Aqua

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! class="ios-lab" | Developer
| class="ios-val" | [[Apple]]
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! class="ios-lab" | Introduced
| class="ios-val" | January 2000 (Macworld) · shipped with Mac OS X (2001)
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! class="ios-lab" | Type
| class="ios-val" | [[macOS]] design language
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! class="ios-lab" | Succeeded by
| class="ios-val" | [[Liquid Glass]] ([[macOS Tahoe]], 2025)
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Aqua was the face of Mac OS X for a quarter century — the water-themed design language [[Steve Jobs]] unveiled with the promise that "we made the buttons on the screen look so good you'll want to lick them." Gel-like buttons, pinstripes, drop shadows, and the genie effect announced that the [[Mac]]'s NeXT-based rebirth would look as new as it was.

= Evolution =

Aqua never stood still: the candy gels gave way to brushed metal, then to the unified gray of the late 2000s; OS X Yosemite (2014) flattened it in [[iOS]] 7's image; macOS Big Sur (2020) rounded and lightened everything toward iPad idioms. The name outlived most of its original pixels — officially, every macOS appearance from 10.0 through the mid-2020s was still "Aqua."

= Position =

Aqua set the template for consumer OS design in the 2000s and defined the Mac's personality through four processor architectures. Its era closed when [[Liquid Glass]] arrived with [[macOS Tahoe]] — the first design language since 2001 to replace, rather than renovate, what Aqua began.