AI_Change_code/miniProgram/pages/index/index.wxss

/**index.wxss**/
.container{
  padding: 0;
}

.body{
  width: 100%;
  height: 100%;
  position: fixed;
  top: 50%;
  left: 0;
  transform: translateY(-50%);
}

.a_btn{
  position: fixed;
  z-index: 99;
  bottom: 26%;
  left: 50%;
  transform: translateX(-50%);
}

.a_btn image{
  height: 68rpx;
}