400px;
height: 200px;
margin: auto;
z-index: 999;
}
.box-scene:hover .box {
-webkit-transform: rotateY(-90deg);
}
.box {
-webkit-transform: scale(1,1);
width: 180px;
height: 180px;
position: relative;
-webkit-transform-style: preserve-3d;
-webkit-transition: all 0.4s ease-out;
-webkit-transform-origin: 90px 90px -90px;
/* float: left; */
margin: 30px auto;
}
.face {
position: absolute;
width: 100%;
height: 100%;
-webkit-backface-visibility: visible;
-webkit-transform-origin: 0 0;
}
.front {
-webkit-transform: rotateY(0deg);
z-index: 2;
background: #d9d9d9;
}
.side {
background: #9dcc78;
-webkit-transform: rotateY(90deg);
z-index: 1;
left: 180px;
}