Lens system configuration of KMT-2018-BLG-1976. The line with an arrow indicates the source trajectory,the two blue dots marked by “host” and “planet” are lens positions, and red figures represent caustics. The dotted circle around the host represents the Einstein ring. The inset shows the zoomed-in view of the central magnification region, in which the gray curves around the position of the host represent equi-magnification contours The upper and lower panels are for the “inner” (close; s < 1.0) and “outer” (wide; s > 1.0) solutions, respectively.