Doctype positioning that breaks css issue

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<?php
/*
 * doctype_test.php
 *
 * Copyright 2014 Benjamín Ariel Nava Martínez <arielnmz@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301, USA.
 *
 *
 */

echo 'This is some text echoed before the doctype';

?>

<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">

<head>
    <title>sin título</title>
    <meta http-equiv="content-type" content="text/html;charset=utf-8" />
    <meta name="generator" content="Geany 1.24.1" />
    <style>
    body {
        background: #333;
        font-size: 10pt;
        color: white;
        font-family: sans;
    }
    #Table {
<!--
        font-size: inherit;
-->
    }
    </style>
</head>

<body>
    <table id="Table"><tr><td>This is some text in the table</td></tr></table>
</body>

</html>