Drupal 7: add CSS files to certain nodes in template.php

template.php

function pj_preprocess_page(&$variables, $hook) {
    //ADD TESTICULAR CANCER CSS TO FRONT PAGE 
    if (drupal_is_front_page()) {
    	drupal_add_css(drupal_get_path('theme', 'pj') . '/css/tc.css', array('group' => CSS_THEME, 'type' => 'file'));
    }

    // When this goes through the theme.inc some where it changes _ to - so the tpl name is actually page--type-typename.tpl
    if (isset($variables['node'])) {
        $variables['theme_hook_suggestions'][] = 'page__type__'. str_replace('_', '--', $variables['node']->type); 
        
        //ADD TESTICULAR CANCER CSS TO BLOG POST
	    if ($variables['node']->nid == 24) {
	    	drupal_add_css(drupal_get_path('theme', 'pj') . '/css/tc.css', array('group' => CSS_THEME, 'type' => 'file'));
	    }
    } 
       
}