                <p>
                            You can indicate invalid and valid form fields with
                            <code>.is-invalid</code> and <code>.is-valid</code>.
                            Note that <code>.invalid-feedback</code> is also
                            supported with these classes.
                          </p>
                        </div>
                        <div class="col-sm-6">
                          <label for="valid-state">Valid State</label>
                