Using Marker to add a Triangle to List Items

HTML

<ul class="triangle-list">
  <li>List Item 1</li>
  <li>List Item 2</li>
  <li>List Item 3</li>  
</ul>

CSS

ul.triangle-list {
  margin: 0.75em 0;
  padding: 0 1em;
  list-style: none;
}
ul.triangle-list li::marker {
  content: "▶ ";
}