title: position fixed header in html
body: <p>I have a header (dynamic height) with a fixed position.</p>
  <p>I need to place the container div right below the header. As the header height is dynamic, I can't use the fixed value for top margin.</p>
  <p>How can this be done?</p>
  <p>Here's my CSS:</p>
  <pre><code>#header-wrap {
      position: fixed;
      height: auto;
      width: 100%;
      z-index: 100
  }
  #container{ 
      /*Need to write css to start this div below the fixed header without mentioning top margin/paading*/
  }
  </code></pre>
  <p>...and HTML:</p>
  <pre><code>&lt;div id=&quot;header-wrap&quot;&gt;
    &lt;div id=&quot;header&quot;&gt;
      &lt;div id=&quot;menu&quot;&gt;
        &lt;ul&gt;
        &lt;li&gt;&lt;a href=&quot;#&quot; class=&quot;active&quot;&gt;test 0&lt;/a&gt;&lt;/li&gt;
        &lt;li&gt;&lt;a href=&quot;#&quot;&gt;Give Me &lt;br /&gt;test&lt;/a&gt;&lt;/li&gt;
        &lt;li&gt;&lt;a href=&quot;#&quot;&gt;My &lt;br /&gt;test 2&lt;/a&gt;&lt;/li&gt;
        &lt;li&gt;&lt;a href=&quot;#&quot;&gt;test 4&lt;/a&gt;&lt;/li&gt; 
        &lt;/ul&gt;
      &lt;/div&gt;
      &lt;div class=&quot;clear&quot;&gt;
      &lt;/div&gt;
    &lt;/div&gt;
  &lt;/div&gt;&lt;!-- End of header --&gt;
  
  &lt;div id=&quot;container&quot;&gt;
  &lt;/div&gt;
  </code></pre>