title: Why margin:auto doesn't work?
body: <p>I want to center my element but when I use </p>
  
  <pre><code>margin-left: auto;
  margin-right: auto;
  </code></pre>
  
  <p>it doesn't work!</p>
  
  <p>this is my html</p>
  
  <pre><code>&lt;section id="t"&gt;
      &lt;article class="tc"&gt;Hi&lt;/article&gt;
      &lt;article class="tc"&gt;Hi agian!&lt;/article&gt;
  &lt;/section&gt;
  </code></pre>
  
  <p>and this is my css:</p>
  
  <pre><code>#t {
      margin-left: auto;
      margin-right: auto;
      margin-top:10px;
  }
  .tc {
      margin-left: auto;
      margin-right: auto;
      width: 600px;
      display: inline;
      border-style: solid;
      border-width:1px;
  }
  </code></pre>
  
  <p>and you can see the result <a href="http://jsfiddle.net/ahmadalli/2sagZ/5/">here</a>.</p>
  
  <p>Can anybody help me?</p>