class="col-lg-4 col-sm-4 col-12">
            <div class="form-group">
              <label for="opacity">Opacity</label>
              <br>
              <input type="text" id="opacity" class="form-control demo" data-opacity=".5" value="#766fa8">
              <span class="help-block">
                Opacity can be assigned by including the <code>data-opacity</code>
                attribute or by setting the <code>opacity</code> option to
                <code>true</code>.
              </span>
         