Overleaf/services/web/frontend/stylesheets/components/recurly.scss

.recurly-element-card {
  height: 50px;
  border: 1px solid var(--neutral-60);
  border-radius: var(--border-radius-base);

  &.recurly-element-card-invalid {
    border-color: var(--red-50);
  }
}