Flat Design

In June 2013, at its Worldwide Developers Conference, Apple unveiled iOS 7. The reaction was immediate and loud, because the change was the most violent visual break in the history of the iPhone. Every texture was gone. The leather, the felt, the brushed metal, the green casino baize, the glossy three-dimensional buttons — all of it deleted in a single release. In its place: flat fields of bright color, hairline-weight typography, simple geometric icons, and an enormous amount of white space. A great many people hated it at first. Within two years, it was simply what software looked like, everywhere, on every platform — and it largely still is.

Flat Design did not originate with Apple, and it is important to say so, because the iOS 7 moment is so dramatic that it tends to absorb the whole story. The movement had been building for several years, and its most coherent early statement came from Microsoft. Beginning around 2010, with the Windows Phone 7 interface and the design language Microsoft initially called "Metro," a team in Redmond had been arguing — explicitly, in published design principles — that digital interfaces should stop imitating physical objects. The Metro design principles spoke of being "authentically digital," of typography as the primary design element, of content over chrome. Windows Phone was a commercial failure, but its design language was prophetic. When Apple flattened iOS three years later, it was, in a sense, conceding an argument Microsoft had made first.

The philosophical core of Flat Design is a claim about honesty. Skeuomorphism, the movement it overthrew, had built interfaces that pretended to be physical objects — pretended to be leather, pretended to be paper, pretended to have depth and weight and shadow. Flat Design's argument was that this pretense was, by 2013, both unnecessary and dishonest. Unnecessary, because the population had finished learning the touchscreen and no longer needed the physical metaphors as a teaching aid. Dishonest, because a screen is not a physical object. A screen is a flat, backlit, luminous surface, and an interface that is true to its medium should look like what it is: flat shapes on a lit plane. This is not a new argument. It is, almost word for word, the argument modernism had been making since the 1920s — that a thing should be honest about its material and its function, that it should not dress up as something it is not. Flat Design is modernism's claim, finally applied to the screen.

And the lineage there is direct, not metaphorical. Flat Design is the most recent inheritor of the longest and most powerful lineage in this entire publication. It descends from Swiss design — the grid, the sans-serif type doing the work of hierarchy, the disciplined whitespace, the restraint. Swiss design descends from the Bauhaus, which taught that form follows function and ornament is a kind of lie. The Bauhaus drew on De Stijl and Suprematism, on Mondrian's grammar and Malevich's geometric purity. A flat-design app in 2013 — solid color fields, geometric icons, sans-serif type, no decoration — is, formally, recognizably, a descendant of a black square hung in a corner in Petrograd in 1915. The whole hundred-year argument of modernist design arrives, through this movement, on the screen of every phone on earth.

It was not, however, an unqualified success, and the honest version of this essay has to say so. The first eighteen months of Flat Design produced a genuine, documented usability crisis. In stripping out every bevel, every shadow, every gradient, designers had also stripped out the visual cues that told users what was interactive. A skeuomorphic button looked raised, and raised things can be pressed; a flat rectangle of color looked like — a flat rectangle of color. Users could not tell what was a button, what was a label, and what was a tappable link. The problem was severe enough to get a name in the usability literature: the "flat design usability crisis." Designers had pursued visual honesty so hard that they had sacrificed affordance — the quality that lets a user perceive, on sight, what an element does. It was a real failure, and it had a real consequence: the next movement, Material Design, was created in significant part to fix it.

What emerged from that correction is sometimes called "flat 2.0" or "almost flat" — a Flat Design that quietly readmitted the minimum depth necessary for usability. A subtle shadow returned beneath the floating button. A faint layering came back to indicate what sat above what. The pendulum, having swung to absolute flatness in 2013, settled a little way back toward depth — not the rendered leather of skeuomorphism, but just enough shadow to answer the question "can I tap this?" This settled position is, more or less, where mainstream interface design has remained ever since.

The legacy of Flat Design is hard to overstate precisely because it is hard to see. It won so completely that it became invisible. When a movement is genuinely dominant, people stop perceiving it as a style and start perceiving it as simply the way things are — and that is exactly what has happened here. A person who opens almost any app, almost any website, almost any operating system in the 2020s is looking at Flat Design, but they do not experience it as a choice, an aesthetic, a movement with a history and an argument. They experience it as the neutral, default, obvious appearance of software. That invisibility is the surest possible sign of total victory. Flat Design did to the screen what Swiss design did to the printed page of the corporate twentieth century: it became the unmarked default, the thing you only notice when something deviates from it. The whole modernist project — a century of arguing that honesty and reduction and the grid should govern how things look — achieved, in Flat Design, its largest and quietest triumph.