In GeoNetwork Enterprise a skin called 'minimal' is available to replace the default GeoNetwork look and feel.
You can quickly try the skin by adding ?view=minimal on the url, just before '#'. To activate the skin, go to Admin > Settings and set the view parameter to 'minimal'.
Furthermore, GeoNetwork Enterprise can be installed with the 'dutch' skin, specially developed for the Dutch users. It can come pre-installed with Dutch templates and projection.
In a next step you can further personalise your instance of GeoNetwork in the layout, CSS and logo panels, where you can configure languages, panel-templates, map layers, projections, a background image, menu-bar colours, logo's and many more.