Frontend design

Frontend Design

Create distinctive, production-grade frontend interfaces with intentional aesthetics.

Purpose

This skill guides creation of frontend interfaces that feel genuinely designed—not auto-generated. It covers design thinking, interaction patterns, motion, forms, layout, accessibility, and performance.

When to Activate

Use this skill when:

• Building UI components or pages
• Making design decisions for frontend work
• Reviewing UI implementation quality
• Planning interaction patterns

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1. Design Thinking

Before writing any code, establish your design intent:

Purpose & Context

What problem are we solving? Who uses this? Think about the user's emotional state, their goals, and what success looks like.

Aesthetic Direction

Choose a clear visual direction:

Direction	Feel	When to Use
Warm Minimal	Clean, inviting, focused	Dashboard UIs, tools, productivity
Editorial	Magazine-like, typographic	Content-heavy pages, portfolios
Soft/Organic	Rounded, gentle, approachable	Consumer apps, onboarding
Industrial/Raw	Utilitarian, honest, functional	Developer tools, technical docs
Luxury/Refined	Spacious, elegant, deliberate	Brand sites, premium products

Key insight: Bold maximalism and refined minimalism both work—the magic is in commitment, not intensity.

The Memorable Detail

Ask yourself: What's the one thing someone will remember about this interface? Maybe it's a delightful hover state, an unexpected color choice, or how perfectly the typography flows.

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2. Design System Integration

Color Philosophy

/* Use semantic tokens, not arbitrary colors */
--bg-primary      /* Main background */
--bg-secondary    /* Elevated surfaces */
--fg-primary      /* Primary text */
--fg-secondary    /* Secondary text */
--border-primary  /* Interactive borders */
--border-secondary /* Container borders */
--brand-primary   /* Accent/CTA color */

Typography Hierarchy

Category	Usage
Display	Headlines, titles, hero text
Body	Paragraphs, inputs, tabs
Small	Labels, captions, hints, metadata
Accent	Special callouts, tech feel (use sparingly)

Border Philosophy

Borders should support, not dominate:

// Default: nearly invisible
className="border border-border-secondary"

// Hover: slightly more visible
className="hover:border-border-primary"

// Focus: full visibility
className="focus:border-border-primary"

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3. Interaction Patterns

Hit Targets & Touch

Context	Minimum Size	Notes
Desktop	24×24px	Visual can be smaller if hit area is expanded
Mobile	44×44px	Apple HIG standard
Input font	≥16px	Prevents iOS Safari auto-zoom

// Expand hit target beyond visual bounds
<button className="p-2 -m-2">
  <Icon className="w-6 h-6" /> {/* Visual is 24px, hit area is 40px */}
</button>

Focus Management

• Use :focus-visible over :focus to avoid focus rings on click
• Use :focus-within for grouped controls (e.g., input with icon)
• Every focusable element requires a visible focus state
• Implement focus traps in modals/drawers per WAI-ARIA patterns

Loading States

Timing	Value	Purpose
Show delay	150–300ms	Prevent flash on fast responses
Minimum visible	300–500ms	Avoid jarring disappearance

// Don't: Show spinner immediately
{isLoading && <Spinner />}

// Do: Delay spinner appearance
const showSpinner = isLoading && loadingDuration > 200;

Optimistic Updates

Update the UI immediately when success is likely:

1. Show change instantly
2. Send request to server
3. On success: confirm (subtle)
4. On failure: rollback + show error + offer retry

Destructive Actions

Pattern	When to Use
Confirmation dialog	Permanent deletion, irreversible changes
Undo with timeout	Soft deletes, sends, publishes
Type-to-confirm	Account deletion, production deployments

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4. Motion & Animation

When to Animate

Animate only when it serves a purpose:

• Clarify cause/effect: Show where something came from or went
• Maintain context: Help users track changes during transitions
• Deliberate delight: Reward interactions meaningfully

Don't animate for decoration or to fill silence.

Easing Selection

Property Changing	Recommended Easing
Opacity only	linear or gentle ease
Size/Scale	easeOut (fast start, slow end)
Position	easeOut or spring
Enter	easeOut
Exit	easeIn (slow start, fast end)

Performance Rules

GPU-accelerated (prefer these):

transform: translate(), scale(), rotate();
opacity;
filter;

Layout-triggering (avoid animating):

width, height, padding, margin;
top, left, right, bottom;
font-size, line-height;

Anti-patterns:

/* Never: Animates everything including layout */
transition: all 0.3s;

/* Do: Explicit properties only */
transition: transform 0.3s, opacity 0.3s;

Accessibility (prefers-reduced-motion)

Always honor the user's motion preference:

const prefersReducedMotion = window.matchMedia(
  '(prefers-reduced-motion: reduce)'
).matches;

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5. Form Design

Submission Behavior

Input Type	Enter Key Behavior
Single text input	Submits form
Multiple inputs	Submits on last field
<textarea>	Creates new line
<textarea> + Cmd/Ctrl+Enter	Submits form

Validation Patterns

Timing	What to Validate
On blur	Format, required fields
On submit	All validation, server errors
Real-time	Only for character limits or live search

Rules:

• Show errors adjacent to the field, not in a summary
• On submit error, focus the first invalid field
• Don't pre-disable submit—let users discover issues

Mobile Considerations

• Input font ≥16px prevents iOS auto-zoom
• Use correct type and inputmode for better keyboards:

Data	type	inputmode
Email	email	—
Phone	tel	—
Number	text	numeric
Credit card	text	numeric

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6. Layout Principles

Optical Alignment

Geometry lies. Adjust ±1–2px when perception beats math:

• Circles and triangles appear smaller than squares at same dimensions
• Text with descenders needs more bottom padding
• Icons may need nudging to appear centered

Nested Border Radius

Child radius must be ≤ parent radius, and curves should be concentric:

Outer radius: 16px
Gap (padding): 8px
Inner radius: 16px - 8px = 8px

Layered Shadows

Use ≥2 shadow layers to mimic real light (ambient + direct):

box-shadow:
  0 1px 2px rgba(0,0,0,0.06),    /* Tight, direct light */
  0 4px 12px rgba(0,0,0,0.08);   /* Soft, ambient light */

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7. Accessibility

Contrast Standards

• Prefer APCA over WCAG 2 for more accurate perceptual contrast
• Interactive states must have more contrast than rest state

Color Independence

Never rely on color alone for meaning:

• Error states: color + icon + text
• Status indicators: color + label
• Charts: color + pattern or label

Screen Reader Support

• Icon-only buttons require aria-label
• Decorative elements get aria-hidden="true"
• Use native elements (button, a, label) before ARIA
• Maintain logical heading hierarchy (h1 → h2 → h3)

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8. Performance

Response Time Targets

Operation	Target
UI response to input	<100ms
API mutations	<500ms
Page load (LCP)	<2.5s

Rendering Optimization

• Virtualize lists >100 items
• Use content-visibility: auto for off-screen content
• Minimize React re-renders

Asset Loading

Asset	Strategy
Above-fold images	Preload
Below-fold images	Lazy load
Fonts	Preload critical, subset via unicode-range
Third-party scripts	defer or async

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9. What to Avoid

Generic AI aesthetics:

• Overused fonts (Inter, Roboto, Arial as primary)
• Purple gradients on white backgrounds
• Predictable layouts without character
• Cookie-cutter component patterns

Interaction anti-patterns:

• transition: all (performance killer)
• Autoplay animations
• Disabled submit buttons before user tries
• Blocking paste on any input
• Color-only status indicators

Instead:

• Make unexpected choices that feel genuinely designed
• Match implementation complexity to aesthetic vision
• Commit fully to your visual direction

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Related Skills

• design-system-quality
• brand-guidelines
• brand-voice

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Version: 1.0.0 | Interaction patterns adapted from Vercel Web Interface Guidelines