Is there a design guide on how solidus arrived with the component layout? It's very intricate and really interesting to go through. https://github.com/solidusio/solidus/tree/main/admin/app/components/solidus_admin

No, I don’t believe so. I think it was primarily a way to maximize reuse and thus allow extensions to be as full featured as possible by building off it. Hopefully it works well. I like it so far.

There’s no design guide at the moment. I think the design will keep evolving as we keep adding pieces to the admin, it’s not final. As Jared mentioned, we tried to always keep in mind the limitations of the old admin, a component-based architecture might help avoiding too many customizations (eg using deface) when people want to create extensions or custom pieces of the admin.