name: ios-ui-ux-design
description: Design iOS app interfaces following Apple Human Interface Guidelines (HIG). Use when creating UI designs, defining design systems, planning user flows, selecting colors/typography, designing for accessibility, or ensuring iOS platform consistency. Fourth step in the idea-to-App-Store workflow.

iOS UI/UX Design

Design beautiful, intuitive iOS apps following Apple's Human Interface Guidelines.

Design Principles

Apple's Core Principles

1. Aesthetic Integrity - Appearance matches function
2. Consistency - Familiar patterns and behaviors
3. Direct Manipulation - Engage with content, not controls
4. Feedback - Acknowledge every action
5. Metaphors - Build on familiar experiences
6. User Control - Users initiate and control actions

Design System

Color Palette

// System Colors (adapt to light/dark mode)
Color.primary      // Label text
Color.secondary    // Secondary text
Color.accentColor  // Tint, buttons
Color(.systemBackground)
Color(.secondarySystemBackground)
Color(.tertiarySystemBackground)

// Semantic Colors
Color.red          // Destructive actions
Color.green        // Success, positive
Color.blue         // Links, primary actions
Color.orange       // Warnings
Color.yellow       // Highlights

Typography Scale

// SwiftUI Usage
Text("Title").font(.largeTitle)
Text("Body").font(.body)
Text("Caption").font(.caption)

Spacing System

4pt  - Minimal spacing
8pt  - Tight spacing (related elements)
12pt - Default compact
16pt - Standard spacing
20pt - Comfortable spacing  
24pt - Section spacing
32pt - Large gaps

Corner Radius

Screen Patterns

Navigation Patterns

Tab Bar (3-5 items)
├── Best for: Primary destinations
├── Always visible at bottom
└── Icons + Labels recommended

Navigation Stack
├── Best for: Hierarchical content
├── Back button auto-added
└── Large titles collapse on scroll

Sidebar (iPad)
├── Best for: Document apps
├── Collapsible on compact width
└── Primary/Detail split view

Common Screens

Onboarding

Page 1: Value proposition (benefit-focused)
Page 2: Key feature highlight
Page 3: Key feature highlight  
Page 4: Permissions/Sign up CTA

Design Tips:
- 3-5 pages maximum
- Skip button visible
- Progress indicator
- Illustrations > screenshots

Lists

// Standard List Row
HStack {
    Image(systemName: "icon")
        .frame(width: 30)
    VStack(alignment: .leading) {
        Text("Title").font(.body)
        Text("Subtitle").font(.caption).foregroundColor(.secondary)
    }
    Spacer()
    Image(systemName: "chevron.right")
        .foregroundColor(.secondary)
}
.padding(.vertical, 8)

Forms

- Group related fields
- Use Section headers
- Show validation inline
- Keyboard type per field
- Next/Done toolbar buttons

Empty States

Components:
- Illustration (SF Symbol or custom)
- Title (what's missing)
- Description (how to fix)
- Action button (primary CTA)

Tone: Helpful, not critical

iOS-Specific Patterns

Safe Areas

// Respect safe areas for:
- Top (notch, Dynamic Island)
- Bottom (home indicator)
- Keyboard avoiding

// Extend to edges for:
- Full-screen images
- Tab bar backgrounds
- Navigation bar backgrounds

Touch Targets

Minimum: 44x44 points
Recommended: 48x48 points
Spacing between: 8pt minimum

Gestures

Haptics

// Use sparingly for:
- Button taps
- Toggle changes
- Success/error feedback
- Picker selection

// Types:
UIImpactFeedbackGenerator(.light)    // Subtle
UIImpactFeedbackGenerator(.medium)   // Standard  
UIImpactFeedbackGenerator(.heavy)    // Emphasized
UINotificationFeedbackGenerator()    // Success/warning/error
UISelectionFeedbackGenerator()       // Selection changes

Accessibility

Requirements Checklist

• [ ] VoiceOver labels for all interactive elements
• [ ] Dynamic Type support (all text scales)
• [ ] Sufficient color contrast (4.5:1 for text)
• [ ] No color-only information
• [ ] Reduce Motion alternative animations
• [ ] Bold Text support
• [ ] Button Shapes support

Accessibility Implementation

// VoiceOver
Text("Send")
    .accessibilityLabel("Send message")
    .accessibilityHint("Double tap to send your message")

// Dynamic Type
Text("Scales")
    .font(.body)  // Automatically scales

// Fixed size (use sparingly)
Text("Fixed")
    .dynamicTypeSize(.large)

Dark Mode

Design Considerations

Light Mode          Dark Mode
-----------         ----------
White bg     →      System black
Black text   →      White text
Gray 100     →      Gray 900
Vibrant colors →    Desaturated colors
Drop shadows →      Inner shadows/borders

Testing Checklist

• [ ] All text readable in both modes
• [ ] Images work in both modes (use template images)
• [ ] No pure white on dark mode (use system colors)
• [ ] Sufficient contrast maintained
• [ ] Custom colors adapt properly

Design Handoff

Asset Export

Figma/Sketch Handoff

Include:
- Component specifications
- Spacing annotations  
- Color tokens
- Typography specs
- Interaction notes
- Asset exports

Design Review Checklist

Before Development

• [ ] All screens designed for light + dark mode
• [ ] iPhone + iPad layouts (if Universal)
• [ ] Empty states designed
• [ ] Error states designed
• [ ] Loading states designed
• [ ] Accessibility reviewed
• [ ] Haptic feedback specified
• [ ] Transitions/animations documented

Platform Consistency

• [ ] Uses SF Symbols where possible
• [ ] Follows iOS navigation patterns
• [ ] Respects safe areas
• [ ] 44pt minimum touch targets
• [ ] System fonts for body text
• [ ] Native controls where appropriate

Resources

• Apple HIG
• SF Symbols
• Apple Design Resources

See references/hig-checklist.md for detailed HIG compliance checklist.