动画在Safari中无法正常工作？

Question

由于某些原因，我的音乐部分会翻转divs＆＃39;没有正确显示？造成这种情况的原因是什么？

1st image-safari-screenshot：Reveals the back but not the text

2nd image-chrome-screenshot：Works beautifully

/* entire container, keeps perspective */
.flip-container {
    perspective: 1000px;
}
/* flip the pane when hovered */
.flip-container:hover .flipper, .flip-container.hover .flipper {
    -webkit-transform: rotateY(180deg);
    }

.flip-container {
  margin-right:0;
  padding-right: 0;
}
.flip-container, .front, .back {
    width: 300px;
    height: 300px;
  padding: 0;
  margin: 0;
}
/* flip speed goes here */
.flipper {
    -webkit-transition: 0.6s;
    transform-style: preserve-3d;
    position: relative;
}
/* hide back of pane during swap */
.front, .back {
    backface-visibility: hidden;
    position: absolute;
    top: 0;
    left: 0;
}
/* front pane, placed above back */
.front {
    z-index: 2;
    /* for firefox 31 */
    -webkit-transform: rotateY(0deg);
}
/* back, initially hidden pane */
.back {
    -webkit-transform: rotateY(180deg);
}

这是指向测试网站的链接 - lengtest.com