CodePen Embed - wjNzWO

<h1>This is a heading</h1>
<p>The ::before pseudo-element inserts content before the content of an element.</p>

h1 {
  position: relative;
  padding-left: 20px;
}
h1::before {
  position: absolute;
  content: "";
  left: 0;
  top: 8px;
  border-top: 10px solid transparent;
  border-bottom: 10px solid transparent;
  border-left: 10px solid green;
}

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