为什么我的翻转动画不工作在chrome和safari浏览器

第一次发帖。对不起，如果我的代码有点乱，我仍然是一个初学者，我一直试图使这个翻转动画在chrome和safari上工作。它可以在firefox上工作，但我不明白为什么翻转动画不能在chrome上正常工作。

function flip(){
  document.getElementById('card').classList.toggle('flip');
}
function flip2(){
  document.getElementById('card2').classList.toggle('flip');
}
function flip3(){
  document.getElementById('card3').classList.toggle('flip');
}

h4{
	font-size: 2em;
}
#week-wrap {
	height: auto;  
	max-width: 100%; 
	width: auto; 
	background-color: #efefef;
	text-align: center;
}
#card, #card2, #card3 {
	text-align: center;
    position: relative;
	display: inline-block;
   max-width: 30%;
  cursor:pointer;
  margin: 1%;
-webkit-transition: all 1s ease;  
  transition: all 1s ease;
	 
-webkit-transform-style: preserve-3d;
  transform-style: preserve-3d;
  
  -webkit-backface-visibility: hidden; 
 backface-visibility: hidden;
 border-style: solid; 
    
}
#back{
  top:0;
  left:0;
  -webkit-backface-visibility: hidden;
  backface-visibility: hidden;
  
   
  position: absolute; 
  
  color:white;
  background-color: teal;
  width: 100%;
  height: 100%; 
}
#back{
	-webkit-transform: rotateY(180deg);
  transform: rotateY(180deg);
   
   
}
.figcaption {
	text-align: center; 
    width:100%; 
  height:0;
	font-size: 4em; 
  line-height: 0;
	color:white;
    position:absolute; 
  top:10%;
    z-index:1;
}
#card img {
	-webkit-display:block;
    display:block;
    
    max-width: 100%; 
}
#card2 img {
    display:block;
    max-width: 100%; 
}
#card3 img {
    display:block;
    max-width: 100%; 
}
.flip{
	-webkit-transform: rotateY(180deg);
  transform: rotateY(180deg);
  
    
}

<div id="week-wrap">
<div id="card" onclick="flip()">
	<div class="figcaption">Front</div>
	<img src="http://www.petakids.com/wp-content/uploads/2015/11/Baby-Bunny.jpg" />
  <div id="back"><h3>Back</h3>
  </div> 
  
</div>
    
    <div id="card2" onclick="flip2()">
	<div class="figcaption">Front </div>
	<img src="http://www.petakids.com/wp-content/uploads/2015/11/Baby-Bunny.jpg" />
      <div id="back"><h3>Back</h3>
  </div> 
        
      
</div>
      
       <div id="card3" onclick="flip3()">
	<div class="figcaption">Front </div>
	<img src="http://www.petakids.com/wp-content/uploads/2015/11/Baby-Bunny.jpg" />
         <div id="back"><h3>Back</h3>  </div> 
  </div>
  </div>