A CodePen by Johanna Ruiz. CSS Triforce webkit-dropshadow - Using pseudo elements and the filter-webkit-dropshadow property, I created this css trifore with a single empty html element.

index.html

<div class="triforce"></div>

style.css

*,
*:before,
*:after{
  box-sizing:border-box;
}
html{
  font-size:100%;
  min-height:100%;
}
.triforce{
  border-bottom:1.5em solid #FFCC00;
  border-left:1em solid transparent;
  border-right:1em solid transparent;
  position:absolute;
  display:inline-block;
  height:0;
  width:0;
  margin:-1.5em -1em;
  left:50%;
  top:50%;
  -webkit-filter: drop-shadow(0 2px 3px hsla(0,0%,0%,.25));
}
.triforce:before,
.triforce:after{
  border-bottom: 1.5em solid #FFCC00;
    border-left: 1em solid transparent;
    border-right: 1em solid transparent;
    content: '';
    height: 0;
    position: absolute;
    top: 1.5em;
    width: 0;
}
.triforce:before{
  left:0;
}
.triforce:after{
  right:0;
}