Replace Line 1-5 in header.php
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
.......
with:
<!DOCTYPE html>
<?php
$templateURI = get_template_directory_uri();
$homeURL = get_home_url(); ?>
<html <?php language_attributes(); ?>>
The old long definition is not needed anymore and causes quirk mode. Should have been removed since IE4 is dead. Recently google started complaining about it so I noticed and changed it.