.btn-external-accordion::after {
  font-family: 'Font Awesome 5 Pro', sans-serif;
  font-size: 24px;
  padding: 0 6px;
  margin-left: 16px;
  color: var(--subdued);
}

.btn-external-accordion[aria-expanded='false']::after {
  /* plus */
  content: '\f067';
}

.btn-external-accordion[aria-expanded='true']::after {
  /* minus */
  content: '\f068';
}