title: What is the difference between pseudo-classes and pseudo-elements?
body: <p>What is the difference between <code>div::after {}</code> and <code>div:after {}</code> ? When do we have to use <code>::</code> over <code>:</code>?</p>
  <blockquote>
  <p>Double colon and single-colon notation is to distinguish between
  pseudo-classes and pseudo-elements.</p>
  </blockquote>
  <p>What is the actual meaning of the above statement?</p>