Midcentury Modern. If we started off by painting everything white this shows that your desks (and chairs) would look good. You could then go for a dark or light floor with painted boards or a floor covering and introduce colour to the walls with property displays in individual photo frames.
In addition to their intrinsic beauty, tile roofs are extremely durable, lasting for centuries in some cases. Whether made of clay or concrete (the latter is more colorfast), individual tiles are often molded in barrel shapes for interlocking installation. Weight will be an issue, so be sure ask a structural engineer if your roof framing will support a tile application.