Apple HIG SwiftUI iOS 26 / Swift 6.2 Best Practices

A principal designer's lens for evaluating and refactoring SwiftUI interfaces to Apple-quality standards, grounded in Rams, Segall, and Edson. Contains 51 rules across 8 categories, each grounded in specific principles from three foundational design texts:

• Dieter Rams — Ten Principles for Good Design ("less, but better," "design should be honest")

• Ken Segall — Insanely Simple (simplicity as a core principle for intuitive, beautiful products)

• John Edson — Design Like Apple (design-focused culture, prototyping to perfection, the product is the marketing)

Categories are ordered by a visual review process: start with what to remove, then what to clarify, then what to make honest, invisible, systematic, thorough, enduring, and finally what to refine.

Scope & Relationship to Sibling Skills

This skill is the refactoring and review lens — it evaluates existing UI and identifies visual anti-patterns to fix. When loaded alongside ios-design (building new UI), ios-hig (HIG compliance), or swift-refactor (code-level refactoring), this skill supersedes overlapping rules with more detailed "incorrect -> correct" transformations and "When NOT to apply" guidance. Use this skill for auditing and improving existing screens; use the siblings for greenfield implementation.

Clinic Architecture Contract (iOS 26 / Swift 6.2)

All guidance in this skill assumes the clinic modular MVVM-C architecture:

• Feature modules import Domain

• DesignSystem only (never Data , never sibling features)

• App target is the convergence point and owns DependencyContainer , concrete coordinators, and Route Shell wiring

• Domain stays pure Swift and defines models plus repository, *Coordinating , ErrorRouting , and AppError contracts

• Data owns SwiftData/network/sync/retry/background I/O and implements Domain protocols

• Read/write flow defaults to stale-while-revalidate reads and optimistic queued writes

• ViewModels call repository protocols directly (no default use-case/interactor layer)

When to Apply

Reference these guidelines when:

• Reviewing existing SwiftUI screens for visual quality issues

• Auditing whether every element on screen earns its place (Rams #10)

• Evaluating if the interface is self-explanatory without tooltips (Rams #4)

• Checking that colors, states, and hierarchy tell the truth (Rams #6)

• Ensuring animations and materials are invisible, not decorative (Rams #5)

• Verifying spacing, radii, and colors form a coherent system (Edson "Systems Thinking")

• Confirming edge cases — reduce motion, touch targets, safe areas — are handled (Rams #8)

• Adopting iOS 26 / Swift 6.2 APIs that refine previously impossible interactions (Edson "Design Out Loud")

Rule Categories by Priority

Priority Category Principle Impact Prefix Rules

1 Less, But Better Rams #10 + Segall "Think Minimal" CRITICAL less-

7

2 Self-Evident Design Rams #4 + Segall "Think Human" CRITICAL evident-

6

3 Honest Interfaces Rams #6 + Segall "Think Brutal" CRITICAL honest-

6

4 Invisible Design Rams #5 + Edson "Product Is Marketing" HIGH invisible-

6

5 Systems, Not Pieces Edson "Systems Thinking" + Rams #8 HIGH system-

6

6 Thorough to the Last Detail Rams #8 + Rams #2 HIGH thorough-

7

7 Enduring Over Trendy Rams #7 + Edson "Design With Conviction" MEDIUM-HIGH enduring-

5

8 Refined Through Iteration Edson "Design Out Loud" + Rams #1/#3 MEDIUM refined-

8

Quick Reference

1. Less, But Better (CRITICAL)

Rams #10: "Good design is as little design as possible." Segall: Apple succeeded by saying no to a thousand things.

• less-single-focal

• One primary focal point per screen

• less-type-restraint

• Limit to 3-4 distinct type treatments per screen

• less-one-typeface

• One typeface per app, differentiate with weight and size

• less-color-restraint

• Reserve saturated colors for small interactive elements

• less-one-color-purpose

• Each semantic color serves exactly one purpose

• less-purposeful-motion

• Every animation must communicate state change or provide feedback

• less-fewer-controls

• Remove controls that do not serve the core task

2. Self-Evident Design (CRITICAL)

Rams #4: "Good design makes a product understandable." Segall: interfaces must speak in terms people understand.

• evident-visual-weight

• Combine size, weight, and contrast for hierarchy

• evident-whitespace-grouping

• Use whitespace to separate conceptual groups

• evident-progressive-disclosure

• Use progressive disclosure for dense information

• evident-reading-order

• Align visual weight with logical reading order

• evident-navigation-intent

• Sheets for tasks and creation, push for drill-down hierarchy

• evident-label-clarity

• Use clear labels over ambiguous icons

3. Honest Interfaces (CRITICAL)

Rams #6: "Good design is honest." Segall: clarity without sugar-coating.

• honest-semantic-colors

• Use semantic colors, never hard-coded black or white

• honest-contrast

• Ensure WCAG AA contrast ratios

• honest-dark-mode

• Define light and dark variants for every custom color

• honest-foreground-style

• Use foregroundStyle over foregroundColor

• honest-depth-cues

• Use materials for layering, not drop shadows for depth

• honest-loading-states

• Show real progress, not indefinite spinners

4. Invisible Design (HIGH)

Rams #5: "Good design is unobtrusive." Edson: the product itself is the marketing.

• invisible-spring-physics

• Default to spring animations for all UI transitions

• invisible-spring-presets

• Use .smooth for routine, .snappy for interactive, .bouncy for delight

• invisible-no-easing

• Prefer springs over linear and easeInOut for UI elements

• invisible-system-materials

• Use system materials, not custom semi-transparent backgrounds

• invisible-symbol-effects

• Use built-in symbolEffect, not manual symbol animation

• invisible-content-transitions

• Use contentTransition for changing text and numbers

5. Systems, Not Pieces (HIGH)

Edson: "Design is systems thinking." Rams #8: nothing must be arbitrary or left to chance.

• system-spacing-grid

• Use a 4pt base unit for all spacing

• system-consistent-padding

• Use consistent padding across all screens

• system-corner-radii

• Standardize corner radii per component type

• system-alignment

• Consistent alignment per content type within a screen

• system-color-naming

• Name custom colors by role, not hue

• system-brand-integration

• Map brand palette onto iOS semantic color roles

6. Thorough to the Last Detail (HIGH)

Rams #8: "Care and accuracy in the design process show respect for the user." Rams #2: if the user cannot reliably use it, the product has failed.

• thorough-reduce-motion

• Always provide reduce motion fallback

• thorough-touch-targets

• All interactive elements at least 44x44 points

• thorough-safe-areas

• Always respect safe areas

• thorough-readable-weights

• Avoid light font weights for body text

• thorough-vibrancy-levels

• Match vibrancy level to content importance

• thorough-material-thickness

• Choose material thickness by contrast needs

• thorough-background-interaction

• Enable background interaction for peek-style sheets

7. Enduring Over Trendy (MEDIUM-HIGH)

Rams #7: "Good design is long-lasting." Edson: commit to a voice that persists across product generations.

• enduring-system-text-styles

• Use Apple text styles, never fixed font sizes

• enduring-weight-not-caps

• Use weight for emphasis, not ALL CAPS

• enduring-swipe-back

• Never break the system back-swipe gesture

• enduring-zoom-navigation

• Use zoom transitions for collection-to-detail navigation

• enduring-card-modularity

• Use self-contained cards for dashboard layouts

8. Refined Through Iteration (MEDIUM)

Edson: "Design out loud" — prototype relentlessly until every interaction feels inevitable. Rams #1: innovation serves genuine purpose.

• refined-scroll-transitions

• Use scrollTransition for scroll-position visual effects

• refined-phase-animator

• Use PhaseAnimator for multi-step animation sequences

• refined-mesh-gradients

• Use MeshGradient for premium dynamic backgrounds

• refined-text-renderer

• Use TextRenderer for hero text animations only

• refined-inspector

• Use inspector for trailing-edge detail panels

• refined-multi-detent

• Provide multiple sheet detents with drag indicator

• refined-matched-geometry

• Use matchedGeometryEffect for contextual origin transitions

• refined-no-hard-cuts

• Always animate between states, even minimally

How to Use

Read individual reference files for detailed explanations and code examples:

• Section definitions - Category structure, principle sources, and impact levels

• Rule template - Template for adding new rules

Reference Files

File Description

references/_sections.md Category definitions and principle grounding

assets/templates/_template.md Template for new rules

metadata.json Version and reference information