@collab-ui/core/scss/components/collapse-button/examples/collapsed.html

Cisco Collab UI CSS Framework

<button
  class="cui-button cui-button--36 cui-collapse-button cui-collapse-button--left"
  alt="expand"
  type="button"
  aria-label="expand"
  tabindex="0"
>
  <span class="cui-button__children" style="opacity: 1;">
    <i
      class="cui-icon icon icon-panel-control-right_12"
      style="font-size: 12px;"
    ></i>
  </span>
</button>