The xhtml head template extends the simple head template and provides an additional CSS that helps render the xhtml theme form elements. The contents of head.ftl are:

{snippet:id=all|lang=xml|url=webwork/src/java/template/xhtml/head.ftl}

The contents of styles.css are:

{snippet:id=all|lang=xml|url=webwork/src/java/template/xhtml/styles.css}