Aqua (user interface)

Aqua is a graphical user interface, design language and visual theme used in Apple's operating systems. It was themed to replicate water, with "droplet-like" components and a heavy use of reflective effects and translucency. Its goal was to "incorporate color, depth, and complex textures into a visually appealing interface" in macOS applications. At its introduction, Steve Jobs noted that "... it's liquid, one of the design goals was when you saw it you wanted to lick it".

Aqua was introduced at the 2000 Macworld conference in San Francisco. It was first released in July with iMovie 2, and with Mac OS X 10.0 the following year. Aqua is the successor to Platinum, which was used in Mac OS 8, Mac OS 9, and developer releases of Rhapsody (including Mac OS X Server 1.0). Apple continually revised Aqua with subsequent operating system revisions, including adding SwiftUI design standards and Swift language support into Aqua’s interface, and implementing its design into newer products such as the iPhone. In 2013, Apple heavily revised the skeuomorphic user interface to adopt a flat design. In 2025, Apple introduced the Liquid Glass design language across their operating systems.