Don't want to learn Bootstrap classes? Go to Bootstrap builder for busy developers.

Bootstrap class: .alert-heading

<div class="alert alert-success" role="alert">
  <h4 class="alert-heading">Well done!</h4>
  You successfully read this important alert message.
</div>

Preview

Sass source

/* _alert.scss:14 */
.alert-heading {
  // Specified to prevent conflicts of changing $headings-color
  color: inherit;
}

Uses variables

/* _alert.scss:14 */
$headings-color