A lighting assembly includes a light guide having opposed major surfaces between which light propagates by total internal reflection and a light input edge. The light assembly also includes a light engine. The light engine has a heat conductive armature having a receptacle for a portion of the light guide that includes the light input edge and a light source retained by and thermally coupled to the armature. The armature functions as a heat sink for dissipating heat generated by the light source. The light guide is mechanically retained in the receptacle, and the light guide and the armature cooperate to align the light input edge with the light source for inputting light from the light source into the light guide through the light input edge.