select2/docs/_sass/_alert.scss

// Alerts
//
// Modify Bootstrap's default alert styles to mimick
// the `.bs-callout` styles from Bootstrap's docs.
//
// @see https://github.com/twbs/bootstrap/blob/master/docs/assets/css/src/docs.css#L711
// @see https://github.com/twbs/bootstrap/blob/master/less/alerts.less

.alert {
  background: #fff;
  border: 1px solid #eee;
  border-left-width: 5px;
  border-radius: 3px;
  color: #333;
  margin: 20px 0;
  padding: 20px;

  h4 {
    font-size: 18px;
    margin-top: 0;
    margin-bottom: 5px;
  }

  &-danger {
    border-left-color: #ce4844;

    h4 {
      color: #ce4844;
    }
  }

  &-info {
    border-left-color: #1b809e;

    h4 {
      color: #1b809e;
    }
  }

  &-warning {
    border-left-color: #aa6708;

    h4 {
      color: #aa6708;
    }
  }
}