Dark Mode
Noun · Slang & Abbreviations
Definitions
Dark Mode is a display setting that uses light-colored text, icons, and interface elements on a dark background, inverting the traditional light-mode design of dark content on a white background. Dark mode has become a standard feature across operating systems (iOS, Android, Windows, macOS), web browsers, and applications. Proponents cite benefits including reduced eye strain in low-light environments, lower power consumption on OLED and AMOLED screens (where black pixels are truly off), improved readability for some users, and aesthetic preference. However, research on readability is mixed: dark text on light backgrounds tends to be more readable in well-lit environments. Implementing dark mode in web development involves CSS media queries (prefers-color-scheme), CSS custom properties for theme colors, and careful attention to contrast ratios to maintain accessibility. The feature requires designing two complete color systems and testing all interface elements in both modes. Dark mode gained mainstream popularity around 2018-2019 when major platforms adopted it.
In plain English: A display setting that makes backgrounds dark and text light — easier on the eyes at night and a strong opinion in every developer's heart.
The accessibility implications of dark mode are nuanced: it helps users with light sensitivity and some forms of visual impairment, but can be harder to read for users with astigmatism (about 50% of the population). Good implementations offer both options and respect the OS-level preference.
Example: 'We added dark mode support with CSS prefers-color-scheme media query. Took 2 hours for the basic implementation and 2 weeks to get the edge cases right.'
Source: accessibility nuance
Origin Story
The oldest display mode that became the newest design trend
Early computer terminals — the VT100, the ADM-3A, the IBM 3270 — displayed **light text on dark backgrounds** by default. This wasn't a design choice; it was how CRT phosphors worked. Light mode (dark text on a white background) arrived with the Xerox Alto and Apple Lisa in the 1970s and 1980s, mimicking paper. For decades, white backgrounds dominated.
Dark mode's revival began in developer tools (code editors had always offered dark themes) and accelerated with smartphone OLED displays, where dark pixels are literally turned off, saving battery. Apple added system-wide dark mode to macOS Mojave (2018) and iOS 13 (2019). Google followed with Android 10 (2019). The feature became one of the most requested across all platforms.
The health claims around dark mode are debated. Some studies suggest it reduces eye strain in low-light environments; others found that light mode is actually easier to read for most people in well-lit rooms. What's not debated is its popularity — surveys consistently show 80%+ of developers prefer dark mode.
Coined by: Historical display technology; modern revival led by Apple/Google
Context: CRT terminals, 1970s; modern revival, 2018-2019
Fun fact: The term 'dark mode' as a toggle feature was popularized by Twitter's 2016 'Night Mode.' Before that, apps typically called it 'night mode,' 'dark theme,' or just had it buried in settings. Twitter's prominent implementation helped standardize both the name and the expectation.