html,body,.wrap {
   height: 100%; 
}
.wrap .inner {
    background:url('../images/loading.jpg') no-repeat;
    width: 100%;
    height: 17rem;
    background-size: cover;
    position: relative;
}
.wrap .inner .head {
  position: absolute;
  width: 100%;
  height: 1.1rem;
}
.wrap .inner .btns {
  position: absolute;
  width: 100%;
  height: 1.1rem;
  top: 11.8rem;
  display: flex;
  justify-content: center;
}
.wrap .inner .btns .down {
  width: calc(100% - 1.1rem);
  height: 1.1rem;
  border-radius: .6rem;
}