newbie jquery user: pointing to an external style sheet

newbie jquery user: pointing to an external style sheet

i am trying to change the following code to work with my site:
<script type="text/javascript" language="javascript" src="jquery-1.2.2.pack.js"></script>
<script type="text/javascript" language="javascript">
$(document).ready(function(){
  // Reset Font Size
  var originalFontSize = $('html').css('font-size');
  $(".resetFont").click(function(){
  $('html').css('font-size', originalFontSize);
  });
  // Increase Font Size
  $(".increaseFont").click(function(){
     var currentFontSize = $('html').css('font-size');
   var currentFontSizeNum = parseFloat(currentFontSize, 10);
    var newFontSize = currentFontSizeNum*1.2;
   $('html').css('font-size', newFontSize);
   return false;
  });
  // Decrease Font Size
  $(".decreaseFont").click(function(){
     var currentFontSize = $('html').css('font-size');
   var currentFontSizeNum = parseFloat(currentFontSize, 10);
    var newFontSize = currentFontSizeNum*0.8;
   $('html').css('font-size', newFontSize);
   return false;
  });
});
</script>


.css I assume refers to internal (on the current page) css since the site example has no external .css

My question: How do you point to an external style sheet???

Thanks.