横向模式和纵向模式下的html5移动应用程序

Question

我使用bootstrap 3.3设计了一个html5安卓应用程序，我在纵向模式下显示12 col

COL-XS-12

<div class="col-xs-12 col-xs-6">
  <div class="panel panel-card">
    <div class="item">
      <div class="bottom text-white p">
        Title
      </div>
    </div>
    <div class="p">
      <h3>Paracosm</h3>
      <p>
        The titles of Washed Out's breakthrough song and the first single from Paracosm share the
        two most important words in Ernest Greene's musical language: feel it. It's a simple request, as well...
      </p>
    </div>
  </div>
</div>

我想在横向模式下显示6 col如何做到这一点..

COL-XS-6