bundles/org.eclipse.e4.tools.emf.ui/plugin.xml

<?xml version="1.0" encoding="UTF-8"?>
<?eclipse version="3.4"?>
<plugin>
   <extension
         point="org.eclipse.e4.ui.css.swt.theme">
      <stylesheet
            uri="css/default.css">
      </stylesheet>
   </extension>

</plugin>