body {
  overflow-x: hidden;
}
.app {
  width: 100%;
  height: 100%;
  padding-top: 45px;
  background: url(../../img/gngsbgxh.png) center no-repeat;
  background-size: 100% 100%;
}
.app a img {
  width: 100%;
  display: block;
  float: left;
}
.app a {
  width: 20%;
  display: block;
  float: left;
}