The OLED constraint
On OLED screens, each pixel produces its own light — pure black (#000000) means a pixel that consumes zero power and emits zero photons. This creates extreme contrast between dark backgrounds and bright text that feels jarring in most UI contexts, despite the technical contrast ratio being ideal (21:1 with white). Apple's dark mode uses #1C1C1E as its primary background rather than true black, using black only for borders, modals, and elevated surface outlines. This surface-layering approach creates depth without the harshness of maximum contrast.
