Apple HIG Designer

A professional-grade frontend design skill that enables Claude Code to create interfaces following Apple's Human Interface Guidelines (HIG), achieving the quality standards of Apple's design team.

When to Use This Skill

Activate this skill when users request:

• Apple-style or iOS/macOS-style interfaces
• HIG-compliant UI components
• SF Symbols integration
• San Francisco typography implementation
• Modern glass effects (optional, user must explicitly request)

Trigger phrases:

• "Design an Apple-style..."
• "Create a HIG-compliant..."
• "iOS/macOS style component"
• "苹果风格的界面"
• "符合 HIG 的设计"

---

Core Design Principles

The Four Pillars of Apple Design

1. Clarity (清晰)

   • Every element has a purpose
   • Eliminate unnecessary complexity
   • Users understand immediately without instructions
   • Use clear visual hierarchy

2. Deference (尊重内容)

   • UI elements support, not compete with content
   • Minimize chrome and visual noise
   • Let content be the hero
   • Use subtle backgrounds and borders

3. Depth (层次)

   • Create clear visual hierarchy through layers
   • Use shadows, blur, and translucency purposefully
   • Motion reinforces spatial relationships
   • Z-axis communicates importance

4. Consistency (一致性)

   • Familiar patterns across platforms
   • Predictable interactions
   • Unified visual language
   • Respect platform conventions

---

Design System Specifications

Typography System

Font Family: San Francisco (SF Pro)

/* System Font Stack for Web */
:root {
  --font-system: -apple-system, BlinkMacSystemFont, 'SF Pro Display',
                 'SF Pro Text', 'Helvetica Neue', Arial, sans-serif;
  --font-mono: 'SF Mono', SFMono-Regular, Menlo, Monaco, monospace;
}

/* Font Size Scale (iOS) */
--text-caption2: 11px;    /* Caption 2 */
--text-caption1: 12px;    /* Caption 1 */
--text-footnote: 13px;    /* Footnote */
--text-subhead: 15px;     /* Subheadline */
--text-body: 17px;        /* Body - Default */
--text-headline: 17px;    /* Headline (semibold) */
--text-title3: 20px;      /* Title 3 */
--text-title2: 22px;      /* Title 2 */
--text-title1: 28px;      /* Title 1 */
--text-large-title: 34px; /* Large Title */

Typography Rules:

• Use SF Pro Display for sizes ≥ 20pt
• Use SF Pro Text for sizes < 20pt
• Maintain consistent line-height (1.2-1.5)
• Use weight for hierarchy, not just size

Color System

/* Apple System Colors - Light Mode */
:root {
  /* Primary Colors */
  --system-blue: #007AFF;
  --system-green: #34C759;
  --system-indigo: #5856D6;
  --system-orange: #FF9500;
  --system-pink: #FF2D55;
  --system-purple: #AF52DE;
  --system-red: #FF3B30;
  --system-teal: #5AC8FA;
  --system-yellow: #FFCC00;

  /* Gray Scale */
  --system-gray: #8E8E93;
  --system-gray2: #AEAEB2;
  --system-gray3: #C7C7CC;
  --system-gray4: #D1D1D6;
  --system-gray5: #E5E5EA;
  --system-gray6: #F2F2F7;

  /* Semantic Colors */
  --label-primary: #000000;
  --label-secondary: rgba(60, 60, 67, 0.6);
  --label-tertiary: rgba(60, 60, 67, 0.3);
  --label-quaternary: rgba(60, 60, 67, 0.18);

  /* Backgrounds */
  --bg-primary: #FFFFFF;
  --bg-secondary: #F2F2F7;
  --bg-tertiary: #FFFFFF;

  /* Separators */
  --separator: rgba(60, 60, 67, 0.29);
  --separator-opaque: #C6C6C8;
}

/* Dark Mode */
@media (prefers-color-scheme: dark) {
  :root {
    --system-blue: #0A84FF;
    --system-green: #30D158;
    --system-indigo: #5E5CE6;
    --system-orange: #FF9F0A;
    --system-pink: #FF375F;
    --system-purple: #BF5AF2;
    --system-red: #FF453A;
    --system-teal: #64D2FF;
    --system-yellow: #FFD60A;

    --system-gray: #8E8E93;
    --system-gray2: #636366;
    --system-gray3: #48484A;
    --system-gray4: #3A3A3C;
    --system-gray5: #2C2C2E;
    --system-gray6: #1C1C1E;

    --label-primary: #FFFFFF;
    --label-secondary: rgba(235, 235, 245, 0.6);
    --label-tertiary: rgba(235, 235, 245, 0.3);
    --label-quaternary: rgba(235, 235, 245, 0.18);

    --bg-primary: #000000;
    --bg-secondary: #1C1C1E;
    --bg-tertiary: #2C2C2E;

    --separator: rgba(84, 84, 88, 0.6);
    --separator-opaque: #38383A;
  }
}

Spacing System

8pt Grid System:

:root {
  --space-1: 4px;   /* Extra small */
  --space-2: 8px;   /* Small */
  --space-3: 12px;  /* Medium-small */
  --space-4: 16px;  /* Medium */
  --space-5: 20px;  /* Medium-large */
  --space-6: 24px;  /* Large */
  --space-8: 32px;  /* Extra large */
  --space-10: 40px; /* 2X large */
  --space-12: 48px; /* 3X large */
}

Touch Target Requirements:

• iOS: Minimum 44×44 points
• visionOS: Minimum 60 points tap area
• Always add sufficient padding for small visual elements

Border Radius (Concentric Design)

:root {
  /* Base radius values */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 20px;
  --radius-2xl: 24px;
  --radius-full: 9999px; /* Capsule */
}

/* Concentric Rule: inner_radius + padding = outer_radius */
/* Example: 8px inner + 8px padding = 16px outer */

---

Component Patterns

Buttons

/* Primary Button - Capsule Style */
.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 12px 24px;
  font-family: var(--font-system);
  font-size: 17px;
  font-weight: 600;
  color: #FFFFFF;
  background: var(--system-blue);
  border: none;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: transform 0.1s ease, opacity 0.1s ease;
}

.btn-primary:hover {
  opacity: 0.9;
}

.btn-primary:active {
  transform: scale(0.98);
}

/* Secondary Button */
.btn-secondary {
  min-height: 44px;
  padding: 12px 24px;
  font-family: var(--font-system);
  font-size: 17px;
  font-weight: 600;
  color: var(--system-blue);
  background: rgba(0, 122, 255, 0.1);
  border: none;
  border-radius: var(--radius-full);
  cursor: pointer;
}

Glass Effect (Optional - Only When Requested)

Note: Glass/frosted effects should only be used when the user explicitly requests them. Default designs should use solid backgrounds for better readability and performance.

/* Glass Background - USE ONLY WHEN EXPLICITLY REQUESTED */
.glass-panel {
  background: rgba(255, 255, 255, 0.7);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border: 1px solid rgba(255, 255, 255, 0.3);
  border-radius: var(--radius-xl);
  box-shadow:
    0 4px 6px rgba(0, 0, 0, 0.02),
    0 12px 24px rgba(0, 0, 0, 0.04);
}

@media (prefers-color-scheme: dark) {
  .glass-panel {
    background: rgba(28, 28, 30, 0.7);
    border: 1px solid rgba(255, 255, 255, 0.1);
  }
}

Cards (Default - Solid Background)

.card {
  background: var(--bg-tertiary);
  border-radius: var(--radius-lg);
  padding: var(--space-4);
  box-shadow:
    0 1px 3px rgba(0, 0, 0, 0.04),
    0 4px 12px rgba(0, 0, 0, 0.04);
}

/* Card with Grouped Style */
.card-grouped {
  background: var(--bg-secondary);
  border-radius: var(--radius-xl);
  overflow: hidden;
}

.card-grouped-item {
  background: var(--bg-tertiary);
  padding: var(--space-4);
  border-bottom: 1px solid var(--separator);
}

.card-grouped-item:last-child {
  border-bottom: none;
}

Input Fields

.input-field {
  width: 100%;
  min-height: 44px;
  padding: 12px 16px;
  font-family: var(--font-system);
  font-size: 17px;
  color: var(--label-primary);
  background: var(--bg-secondary);
  border: none;
  border-radius: var(--radius-md);
  outline: none;
  transition: box-shadow 0.2s ease;
}

.input-field:focus {
  box-shadow: 0 0 0 4px rgba(0, 122, 255, 0.3);
}

.input-field::placeholder {
  color: var(--label-tertiary);
}

Tab Bars

Tab bars provide top-level navigation between app sections. Use filled SF Symbols and always show text labels.

Design Rules:

• Position at bottom of screen (iOS style)
• Minimum 44×44pt touch targets per tab
• Always display text labels (never icon-only)
• Use filled SF Symbols for selected state
• Support badge for notifications (red oval, white text)
• Never hide or disable tab buttons

/* Tab Bar Container */
.tab-bar {
  display: flex;
  justify-content: space-around;
  align-items: center;
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  height: 49px;
  padding-bottom: env(safe-area-inset-bottom);
  background: var(--bg-primary);
  border-top: 0.5px solid var(--separator);
}

/* Tab Item */
.tab-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-width: 44px;
  min-height: 44px;
  padding: 4px 12px;
  color: var(--system-gray);
  text-decoration: none;
  transition: color var(--duration-fast) var(--ease-default);
}

.tab-item--active {
  color: var(--system-blue);
}

.tab-item__icon {
  font-size: 24px;
  margin-bottom: 2px;
}

.tab-item__label {
  font-family: var(--font-system);
  font-size: 10px;
  font-weight: 500;
}

/* Badge */
.tab-item__badge {
  position: absolute;
  top: 2px;
  right: -6px;
  min-width: 18px;
  height: 18px;
  padding: 0 5px;
  font-size: 12px;
  font-weight: 600;
  color: #FFFFFF;
  background: var(--system-red);
  border-radius: 9px;
  text-align: center;
  line-height: 18px;
}

Toolbars

Toolbars provide context-specific actions. Organize items into three sections: leading, center, and trailing.

Design Rules:

• Three sections: leading (back/title), center (tools), trailing (actions)
• Maximum 3 item groups
• Use SF Symbols without borders
• Primary action uses .prominent style on trailing side
• Back button: circular with symbol only (no text)
• Titles: concise, under 15 characters

/* Toolbar Container */
.toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 44px;
  padding: 0 var(--space-4);
  background: var(--bg-primary);
  border-bottom: 0.5px solid var(--separator);
}

/* Toolbar Sections */
.toolbar__leading,
.toolbar__center,
.toolbar__trailing {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.toolbar__leading {
  min-width: 70px;
  justify-content: flex-start;
}

.toolbar__center {
  flex: 1;
  justify-content: center;
}

.toolbar__trailing {
  min-width: 70px;
  justify-content: flex-end;
}

/* Toolbar Title */
.toolbar__title {
  font-family: var(--font-system);
  font-size: 17px;
  font-weight: 600;
  color: var(--label-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* Toolbar Button */
.toolbar-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 44px;
  min-height: 44px;
  padding: var(--space-2);
  color: var(--system-blue);
  background: transparent;
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
}

.toolbar-btn:active {
  background: rgba(0, 122, 255, 0.1);
}

/* Back Button - Circular Symbol Only */
.toolbar-btn--back {
  width: 32px;
  height: 32px;
  min-width: 32px;
  padding: 0;
  border-radius: 50%;
}

/* Primary Action - Prominent Style */
.toolbar-btn--prominent {
  font-weight: 600;
  background: var(--system-blue);
  color: #FFFFFF;
  border-radius: var(--radius-full);
  padding: 8px 16px;
}

.toolbar-btn--prominent:active {
  opacity: 0.9;
}

Sheets

Sheets present scoped tasks in a modal overlay. Support multiple height detents and swipe-to-dismiss.

Design Rules:

• Detents: large (100%), medium (50%)
• Include grabber indicator for resizable sheets (36×5px)
• Done button: top-right corner
• Cancel button: top-left corner
• Semi-transparent backdrop (rgba(0,0,0,0.4))
• Only one sheet visible at a time

/* Sheet Backdrop */
.sheet-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.4);
  z-index: 100;
  opacity: 0;
  transition: opacity var(--duration-normal) var(--ease-default);
}

.sheet-backdrop--visible {
  opacity: 1;
}

/* Sheet Container */
.sheet {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  background: var(--bg-primary);
  border-radius: var(--radius-xl) var(--radius-xl) 0 0;
  z-index: 101;
  transform: translateY(100%);
  transition: transform var(--duration-normal) var(--ease-default);
  max-height: calc(100vh - 44px);
  overflow: hidden;
}

.sheet--visible {
  transform: translateY(0);
}

/* Sheet Detents */
.sheet--medium {
  height: 50vh;
}

.sheet--large {
  height: calc(100vh - 44px);
}

/* Grabber Indicator */
.sheet__grabber {
  width: 36px;
  height: 5px;
  background: rgba(60, 60, 67, 0.3);
  border-radius: 2.5px;
  margin: 8px auto;
}

@media (prefers-color-scheme: dark) {
  .sheet__grabber {
    background: rgba(235, 235, 245, 0.3);
  }
}

/* Sheet Header */
.sheet__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-3) var(--space-4);
  border-bottom: 0.5px solid var(--separator);
}

.sheet__cancel {
  color: var(--system-blue);
  font-size: 17px;
  background: none;
  border: none;
  cursor: pointer;
}

.sheet__done {
  color: var(--system-blue);
  font-size: 17px;
  font-weight: 600;
  background: none;
  border: none;
  cursor: pointer;
}

.sheet__title {
  font-family: var(--font-system);
  font-size: 17px;
  font-weight: 600;
  color: var(--label-primary);
}

/* Sheet Content */
.sheet__content {
  padding: var(--space-4);
  overflow-y: auto;
}

Alerts

Alerts deliver critical information requiring immediate attention. Use sparingly and provide clear actions.

Design Rules:

• Use only for critical information (sparingly)
• Maximum 3 buttons
• Button titles: specific verbs, avoid "OK"
• Cancel button: leading side (or bottom in stacked layout)
• Destructive style: only for unintended destructive actions
• Never show alerts at app startup

/* Alert Backdrop */
.alert-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.4);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 200;
}

/* Alert Container */
.alert {
  width: 270px;
  background: var(--bg-primary);
  border-radius: 14px;
  overflow: hidden;
  text-align: center;
}

@media (prefers-color-scheme: dark) {
  .alert {
    background: var(--bg-tertiary);
  }
}

/* Alert Content */
.alert__content {
  padding: 20px 16px;
}

.alert__title {
  font-family: var(--font-system);
  font-size: 17px;
  font-weight: 600;
  color: var(--label-primary);
  margin-bottom: 4px;
}

.alert__message {
  font-family: var(--font-system);
  font-size: 13px;
  color: var(--label-primary);
  line-height: 1.4;
}

/* Alert Buttons - Horizontal (2 buttons) */
.alert__buttons {
  display: flex;
  border-top: 0.5px solid var(--separator);
}

.alert__btn {
  flex: 1;
  padding: 12px;
  font-family: var(--font-system);
  font-size: 17px;
  color: var(--system-blue);
  background: transparent;
  border: none;
  cursor: pointer;
}

.alert__btn:not(:last-child) {
  border-right: 0.5px solid var(--separator);
}

.alert__btn:active {
  background: var(--bg-secondary);
}

/* Button Variants */
.alert__btn--cancel {
  font-weight: 400;
}

.alert__btn--default {
  font-weight: 600;
}

.alert__btn--destructive {
  color: var(--system-red);
}

/* Alert Buttons - Stacked (3+ buttons) */
.alert__buttons--stacked {
  flex-direction: column;
}

.alert__buttons--stacked .alert__btn {
  border-right: none;
  border-bottom: 0.5px solid var(--separator);
}

.alert__buttons--stacked .alert__btn:last-child {
  border-bottom: none;
}

Lists and Tables

Lists display rows of data with consistent structure. Distinguish between navigation (disclosure) and information (info button) accessories.

Design Rules:

• Minimum row height: 44px
• Info button (ⓘ): reveals details without navigation
• Disclosure indicator (>): navigates to subview
• Grouped style: 10px border-radius, 8px/16px margins
• Navigation: persistent highlight; Options: brief highlight + checkmark
• Inset separators start after leading content (60px)

/* List Container - Grouped Style */
.list {
  background: var(--bg-secondary);
}

.list-section {
  background: var(--bg-primary);
  border-radius: 10px;
  margin: var(--space-2) var(--space-4);
  overflow: hidden;
}

/* Section Header */
.list-section__header {
  padding: var(--space-2) var(--space-4);
  font-family: var(--font-system);
  font-size: 13px;
  font-weight: 400;
  color: var(--label-secondary);
  text-transform: uppercase;
  letter-spacing: 0.02em;
}

/* List Item */
.list-item {
  display: flex;
  align-items: center;
  min-height: 44px;
  padding: 12px var(--space-4);
  background: var(--bg-primary);
  position: relative;
}

/* Separator - Full Width */
.list-item:not(:last-child) {
  border-bottom: 0.5px solid var(--separator);
}

/* Separator - Inset (after leading image) */
.list-item--inset:not(:last-child) {
  border-bottom: none;
}

.list-item--inset:not(:last-child)::after {
  content: "";
  position: absolute;
  left: 60px;
  right: 0;
  bottom: 0;
  border-bottom: 0.5px solid var(--separator);
}

/* List Item Content */
.list-item__leading {
  width: 40px;
  height: 40px;
  margin-right: var(--space-3);
  border-radius: var(--radius-sm);
  overflow: hidden;
}

.list-item__content {
  flex: 1;
  min-width: 0;
}

.list-item__title {
  font-family: var(--font-system);
  font-size: 17px;
  color: var(--label-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.list-item__subtitle {
  font-family: var(--font-system);
  font-size: 15px;
  color: var(--label-secondary);
}

.list-item__value {
  font-family: var(--font-system);
  font-size: 17px;
  color: var(--label-secondary);
  margin-left: auto;
}

/* Accessories */
.list-item__accessory {
  margin-left: var(--space-2);
  color: var(--label-tertiary);
}

/* Disclosure Indicator - Navigation */
.list-item__disclosure {
  font-size: 14px;
  color: var(--label-quaternary);
}

/* Info Button - Details */
.list-item__info-btn {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  border: 1.5px solid var(--system-blue);
  color: var(--system-blue);
  font-size: 14px;
  font-weight: 600;
  display: flex;
  align-items: center;
  justify-content: center;
  background: transparent;
  cursor: pointer;
}

/* Checkmark - Selection */
.list-item__checkmark {
  color: var(--system-blue);
  font-size: 18px;
  font-weight: 600;
}

/* Selection States */
.list-item--selected {
  background: var(--system-blue);
}

.list-item--selected .list-item__title,
.list-item--selected .list-item__subtitle {
  color: #FFFFFF;
}

/* Interactive State */
.list-item:active {
  background: var(--bg-secondary);
}

---

Animation Guidelines

Timing Functions

:root {
  /* Apple's preferred easing */
  --ease-default: cubic-bezier(0.25, 0.1, 0.25, 1);
  --ease-in: cubic-bezier(0.42, 0, 1, 1);
  --ease-out: cubic-bezier(0, 0, 0.58, 1);
  --ease-in-out: cubic-bezier(0.42, 0, 0.58, 1);

  /* Spring-like easing */
  --ease-spring: cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

Duration Scale

:root {
  --duration-instant: 100ms;  /* Micro-interactions */
  --duration-fast: 200ms;     /* Hover, focus states */
  --duration-normal: 300ms;   /* Standard transitions */
  --duration-slow: 500ms;     /* Complex animations */
}

Interaction Feedback

/* Press feedback */
.interactive {
  transition: transform var(--duration-instant) var(--ease-out);
}

.interactive:active {
  transform: scale(0.97);
}

/* Hover glow */
.interactive:hover {
  box-shadow: 0 0 0 4px rgba(0, 122, 255, 0.15);
}

---

SF Symbols Integration

Rendering Modes

1. Monochrome: Single color for all layers
2. Hierarchical: Opacity variations for depth
3. Palette: Custom colors per layer
4. Multicolor: Apple's intrinsic symbol colors

Usage Guidelines

• Toolbar/Navigation: Use outline variant
• Tab Bar: Use fill variant
• Match text size: Symbols auto-align with SF font
• Provide text alternatives: Always include aria-label

Web Implementation (Icon Font Alternative)

<!-- Using SF Symbols via system font -->
<span class="sf-symbol" aria-label="Settings">􀣋</span>

<!-- Or use equivalent system icons -->
<svg class="icon" aria-hidden="true">
  <use href="#icon-gear"></use>
</svg>

---

Accessibility Requirements

Color Contrast

• Normal text: 4.5:1 minimum (WCAG AA)
• Large text: 3:1 minimum
• Interactive elements: Clearly distinguishable states

Motion

@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

Semantic HTML

<!-- Always use semantic elements -->
<button type="button">Action</button>
<nav aria-label="Main navigation">...</nav>
<main role="main">...</main>

---

Output Format

When generating Apple-style UI code, always include:

1. Complete, runnable code (CSS/React/Vue)
2. Light/Dark mode support via CSS custom properties
3. Design rationale explaining HIG compliance
4. Responsive breakpoints for different devices
5. Accessibility attributes (aria-*, role, etc.)

Default Behavior

• Use solid backgrounds by default for better readability
• Glass/blur effects only when user explicitly requests
• Always provide non-glass fallback for browsers without backdrop-filter support

Example Output Structure

/**
 * Apple HIG Compliant Component
 *
 * Design Decisions:
 * - Uses SF Pro system font stack for native feel
 * - 44pt minimum touch target for accessibility
 * - Capsule shape for primary actions (HIG recommendation)
 * - Solid background for optimal readability
 * - Supports prefers-color-scheme for auto theming
 */

const AppleButton = ({ children, variant = 'primary', ...props }) => {
  return (
    <button
      className={`btn btn-${variant}`}
      {...props}
    >
      {children}
    </button>
  );
};

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Best Practices Checklist

Before finalizing any design output, verify:

• Typography: Using SF Pro with correct size thresholds
• Colors: System colors with Light/Dark variants
• Spacing: Following 8pt grid
• Touch targets: Minimum 44×44pt
• Border radius: Concentric relationships maintained
• Animations: Using Apple-standard easing curves
• Accessibility: WCAG AA compliant, reduced motion support
• Consistency: Matches platform conventions
• Backgrounds: Solid by default, glass only when requested

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Resources

• Apple Human Interface Guidelines
• Apple Design Resources
• SF Symbols
• Apple Fonts

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This skill ensures Claude Code produces interfaces that meet Apple's exacting design standards, creating cohesive, accessible, and beautiful user experiences.