I would like to create a notebook with questions that have attached hints and answers. The hints and answers should be hidden, but the display should clearly indicate (e.g., with a button) that each can be expanded whenever the user desires.
As an example of a fairly ugly solution, one can put the question in a text cell followed by a text cell that provides a hint header, saying only "open for hint". The hint header cell would then be grouped with subsequent cells, we would make a cell group out of the bunch, and show the group opener. The same thing could be done for the answer. This is perhaps not horrible, but the group opener is a bit subtle, and changing style across the notebook would not be easy. (Well ... perhaps tags?) I'm looking for a better solution, especially one someone is already using with their students.