css绘制三角形

<div class="sanjiao"></div>
.sanjiao {
  &::after {
    content: "";
    border-top: 8px solid #a16ee7;
    border-left: 6px solid transparent;
    border-right: 6px solid transparent;
    position: absolute;
    left: 50%;
    -webkit-transform: translateX(-50%);
    transform: translateX(-50%);
    bottom: -4px;
    z-index: -1;
    border-radius: 50px;
  }
}