The most important aspect of this project is the design of the box and the notebook. Overall, the app will have a wooden theme, and it's goal is to give the user the impression that they are working with beautifully crafted boxes which they have created. Once a box is selected. They should feel like they are interacting and working inside the box they have chosen.
Colors should be conservative yet beautiful. Ultimately, the user will be able to choose between several different box woods and notebook colors to add variety.
For the boxes, think of woods like oak, mahogany, cedar, blackwood, etc.
For notebooks, colors should be complementary to the boxes. Think dark blues, blacks, grays, etc