A lighting system includes an upper housing supporting a light engine, and a diffuser coupled to the upper housing. The diffuser may be monolithic, i.e. formed of a single material as a single piece without joints or seams where separate components are joined. The monolithic diffuser may be formed by an additive manufacturing process, for example 3D printing. The diffuser may couple to the upper housing with a tool-less connection. The portion of the tool-less connection defined by the diffuser may be formed by the additive manufacturing process. The lighting system may further include a lens coupled to the diffuser opposite the upper housing with a lens retaining ring. The lens retaining ring may be formed with an additive manufacturing process, and may define an annular snap-fit with the diffuser.