wagtail/client/scss/components/_breadcrumbs.scss

.w-breadcrumbs:not(.editor-view .w-breadcrumbs) {
  @apply sm:w-py-2.5;

  li[hidden] ~ li:last-child,
  li:only-child {
    a {
      font-size: theme('fontSize.18');
      font-weight: theme('fontWeight.extrabold');

      @include media-breakpoint-up(md) {
        font-size: theme('fontSize.22');
      }
    }

    .w-breadcrumbs__sublabel,
    .w-breadcrumbs__icon {
      display: inline-block;
    }

    .w-breadcrumbs__icon {
      width: theme('spacing.5');
      height: theme('spacing.5');
      margin-inline-end: theme('spacing[2.5]');
    }
  }
}