Common.css

Note: After saving, you may have to bypass your browser's cache to see the changes.

• Firefox / Safari: Hold Shift while clicking Reload, or press either Ctrl-F5 or Ctrl-R (⌘-R on a Mac)
• Google Chrome: Press Ctrl-Shift-R (⌘-Shift-R on a Mac)
• Internet Explorer: Hold Ctrl while clicking Refresh, or press Ctrl-F5
• Opera: Go to Menu → Settings (Opera → Preferences on a Mac) and then to Privacy & security → Clear browsing data → Cached images and files.

/* CSS placed here will be applied to all skins */

 #ca-talk { display: none !important; }
 #ca-viewsource { display: none !important; }

<?php global $wgUser; if( !$wgUser->isAllowed('edit') ) { ?>

     <style type="text/css">
       #ca-watch { display: none !important; }
     </style> 
   <?php } ?>