Dark interfaces predate light ones. Early CRTs displayed green or amber phosphor text on black — the original "dark mode" was just how screens worked. The Xerox Alto and Apple Macintosh introduced the white-page metaphor in the 1980s, and for three decades, light backgrounds became synonymous with computing itself.
The return began quietly. Code editors never fully abandoned dark themes — Sublime Text's Monokai, Atom's One Dark, and VS Code's defaults kept the tradition alive among developers. But the mainstream pivot came in 2018–19 when Apple shipped system-wide dark mode in macOS Mojave and iOS 13, followed immediately by Google's Android 10. Overnight, dark mode went from developer preference to consumer expectation.
The design challenge was harder than it looked. Simply inverting colors produced interfaces that were harsh, illegible, or flat. Apple and Google both published extensive guidance: use dark grays instead of pure black, reduce color saturation, communicate elevation through lighter surfaces rather than darker shadows. Material Design introduced "dark surface" overlays — semi-transparent white layers whose opacity increases with elevation. The result was a new design language that respected the physics of light on screens rather than treating dark mode as a simple CSS filter.