A fenestration system includes a chassis formed from left and right chassis stiles, and top and bottom chassis rails. The left and right chassis stiles having an outside longitudinal groove, an outside longitudinal ridge, an inside longitudinal groove and an inside longitudinal ridge. The top and bottom chassis rails having an outside longitudinal groove, an outside longitudinal ridge, an inside longitudinal groove and an inside longitudinal ridge. Outside stile covers are configured to engage the longitudinal outside groove and the longitudinal outside ridge of the chassis stile. Inside stile covers are configured to engage the inside longitudinal groove and the inside longitudinal ridge of the chassis stile. Outside rail covers are configured to engage the longitudinal outside groove and the longitudinal outside ridge of the chassis rail. Inside rail covers are configured to engage the inside longitudinal groove and the inside longitudinal ridge of the chassis rail.