title: Unable to center div on bootstrap 3
body: <p>I'm unable to center a lot of div since I upgrade my bootstrap from 2.1 to 3.0</p>
  
  <p>For example with this code:</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;div id="center" class="container"&gt;
      &lt;div class="row"&gt;
          &lt;div class="btn-toolbar"&gt;
              &lt;div class="btn-group"&gt;
                  &lt;a class="btn btn-default" href="#"&gt;test&lt;/a&gt;
              &lt;/div&gt;
          &lt;/div&gt;
  
          &lt;br /&gt;
  
          &lt;p&gt;Am I centered ?&lt;/p&gt;
          &lt;a class="btn btn-default" href="#"&gt;Back&lt;/a&gt;
      &lt;/div&gt;
  
  &lt;/div&gt;
  </code></pre>
  
  <p>I had this rule:</p>
  
  <pre><code>#center {
      margin: 0 auto;
  }
  </code></pre>
  
  <p>But the result is:
  <img src="https://i.stack.imgur.com/QYs99.png" alt="enter image description here"></p>
  
  <p>Or another example, how to center this:</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;div id="center" class="container"&gt;
      &lt;div class="row"&gt;
          &lt;li class="col-md-5"&gt;
              &lt;ul class="list-unstyled"&gt;
                  &lt;li&gt;&lt;i class="icon-user"&gt;&lt;/i&gt; aaaaaaaaa&lt;/li&gt;
                  &lt;li&gt;&lt;i class="icon-envelope"&gt;&lt;/i&gt; bbbbbbbbbb&lt;/li&gt;
                  &lt;li&gt;&lt;i class="icon-envelopebug"&gt;&lt;/i&gt; cccccccccccc&lt;/li&gt;
              &lt;/ul&gt;
          &lt;/li&gt;
          &lt;li class="col-md-5"&gt;
              &lt;ul class="list-unstyled"&gt;
                  &lt;li&gt;&lt;i class="icon-user"&gt;&lt;/i&gt; aaaaaaaaa&lt;/li&gt;
                  &lt;li&gt;&lt;i class="icon-envelope"&gt;&lt;/i&gt; bbbbbbbbbb&lt;/li&gt;
                  &lt;li&gt;&lt;i class="icon-envelopebug"&gt;&lt;/i&gt; cccccccccccc&lt;/li&gt;
              &lt;/ul&gt;
          &lt;/li&gt;
      &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/pROWZ.png" alt="enter image description here"></p>
  
  <p>Thank you for your help</p>