Mac-native design — the Liquid Glass era

AI design tools don't have enough context on what a real Mac app looks like, so their output drifts toward web dashboards and iOS ports. This skill is that missing context. Sourced from Apple's HIG (macOS 26 "Tahoe"), Apple's "Adopting Liquid Glass" guide, and community Mac-native references (see references/).

1. The core mental model — two layers

Liquid Glass splits every interface into exactly two layers:

1. Content layer — documents, lists, media, canvases. Opaque or standard materials. What the app is about.
2. Floating glass layer — controls and navigation (toolbars, sidebars, tab bars, menus, popovers) that float above content on the Liquid Glass material.