It's supposed to be the css for the page

<title>Untitled Document</title>
<link href="../mypets/thrColHybHdr.css" rel="stylesheet" type="text/css" />
<!--[if IE]>
<style type="text/css">
/* place css fixes for all versions of IE in this conditional comment */
.thrColHybHdr #sidebar1, .thrColHybHdr #sidebar2 { padding-top: 30px; }
.thrColHybHdr #mainContent { zoom: 1; padding-top: 15px; }
/* the above proprietary zoom property gives IE the hasLayout it needs to
avoid several bugs */
</style>
<![endif]--><style type="text/css">
<!--

When I run the browser compatibility report, it tells me this:
Found 1 errors in external css files

Affects: Firefox 2.0; Internet Explorer 5.0, 5.5, 6.0, 7.0; Internet Explorer
for Macintosh 5.2; Netscape 8.0; Opera 8.0, 9.0; Safari 2.0