The relative ease with which Plone’s visual elements can be customized without having to modify Plone’s own source code is one of the greatest advantages in using Plone as a development platform. Broadly speaking, visual elements can come from one of these four different sources:
portal_skinsin the ZMI. Plone’s standard skins are mostly in
CMFPlone/skins, though other packages provide their own skin layers too.
configure.zcmlfile, using a