三角の矢印 (左向き)のアイコン

<span class="dli-caret-left"></span>

.dli-caret-left {
  display: inline-block;
  vertical-align: middle;
  color: #333;
  line-height: 1;
  width: 0;
  height: 0;
  border-style: solid;
  border-color: transparent;
  border-width: 0.375em 0.64952em;
  border-right-color: currentColor;
  border-left: 0;
}