Bootstrap“glyphicon glyphicon-fullscreen not working”

Question

我已下载gentellela bootstrap模板http://gentelella.yiister.ru/site/timeline#

然后我找到了

<!-- /menu footer buttons -->
                <div class="sidebar-footer hidden-small">
                    <a data-toggle="tooltip" data-placement="top" title="Settings">
                        <span class="glyphicon glyphicon-cog" aria-hidden="true"></span>
                    </a>
                    <a data-toggle="tooltip" data-placement="top" title="FullScreen">
                        <span class="glyphicon glyphicon-fullscreen" aria-hidden="true"></span>
                    </a>
                    <a data-toggle="tooltip" data-placement="top" title="Lock">
                        <span class="glyphicon glyphicon-eye-close" aria-hidden="true"></span>
                    </a>
                    <a data-toggle="tooltip" data-placement="top" title="Logout">
                        <span class="glyphicon glyphicon-off" aria-hidden="true"></span>
                    </a>
                </div>
                <!-- /menu footer buttons -->
            </div>
        </div>

当我点击glyphicon glyphicon-fullscren或glyphicon-cog或glyphicon-eye-close或glyphicon-off的图标时，它们没有显示。我该怎么做才能解决这个问题？为了您的信息，我正在使用Yii 2.0框架。提前致谢