Apple Design (HIG + Liquid Glass edition)

This skill makes output actually feel Apple — not "generic minimal with more whitespace". The difference lives in specific numbers (type scales, radii, hit targets, easing) and in a philosophy of restraint. Specs here are synthesized from Apple's Human Interface Guidelines as of mid-2026, which means the current Liquid Glass design language, not the pre-2025 flat look.

The one thing to know first: Liquid Glass

Since 2025, Apple platforms separate every screen into two layers:

1. Content layer — the app's actual content. Extends edge-to-edge, scrolls under everything, uses opaque backgrounds and standard materials.
2. Functional layer (Liquid Glass) — controls and navigation (tab bars, toolbars, sidebars, buttons) that float above content on a dynamic glass material. It has no color of its own; it refracts what's beneath, adapts light/dark from the underlying content, and keeps symbols monochrome by default.

Practical rules: bars are floating rounded/capsule islands, not full-width strips glued to edges. Content visibly scrolls beneath them. A scroll edge effect (progressive blur/fade) separates floating controls from content — never a hard hairline by default. Color on glass is reserved: tint the background of at most one prominent action (e.g. Done); everything else stays monochrome. Don't build content-layer cards out of glass — glass is for interactive chrome only.

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