Passing individual values like name or author to child components whould make the code less maintainable as requirements in data might change, but passing a dynamic list of which you'd have to remember the keys or reference the json document adds needless overhead, so instead I defined a data structure appropriate for this test.
Mixing styling and logic is only a good idea if the logic depends on the styling or vice versa. This way specific styling can be edited fast and without much hassle.
Handling errors directly in the main code make it less legible.
The details page is rendered based on a predefined data structure, which makes it accessible to any caller that has access to such a data structure.
Classes with a PageView suffix are responsible for the actual page view, while the ones with just Page handle the logic and the appbar of that page so it is possible to understand what a class roughly does.
Comments are used sparcely and mainly to summorize larger blocks of code, since the code is written in a readable and human-parsable way.
3 hours (which includes this write up) with no prior knowledge of the dart programming language.