Set empty design layout for a controller

Question

I've created a controller that is displaying some html code retrieved from orders.phtml file :

<?php
class Envato_RecentProducts_OrderController extends Mage_Core_Controller_Front_Action
{
    public function indexAction()
    {
        echo $this->getLayout()->createBlock('core/template')->setTemplate('newaves/orders.phtml')->toHtml();
    }
}

I usually create pages using CMS with selecting Empty layout in Design section, that way I have css theme classes imported in that page even if the page is empty:

That code retrieves the header and footer, it doesn't help as I only want an empty page :

$this->loadLayout();
$this->renderLayout();

How can I have the controller 'imports' the default theme/ css classes ?