iOS 26 Liquid Glass Design Pattern

Implement Apple's Liquid Glass design system introduced in iOS 26 (WWDC25) with graceful fallbacks for iOS 17-25. This skill covers adaptive glass styling, button styles, container effects, and the architectural patterns for building version-aware SwiftUI components.

Design Principles (WWDC25 Sessions 219, 323, 356)

Core Guidelines

1. Content-hugging shapes: Glass buttons should be capsule-shaped, NOT full-width
2. Hierarchy through prominence:
   • Primary actions → .glassProminent with tinting
   • Secondary actions → .glass without tinting
3. Never stack glass on glass: Avoid layering multiple glass effects
4. Capsule is default: Large/Extra-Large buttons automatically use capsule shapes

Visual Hierarchy