title: <th> text-align compatibility
body: <p>In a table heading, the default text alignment for the <code>th</code> tag is center.</p>
  
  <p>Consider the following code:</p>
  
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;html&gt;
      &lt;head&gt;
          &lt;style type="text/css"&gt;
              body {
                  background-color: aliceblue;
              }
              .default_grid {
                  text-align: left;
                  width: 600px;
                  color: white;
              }
                  .default_grid th {
                      /*  text-align: left;  */
                  }
                  .default_grid .first {
                      background-color: purple;
                  }
                  .default_grid .second {
                      background-color: orange;
                  }
          &lt;/style&gt;
      &lt;/head&gt;
      &lt;body&gt;
          &lt;table class="default_grid"&gt;
              &lt;thead&gt;
                  &lt;tr&gt;
                      &lt;th class="first"&gt;Test One&lt;/th&gt;
                      &lt;th class="second"&gt;Test Two&lt;/th&gt;
                  &lt;/tr&gt;
              &lt;/thead&gt;
          &lt;/table&gt;
      &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>In Firefox, <a href="http://en.wikipedia.org/wiki/Internet_Explorer_7" rel="nofollow">Internet&nbsp;Explorer&nbsp;7</a> (&amp; lower), Safari, Chrome and <a href="http://en.wikipedia.org/wiki/Opera_%28web_browser%29" rel="nofollow">Opera</a> the text in &lt;th> is aligned left. While in <a href="http://en.wikipedia.org/wiki/Internet_Explorer_8" rel="nofollow">Internet&nbsp;Explorer&nbsp;8</a> and <a href="http://en.wikipedia.org/wiki/Internet_Explorer_9" rel="nofollow">Internet&nbsp;Explorer&nbsp;9</a>, the text is aligned center unless the rule is specified directly on &lt;th> tag (uncomment line# 14).</p>
  
  <p>Which one is the correct behavior?</p>