.map_box {
  width: 1000px;
  height: 1000px;
  background-image: url(../images/map.png);
  margin: 0 auto;
  background-repeat: no-repeat;
  background-size: contain;
  position: relative;
}
.map_box::before {
  content: '';
  position: absolute;
  width: 200px;
  height: 200px;
  top: 35%;
  left: 30px;
  background-size: contain;
  background-image: url(../images/长箭头-copy.png);
  background-repeat: no-repeat;
}