Because gears appear as parts of a portal page (and more specifically, within an HTML table cell), you should not treat the HTML tags for the gear as you would for a freestanding HTML page. Because they would be redundant, you should not use the following HTML tags within your gear page documents:
<html></html>
<header></header>
<body></body>
<title></title>
<meta></meta>
<frameset></frameset>