.wrap {
    width: 100%;
    height: 400px;
    /* position: absolute; */
    top: 50%;
    /* margin-top: 3px; */
    background-color: #ff7f00;
    overflow: hidden;
    -webkit-perspective: 800px;
    -moz-perspective: 800px;
  }
  
  .photo {
    width: 320px;
    max-width: 70%;
    height: 260px;
    position: absolute;
    z-index: 1;
    box-shadow: 0 0 1px rgba(0,0,0,.01);
    -webkit-transition: all 0.6s;
    -moz-transition: all 0.6s;
    left: 50%;
    top: 50%;
    margin: -160px 0 0 -130px;
  }
  
  .photo .side {
    width: 100%;
    height: 100%;
    background: url(../img/background.png) no-repeat center;
    background-color: #eee;
    position: absolute;
    top: 0;
    right: 0;
    padding: 20px;
    box-sizing: border-box;
  }
  
  .photo .side-front { /*display: none;*/
  }
  
  .photo .side-front .image {
    width: 100%;
    height: 100%;
    /* line-height: 250px; */
    overflow: hidden;
  }
  
  .photo .side-front .image img { width: 100%; }
  
  .photo .side-front .caption {
    text-align: center;
    font-size: 16px;
    line-height: 0;
  }
  
  .photo .side-back { }
  
  .photo .side-back .desc {
    color: #ff7f00;
    font-size: 14px;
    line-height: 1.5em;
    margin-top: 40%;
  }
  
  .photo_center {
    left: 50%;
    top: 50%;
    margin: -160px 0 0 -130px;
    z-index: 999;
  }
  
  .photo-wrap {
    position: absolute;
    width: 100%;
    height: 100%;
    -webkit-transform-style: preserve-3d;
    -webkit-transition: all 0.6s;
    -moz-transform-style: preserve-3d;
    -moz-transition: all 0.6s;
  }
  
  .photo-wrap .side-front {
    -webkit-transform: rotateY(0deg);
    -moz-transform: rotateY(0deg);
  }
  
  .photo-wrap .side-back {
    -webkit-transform: rotateY(180deg);
    -moz-transform: rotateY(180deg);
  }
  
  .photo-wrap .side {
    -webkit-backface-visibility: hidden;
    -moz-backface-visibility: hidden;
  }
  
  .photo_front .photo-wrap {
    -webkit-transform: rotateY(0deg);
    -moz-transform: rotateY(0deg);
  }
  
  .photo_back .photo-wrap {
    -webkit-transform: rotateY(180deg);
    -moz-transform: rotateY(180deg);
  }
  
  .wrap .nav {
    width: 80%;
    height: 30px;
    line-height: 30px;
    position: absolute;
    left: 10%;
    bottom: 0;
    z-index: 999;
    text-align: center;
  }
  
  .nav .i {
    width: 30px;
    height: 30px;
    display: inline-block;
    cursor: pointer;
    background-color: #f4ca41;
    text-align: center;
    border-radius: 90%;
    -webkit-transform: scale(0.5);
    -webkit-transition: all 0.5s;
    -moz-transform: scale(0.5);
    -moz-transition: all 0.5s;
  }
  
  .nav .i_current {
    -webkit-transform: scale(0.8);
    -moz-transform: scale(0.8);
  }
  
  .nav .i_back {
    -webkit-transform: rotateY(-180deg) scale(0.8);
    -moz-transform: rotateY(-180deg) scale(0.8);
    background-color: #ff7f00;
  }