Guide on How to Load CSS File Per Role
Add the next code to you template.php

/**
 * Implement hook_preprocess_page().
 */
function THEME_NAME_preprocess_page(&amp;$variables) {
  global $user;

  if (in_array('DESIRED_ROLE', $user-&gt;roles)) {
    drupal_add_css(drupal_get_path('theme', 'THEME_NAME') . '/YOUR_CSS_NAME.css');
  }
}