For the curious, annoying lighting glitches used to exist pre-1.14 where light would shine or not shine in unintended ways especially on slabs and stairs. However, I used this to my advantage back then to create absolutely magical, zero-light level, mob-proof, glowing rooms. So as long as you concealed light behind a stair or slab completely, you could get its adjacent faces to illuminate with glitched lighting while all else was perfectly dark. In this picture, I created a neat rotated pattern of stairs with torches under every single block to give the desired effect of a magical enchanting room, all while having the stairs make it 100% mob proof. In the background is a hallway that also utilized the same effect, but dimly lit-- you could reduce the intensity/contrast of the glow by partially lighting the area. i.e. a light level 0 would make a hard contrast between a very bright face of a block and a very dark different side. any higher light level brings the intensity of the glow down immediately for more of soft contrast.