.footer-mask {
  position: fixed;
  z-index: 99;
  width: 100%;
  top: 0;
  left: 0;
  height: 100%;
  background: rgba(0, 0, 0, 0.2);
}
.footer-nav {
  position: fixed;
  z-index: 100;
  width: 100%;
  bottom: 0px;
  -webkit-transform: translateY(3.5em);
  transform: translateY(3.5em);
  background-color: #fff;
  color: #727272;
  font-size: 15px;
  -webkit-transition: -webkit-transform 0.3s ease-out;
  transition: -webkit-transform 0.3s ease-out;
  transition: transform 0.3s ease-out;
  transition: transform 0.3s ease-out, -webkit-transform 0.3s ease-out;
}
.footer-nav a {
  color: #727272;
}
.footer-nav.show {
  -webkit-transform: translateY(0em);
  transform: translateY(0em);
}
.footer-nav .nav {
  display: -webkit-box;
  text-align: center;
  line-height: 3.5em;
}
.footer-nav .nav .item {
  position: relative;
  -webkit-flex-basis: 0;
  -webkit-box-flex: 1;
  overflow: hidden;
}
.footer-nav .nav .item .text {
  display: block;
}
.footer-nav .nav .item .text .icon {
  display: inline-block;
  width: 1em;
  height: 1em;
  vertical-align: middle;
  background-image: url(http://s.yuantutech.com/i4/40c3f964acde19f50985e833cb7f9901-102-102.png);
  background-size: 100% 100%;
  margin-top: -3px;
  margin-right: 2px;
}
.footer-nav .nav .item.open {
  overflow: visible;
}
.footer-nav .nav .item.open .dialog {
  -webkit-transform: translateY(-4.5em);
  transform: translateY(-4.5em);
  opacity: 1;
  z-index: 100;
}
.footer-nav .nav .item .dialog {
  position: absolute;
  width: 100%;
  bottom: 12px;
  text-align: center;
  line-height: 3em;
  -webkit-transform: translateY(-4em);
          transform: translateY(-4em);
  opacity: 0;
  z-index: -1;
  -webkit-transition: opacity 0.3s ease-out, -webkit-transform 0.3s ease-out;
  transition: opacity 0.3s ease-out, -webkit-transform 0.3s ease-out;
  transition: transform 0.3s ease-out, opacity 0.3s ease-out;
  transition: transform 0.3s ease-out, opacity 0.3s ease-out, -webkit-transform 0.3s ease-out;
  -webkit-transition: -webkit-transform 0.3s ease-out, opacity 0.3s ease-out;
  font-size: 12px;
}
.footer-nav .nav .item .dialog:after {
  content: "";
  width: 21.75px;
  height: 11.75px;
  background-image: url(http://s.yuantutech.com/i4/d299cd38df205e6ecfcfeecd8f2486a2-87-47.png);
  background-size: 100% 100%;
  position: absolute;
  bottom: -11px;
  left: 50%;
  margin-left: -11px;
}
.footer-nav .nav .item .dialog .inner {
  display: inline-block;
  background-color: #fff;
  max-width: 100%;
}
.footer-nav .nav .item .dialog .inner li a {
  display: block;
  margin: 0 1em;
}