How to set a shadow for a triangle in css?

Question

css

how to set shadow for triangle in css It is for the die to have a common shadow

<div class="map_box">
  <div class="map_item">
  </div>
</div>

.map_box {
     width: 1000px;
     height: 500px;
     background: pink;
   }
  .map_item {
  position: absolute;
  display: block;
  width: 396px;
  height: 245px;
  background: #fff;
  top: 65px;
  left: 74px;
  box-shadow: 0 2px 4px 0 rgba(0, 0, 0, 0.5);
}
.map_item:after {
  content: "";
  height: 0;
  position: absolute;
  width: 0px;
  border-bottom: 123px solid transparent;
  border-left: 52px solid white;
  border-top: 123px solid transparent;
  right: -52px;;
  top: 1px;
  z-index: 2;
}
.map_item:before {
  content: "";
  height: 0;
  position: absolute;
  width: 0;
  border-bottom: 75px solid transparent;
  border-left:25px solid rgba(0,0,0, 0.6);
  border-top: 75px solid transparent;
  right: -23px;
  top: 0;
  filter:blur(5px);
  z-index: -1;
}

Answer 1

So?