Thank you for your reply.
I tested your example and the text is not render in red color. Therefore, it is not related to the template.
Is it a bug in the corprate version 5.5?
Below, the exact code I am running :
<?php
require_once '../../../Classes/Phpdocx/Create/CreateDocx.inc';
$docx = new Phpdocx\Create\CreateDocx();
$docx->embedHTML('
<html>
<head>
</head>
<body style="color: red">
<p>This is a test.</p>
<p>Another test which must be separated in a specific paragraph.</p>
<p>And another</p>
</body>
</html>');
$docx->createDocx('output');