Creating Document Level Styles
Document level styles are set in the head of the document. They are enclosed within their own <style></style> tag-pair, like this:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Your document title</title>
<style type="text/css">
styles go here
</style>
</head>
Notice that the opening <style> tag contains a type attribute:
<style type="text/css">