html代码显示不出来

Question

下面这段代码，CSS没写什么别的，但就是浏览器屏幕缩小后就不显示了，求教是咋回事

 <div class="article-text-page-2 col-md-8 col-md-offset-2">
                <span class="glyphicon glyphicon-menu-left">
                  <a href=""></a>
                </span>
               <span class="glyphicon glyphicon-arrow-down "></span>&nbsp;
               <span class="glyphicon glyphicon-menu-right">
                <a href=""></a>
                </span>
              </div>

Answer 1

媒体查询里写了隐藏吧