bike-weapp/pages/poster/poster.wxss

page{
  height: 100%;
}
.box{
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  background:linear-gradient(0deg,rgba(24,213,185,1) 0%,rgba(89,240,202,1) 100%);
  position: relative;
}
.box .position{
  position: absolute;
  top: 21%;
}