Thesis child theme CSS stripping all but child theme

gistfile1.aw

<?php

// Initial sanity check
if (! defined('ABSPATH'))
	die('Please do not directly access this file');

// Bring in the main functions file so we have access to all the yummy Thesis goodness
include_once(TEMPLATEPATH . '/functions.php');

class thesis_responsive_child_theme extends thesis_custom_loop {
		
	public function __construct() {
		parent::__construct();
		add_action('init', array($this, 'init'));
	}
	
	public function init() {
		// actions and filters that will run on init. you could put other things here if you need.
		$this->actions();
		$this->filters();
	}
	
	public function actions() {
		// this will force thesis to generate CSS when the user switches to the child
		add_action('after_switch_theme', 'thesis_generate_css');
	}
	
	public function filters() {		
		// Filter out the standard thesis style.css.
		add_filter('thesis_css', array($this, 'css'), 11, 5);
	}
	
	public function css($contents, $thesis_css, $style, $multisite, $child) {

		// only include the child theme css
		$css = $child;

		// return it
		return $css;
	}
		
}

new thesis_responsive_child_theme;