くの字の矢印 (下向き)のアイコン

<span class="dli-chevron-down"></span>

.dli-chevron-down {
  display: inline-block;
  vertical-align: middle;
  color: #333;
  line-height: 1;
  width: 1em;
  height: 1em;
  border: 0.1em solid currentColor;
  border-left: 0;
  border-bottom: 0;
  box-sizing: border-box;
  transform: translateY(-25%) rotate(135deg);
}