How To Use IDs to Override Classes? - CSS Tutorials - Introduction To CSS Basics

Class is a nice way to separate a group of tag instances. To identify one or two special instances, you can use the ID attributes and ID selectors. In the CSS example below, the ID selector "P#hot" wins over all other selectors, so the third row in the table will be in red:

<html><head>
<title>CSS Included</title>
<style type="text/css">
  /* matches P instances with id="hot" only */
  P#hot {color: red}

  /* matches P instances with class="url" only */
  P.url {margin-top: 0px; margin-left: 20px; 
    font-family: sans-serif; fond-weight: bold}

  /* matches P instances inside TABLE only */
  TABLE P {margin-top: 0px; margin-left: 40px; 
    font-family: serif; font-size: 12pt; color: blue}

  /* matches all instances of tag P */
  P {font-family: arial; font-size: 14pt; color: black}
</style>
</head><body>
<p>Welcome to FYICenter.com resource listings:<br> 
<table>
<tr><td><p class="url">www.w3.org</p></td>
  <td><p>W3 home page.<p></td></tr>
<tr><td><p class="url">www.php.net</p></td>
  <td><p>PHP home page.<p></td></tr>
<tr><td><p class="url" id="hot">www.google.com</p></td>
  <td><p id="hot">Google search.<p></td></tr>
</table>
</body></html>