Font Awesome icon size not increasing

Question

I have Font Awesome icons installed on this site. The icons size isn't increasing even after adding the class to increase size.

<ul class="stay-connected-inner list-inline">
  <li><a href="#"><i class="fa fa-twitter fa-3" aria-hidden="true"></i></a></li>
  <li><a href="#"><i class="fa fa-linkedin fa-3" aria-hidden="true"></i></a></li>
  <li><a href="#"><i class="fa fa-medium fa-3" aria-hidden="true"></i></a></li>
  <li><a href="#"><i class="fa fa-linkedin fa-3" aria-hidden="true"></i></a></li>
</ul>

Answer 1

To increase icon sizes relative to their container, use the fa-lg (33% increase), fa-2x, fa-3x, fa-4x, or fa-5x classes.

            <ul class="stay-connected-inner list-inline">
              <li><a href="#"><i class="fa fa-twitter fa-3x" aria-hidden="true"></i></a></li>
              <li><a href="#"><i class="fa fa-linkedin fa-3x" aria-hidden="true"></i></a></li>
              <li><a href="#"><i class="fa fa-medium fa-3x" aria-hidden="true"></i></a></li>
              <li><a href="#"><i class="fa fa-linkedin fa-3x" aria-hidden="true"></i></a></li>
            </ul>