title: IE7 & IE8 don't apply CSS to HTML5
body: <p>I've been struggling to get HTML5 tags to work on IE7 &amp; IE8. Finally I have used html5shiv.js and the problem was solved. The elements displays on screen as they are displayed on any modern browser.</p>
  
  <p>But for now, I don't know why IE7 &amp; IE8 won't apply the css rules I have declared. For example:</p>
  
  <pre><code>header
  {
      background-color: #000000;
  }
  </code></pre>
  
  <p>Does not apply black background color to the header tag nor any background color. When I search for that declarations on IE7 &amp; IE8 it appears to be undeclared, but when I try IE on IE9 mode, that same css rule I have declared do appear and styles the element with black background color. Any help or solutions will be really appreciated.</p>