UX Encyclopedia

Apple Human Interface Guidelines — Working Summary

Live source of truth: developer.apple.com/design/human-interface-guidelines (a living document — verify specifics there when precision matters). Covers iOS, iPadOS, macOS, watchOS, tvOS, visionOS.

Current state (mid-2026): Liquid Glass

At WWDC 2025 Apple shipped its biggest visual redesign since iOS 7: Liquid Glass, a dynamic translucent material that refracts and reflects surrounding content, applied across ALL platforms at once — with unified version numbering: iOS 26, iPadOS 26, macOS Tahoe 26, watchOS 26, tvOS 26, visionOS 26 (shipped fall 2025).

  • Where glass lives: Liquid Glass is reserved for the navigation/ control layer floating above content (tab bars, toolbars, sidebars, buttons, widgets, app icons) — NOT applied to content layers like lists, which look much as before. Hierarchy is expressed through depth, translucency, and refraction rather than opaque bars.
  • Fluid behavior: controls transform contextually — e.g., tab bars shrink on scroll-down to yield focus to content and re-expand on scroll-up; concentric corner radii align controls to hardware curves.
  • Apple's stated aims for the new system (WWDC25 sessions "Meet Liquid Glass" / "Get to know the new design system"): a unified, harmonized language across platforms; hierarchy through the glass layer; legibility of primary controls preserved via adaptive tinting/dimming.
  • Accessibility caution: the initial iOS 26 release drew documented legibility criticism (translucency over busy backgrounds reducing contrast — see NN/g coverage); Apple iterated through point releases, and at WWDC 2026 (June) announced iOS/iPadOS/macOS 27 with reduced default transparency and a user-facing opacity slider (shipping fall 2026 — in beta as of this writing). Design lesson: honor Reduce Transparency / Increase Contrast settings, and never place critical text directly on unmodified glass.

Historical framing (still useful context)

The HIG's long-standing trio for iOS (2013–2025 era): Clarity (legibility, precision, content-driven), Deference (UI serves content; fluid motion; content edge-to-edge), Depth (layers and realistic motion convey hierarchy). Liquid Glass is a continuation, not a reversal: deference and depth are now literalized in a refractive material layer. Overall approach remains: platform character + user control + direct manipulation + feedback + consistency + content-first design.

Key specifics to honor (stable across the redesign)

  • Touch targets: ≥44×44 pt.
  • Typography: San Francisco (SF Pro); Dynamic Type support expected — text styles (Large Title, Title 1–3, Body 17 pt, Caption…) that scale with user settings.
  • Navigation patterns: tab bar (2–5 top-level sections, persistent, now floating glass); navigation stack (title, back at top-left, edge-swipe back); modality used sparingly with obvious dismissal (sheets, full-screen covers).
  • SF Symbols: the system icon library — thousands of glyphs aligned to the type system with weights/scales; prefer these on Apple platforms.
  • Color: semantic system colors that adapt to light/dark and accessibility settings; avoid hard-coding. iOS 26 added system-generated icon appearance modes (light/dark/clear/tinted) from a single layered icon source (Icon Composer tool).
  • Layout: safe areas & layout margins; adaptivity across size classes (compact/regular) instead of per-device design.
  • Feedback & haptics: standard haptic patterns for success/warning/ selection; motion communicates hierarchy but respects Reduce Motion.
  • Permissions & onboarding: ask in context with purpose strings; brief-or-no tutorials; get people to content fast.
  • visionOS (spatial): windows/volumes/spaces; eyes+pinch as primary input; UI beyond arm's length; avoid head-locked content. Liquid Glass visibly borrows visionOS's glass material language.

Character in one line

Content-first minimalism with high polish: generous whitespace, type-led hierarchy, now a refractive glass control layer over edge-to-edge content, physicality in motion, and strict platform consistency.

Sources

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