<rules
    xmlns="http://namespaces.plone.org/diazo"
    xmlns:css="http://namespaces.plone.org/diazo/css"
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    >

    <replace
        css:theme="#alpha"
        css:content-children="#one"
        />

    <replace
        css:theme="#beta"
        css:content-children="#two"
        />

    <replace
        css:theme="#delta"
        css:content-children="#three"
        />


</rules>
