A Blue is a configurable site framework that gathers pages from the Portal and elsewhere into one branded hub, with access controlled per page. A Light Blue you configure yourself, while a Full Blue adds components custom-coded by mWater.
Video: Blues - Custom Websites on YouTube
Ministers and the general public will not learn a data platform's navigation, and there is no reason they should have to. A programme hub that opens on the two dashboards that matter, with the guidance beside them, gets used. A link into a Portal with a sidebar of ninety items does not. The underlying data does not move, only the way people arrive at it.