mobile-app-design-standards

name	Mobile App Design Standards
description	This skill should be used when the user asks to "design mobile UI", "review app design", "check UI guidelines", "improve app UX", "design React Native interface", "create app screens", "follow design standards", or mentions iOS/Android design patterns, accessibility, or mobile user experience. Provides comprehensive mobile app UI/UX design guidance.
version	0.1.0

Mobile App Design Standards

Comprehensive guidance for designing mobile applications that follow platform conventions, accessibility standards, and modern UX best practices.

Purpose

Apply platform-specific design guidelines, interaction patterns, and accessibility standards when designing, reviewing, or improving mobile application interfaces. Ensure designs are consistent, accessible, performant, and follow 2026 industry best practices.

When to Use This Skill

Use this skill when:

• Designing new mobile app screens or features
• Reviewing existing UI/UX implementations
• Planning interaction flows and navigation
• Establishing design systems or style guides
• Making platform-specific design decisions
• Optimizing for accessibility or performance
• Modernizing legacy mobile interfaces

Core Design Principles

Platform-Native Conventions

iOS (Human Interface Guidelines):

• Navigation: Back button in top-left, primary action in top-right
• Tab bar at bottom with 3-5 items
• Large titles for hierarchy
• System fonts: San Francisco (designed for small sizes)
• Haptic feedback for confirmations
• Swipe gestures for navigation

Android (Material Design):

• Navigation: Back in top-left, overflow menu in top-right
• Bottom navigation or navigation drawer
• Floating Action Button (FAB) for primary actions
• System fonts: Roboto
• Ripple effects for touch feedback
• Navigation drawer for hierarchical content

React Native Cross-Platform:

• Use platform-specific components where behavior differs
• Respect platform conventions for navigation patterns
• Test on both iOS and Android devices
• Consider using React Navigation for platform-aware navigation
• Use Platform API for conditional rendering

Touch Targets and Spacing

Minimum Sizes:

• iOS: 44 × 44 points minimum for all interactive elements
• Android: 48 × 48 dp minimum for all touch targets
• Spacing between targets: minimum 8dp/pt

Best Practices:

• Larger targets for primary actions (56dp FAB on Android)
• Adequate spacing prevents accidental taps
• Consider thumb zones on large screens
• Test with actual fingers, not mouse clicks

Typography Standards

Minimum Sizes:

• Body text: 16sp/pt minimum (14sp absolute minimum)
• Labels: 11-12pt minimum
• Avoid text smaller than 11pt for legibility

Hierarchy:

• Clear visual hierarchy through size, weight, color
• Consistent scale across the app (e.g., 12/14/16/20/24/32pt)
• Use platform system fonts unless brand requires custom
• Support dynamic type (iOS) and font scaling (Android)

Color and Contrast

WCAG Standards:

• Normal text: 4.5:1 contrast ratio minimum
• Large text (18pt+): 3:1 contrast ratio minimum
• UI components: 3:1 contrast ratio for boundaries

Color Usage:

• Don't rely solely on color to convey information
• Provide alternative indicators (icons, labels, patterns)
• Support dark mode where applicable
• Test color blindness scenarios

Component Architecture

Container/Presentational Pattern

Presentational Components:

• Focus on rendering UI elements
• Receive data via props
• No state management or business logic
• Highly reusable and testable

Container Components:

• Handle data fetching and state
• Manage business logic
• Pass data to presentational components
• Connect to app state/context

Atomic Design Methodology

Atoms: Basic building blocks (buttons, inputs, icons)

• Single-purpose components
• Highly reusable
• Consistent styling

Molecules: Simple component groups (form fields, search bars)

• Combine atoms into functional units
• Maintain single responsibility

Organisms: Complex component assemblies (headers, cards, forms)

• Combine molecules and atoms
• Represent distinct sections

Templates: Page-level layouts

• Define structure and placement
• No real content

Pages: Specific instances

• Real content applied to templates
• Actual screens in the app

Accessibility (a11y)

Screen Reader Support

Labels and Hints:

• All interactive elements need accessible labels
• Use accessibilityLabel (React Native) or contentDescription (Android)
• Provide hints for complex interactions
• Announce dynamic content changes

Navigation:

• Logical focus order (top to bottom, left to right)
• Skip navigation for repetitive content
• Clear heading hierarchy
• Announce screen changes

Cognitive Accessibility

Reduce Cognitive Load:

• Clear, concise labels (avoid jargon)
• Consistent patterns throughout app
• Progressive disclosure (show what's needed)
• Clear error messages with recovery steps

Focus Management:

• Highlight focused elements clearly
• Support keyboard navigation where applicable
• Maintain focus context during navigation

Performance Optimization

Perceived Performance

Loading States:

• Skeleton screens for content loading
• Progress indicators for operations >1 second
• Optimistic UI updates (show action immediately)
• Prevent layout shift during load

Responsiveness:

• Touch feedback within 100ms
• Visual feedback for all interactions
• Smooth animations (60fps target)
• Debounce rapid inputs

React Native Best Practices

Component Optimization:

• Use React.memo for expensive components
• Implement shouldComponentUpdate or useMemo
• Lazy load heavy components
• Virtualize long lists (FlatList, SectionList)

Bundle Optimization:

• Code splitting for large apps
• Remove unused dependencies
• Optimize image sizes and formats
• Use Hermes engine (Android)

Design System Essentials

Consistency Checklist

Visual Consistency:

• Unified color palette (primary, secondary, accent, neutrals)
• Typography scale defined (font sizes, weights, line heights)
• Spacing system (4pt/8pt grid or similar)
• Component library documented
• Icon set consistent in style and size

Behavioral Consistency:

• Navigation patterns unified
• Button actions predictable
• Form validation consistent
• Error handling standardized
• Loading states uniform

Component Documentation

Document each component with:

• Purpose and use cases
• Props and their types
• Visual variants (states, sizes, styles)
• Accessibility requirements
• Platform-specific considerations
• Usage examples

2026 Design Trends (Optional Enhancement)

AI-Driven Interaction

Predictive UI:

• Anticipate user needs based on context
• Smart defaults in forms
• Personalized content ordering
• Contextual suggestions

Conversational Interfaces:

• Voice interaction support
• Natural language input
• Progressive disclosure through conversation

Advanced Visual Design

Spatial Computing:

• Consider depth and layering
• Subtle parallax effects
• 3D elements where appropriate
• Immersive experiences

Micro-Interactions:

• Delightful animation details
• Haptic feedback coordination
• Sound design for actions
• Emotional engagement

Workflow Integration

Design Phase

1. Define requirements - Understand user needs and business goals
2. Research patterns - Review platform guidelines and competitors
3. Sketch wireframes - Low-fidelity layouts first
4. Create prototypes - Interactive mockups for testing
5. Validate designs - User testing and accessibility checks

Review Phase

When reviewing designs or implementations:

1. Check platform conventions (iOS vs Android)
2. Verify touch target sizes (44pt/48dp minimum)
3. Test color contrast ratios (WCAG AA minimum)
4. Validate accessibility labels
5. Confirm consistency with design system
6. Review performance considerations

Implementation Phase

1. Use presentational/container pattern
2. Build atomic components bottom-up
3. Implement accessibility from start
4. Test on real devices (both platforms)
5. Optimize for performance
6. Document component usage

Additional Resources

Reference Files

For detailed platform-specific guidance, consult:

Platform Guidelines:

• references/ios-guidelines.md - Comprehensive iOS HIG summary (SF Fonts, Navigation, VoiceOver, Haptics)
• references/android-guidelines.md - Material Design 3 essentials (Components, Motion, TalkBack)
• references/platform-differences.md - iOS vs Android quick reference (navigation, gestures, components)

Implementation Guides:

• references/accessibility-checklist.md - Complete WCAG 2.1 AA testing guide (screen readers, contrast, touch targets)
• references/performance-patterns.md - React Native optimization (FlatList, animations, bundle size, memory)
• references/common-mistakes.md - Common design errors and fixes (touch targets, typography, accessibility, forms)
• references/ui-libraries.md - React Native UI library comparison (Paper, Elements, Tamagui, NativeBase)

Example Files

Working code examples in examples/:

• profile-screen-example.tsx - Complete profile screen with Atomic Design, accessibility labels, performance optimization
• form-validation-example.tsx - Accessible form with real-time validation, proper keyboard types, error handling
• optimized-list-example.tsx - FlatList with virtualization, React.memo, skeleton loading, pull-to-refresh
• design-system-config.ts - Complete design tokens (colors, typography, spacing, shadows, component variants)

Utility Scripts

Development tools in scripts/:

• check-contrast.py - WCAG contrast ratio validator (usage: python check-contrast.py "#FFFFFF" "#000000")
• validate-touch-targets.sh - Validates minimum 44pt/48dp touch targets (usage: ./validate-touch-targets.sh src/)
• accessibility-audit.sh - Audits for missing labels, roles, and a11y issues (usage: ./accessibility-audit.sh src/)

Quick Reference

Touch Targets

• iOS: 44×44pt minimum
• Android: 48×48dp minimum

Typography

• Body: 16sp/pt minimum
• Labels: 11pt minimum

Contrast

• Text: 4.5:1 minimum
• Large text: 3:1 minimum
• Components: 3:1 minimum

Navigation

• iOS: Back top-left, action top-right, tabs bottom
• Android: Back top-left, menu top-right, FAB bottom-right

Performance

• Touch feedback: <100ms
• Animations: 60fps target
• Loading indicators: >1 second operations