I am teaching myself Drupal 9 and I see that the Claro theme is defined as a "Drupal administration theme" while Olivero is defined as a "Drupal front-end theme." Are these complementary themes? I'm not sure about whether I should install both - to have both a front-end and an administration theme or whether I need only one or the other. Any help you might offer in understanding the difference between a "front-end theme" and an "administration theme" would be appreciated.
In the early days, Drupal had a single theme, which was used for both front-end presentation as well as backend content and configuration editing.
Nowadays, there is a rather clear separation between frontend and backend parts of Drupal, and using an admin theme allows to provide a clear and, ideally, easy configuration and editing space for users with backend access. So especially for more complex sites, using different themes for frontend and backend makes it possible to have a fancy frontend that caters to the needs of the (public) users, while also having a functional and optimised backend experience for administrators, editors, or whatever functional role your site might provide.
Whether you need that separation is purely up to you to decide. I would not use a single theme anymore on any of the projects I work on. There are just too many advantages from my point of view.
You might just want to install both, and play a bit around with it, then deactivating the backend theme and see the difference.
Thank you. Your answer provides me with the history and context I was missing.– thornleyNov 13, 2021 at 22:58