Frontend UI Design

Create visually distinctive, aesthetically pleasing frontend interfaces that avoid generic "AI slop" patterns.

When to Use

Use this skill when:

• User requests frontend UI creation (HTML, CSS, JavaScript, or React)
• User asks to build a webpage, landing page, or web interface
• User wants to create visual components or layouts
• User mentions design, aesthetics, or "make it look good"
• User asks for dashboard, portfolio, or application UI

Core Principle

CRITICAL: Without explicit aesthetic guidance, Claude defaults to generic, conservative designs (white backgrounds, purple accents, Inter/Roboto fonts, predictable layouts). This skill provides research-backed strategies to create distinctive, visually interesting interfaces.

The Four Design Dimensions

Always address these four areas when creating frontend UIs:

1. Typography

AVOID these overused fonts:

• Inter, Roboto, Arial, Helvetica, system fonts

USE distinctive alternatives:

• Monospace: JetBrains Mono, Fira Code, IBM Plex Mono, Space Mono
• Display/Geometric: Space Grotesk, Clash Display, Epilogue, Syne
• Serif: Playfair Display, Crimson Pro, Libre Baskerville, Merriweather
• Modern Sans: Outfit, Manrope, General Sans, Satoshi

Typography Best Practices:

• Use high contrast pairings: display + monospace, serif + geometric sans
• Employ extreme weight variations: 100/200 vs 800/900 (not just 400 vs 600)
• Create dramatic size jumps: 3x+ differences, not 1.5x
• Load fonts from Google Fonts and state choices explicitly before coding

Example pairing:

Heading: Clash Display (800 weight, 4rem)
Body: JetBrains Mono (300 weight, 0.9rem)
Accent: Space Grotesk (700 weight, 1.2rem)

2. Color & Theme

AVOID these clichéd schemes:

• Purple gradients on white backgrounds
• Generic blue-and-white corporate palettes
• Timid, evenly-distributed colors
• Predictable light mode with subtle accents

USE cohesive aesthetics with CSS variables:

• Commit to a theme: Cyberpunk, Solarpunk, Brutalist, Neo-Tokyo, Retro-Future, Terminal, Vaporwave
• Dominant colors with sharp accents: Not all colors equally represented
• Draw from IDE themes: Dracula, Nord, Gruvbox, Tokyo Night, Monokai
• Cultural aesthetics: Japanese minimalism, Swiss design, Memphis style

Color Strategy:

1. Define CSS custom properties for consistency
2. Choose 2-3 dominant colors and 1-2 sharp accents
3. Consider dark themes as often as light themes
4. Use gradients sparingly but boldly when used

Example theme (Cyberpunk):

--bg-primary: #0a0e27;
--bg-secondary: #16213e;
--accent-neon: #00ff9f;
--accent-pink: #ff006e;
--text-primary: #e0e0e0;
--text-muted: #8892b0;

3. Motion

Implementation approach:

• For HTML: CSS-only animations
• For React: Use Framer Motion library when available
• Focus on high-impact moments over scattered micro-interactions
• One well-orchestrated page load with staggered reveals > many small animations

Motion Best Practices:

• Use animation-delay for staggered effects
• Animate on mount/page load for impact
• Keep animations smooth (ease-out, ease-in-out)
• Duration: 0.4s-0.8s for most transitions

Example staggered reveal:

.fade-in {
  animation: fadeIn 0.6s ease-out forwards;
  opacity: 0;
}

.fade-in:nth-child(1) { animation-delay: 0.1s; }
.fade-in:nth-child(2) { animation-delay: 0.2s; }
.fade-in:nth-child(3) { animation-delay: 0.3s; }

@keyframes fadeIn {
  to { opacity: 1; transform: translateY(0); }
  from { opacity: 0; transform: translateY(20px); }
}

4. Backgrounds

AVOID: Solid white or solid single-color backgrounds

USE atmosphere and depth:

• Layered CSS gradients: Multiple gradients with varying opacity
• Geometric patterns: Grid lines, dots, diagonal stripes
• Contextual effects: Noise texture, grain, subtle animations
• Thematic elements: Match overall aesthetic (circuits for tech, organic shapes for nature)

Background Techniques:

/* Layered gradients */
background:
  radial-gradient(circle at 20% 50%, rgba(120, 0, 255, 0.3) 0%, transparent 50%),
  radial-gradient(circle at 80% 80%, rgba(0, 255, 200, 0.2) 0%, transparent 50%),
  linear-gradient(135deg, #0a0e27 0%, #16213e 100%);

/* Grid pattern */
background-image:
  linear-gradient(rgba(255, 255, 255, 0.05) 1px, transparent 1px),
  linear-gradient(90deg, rgba(255, 255, 255, 0.05) 1px, transparent 1px);
background-size: 50px 50px;

/* Dots pattern */
background-image: radial-gradient(circle, rgba(255, 255, 255, 0.1) 1px, transparent 1px);
background-size: 20px 20px;

Critical Warnings: Avoid "AI Slop"

Think outside the box! It is CRITICAL that you:

• ✅ Vary between light and dark themes (don't default to light)
• ✅ Use different fonts each time (avoid convergence on Space Grotesk)
• ✅ Try different aesthetics (cyberpunk, brutalist, retro, minimalist)
• ❌ Never use: Inter, Roboto, Arial as primary fonts
• ❌ Never default to: White background with purple accents
• ❌ Avoid: Cookie-cutter layouts, predictable component patterns
• ❌ Don't create: Generic designs lacking context-specific character

Workflow

When creating frontend UIs, follow this process:

Step 1: Understand Context

Ask clarifying questions about:

• Purpose of the interface
• Target audience
• Desired mood/feeling
• Any specific aesthetic preferences

Step 2: Choose Aesthetic Direction

Pick a cohesive theme based on context:

• Tech/Dev: Terminal, Cyberpunk, Hacker aesthetic
• Creative: Vaporwave, Memphis, Brutalist
• Professional: Swiss design, Minimalist, Editorial
• Organic: Solarpunk, Nature-inspired, Warm tones

Step 3: State Design Decisions Explicitly

Before writing code, declare:

Theme: [chosen aesthetic]
Fonts: [heading font], [body font], [accent font]
Colors: [dominant colors and accents]
Motion: [key animations planned]
Background: [approach chosen]

Step 4: Implement with Best Practices

Technical Requirements:

• Use vanilla HTML, CSS, JavaScript OR React as requested
• Include Tailwind CSS if appropriate
• Inline all CSS and JavaScript for single-file deliverables
• Load fonts from Google Fonts
• Use CSS custom properties for theming
• Ensure responsive design (mobile-first approach)

Step 5: Create High-Impact Moments

• Orchestrate page load animations
• Use staggered reveals for content
• Add hover states that feel responsive
• Consider scroll-triggered animations sparingly

Examples

Example 1: Developer Portfolio (Dark Theme)

Stated Design:

• Theme: Terminal/Hacker aesthetic with green accents
• Fonts: JetBrains Mono (all text), weight variations for hierarchy
• Colors: Dark bg (#0d1117), green accent (#39ff14), muted gray text
• Motion: Typing animation on hero text, staggered fade-in on projects
• Background: Subtle grid pattern with scanline effect

Key Features:

• Monospace typography throughout
• CRT monitor aesthetic with scanlines
• Green phosphor glow effects
• Terminal-style navigation

Example 2: Creative Agency Landing (Light Theme)

Stated Design:

• Theme: Swiss Brutalist with bold typography
• Fonts: Clash Display (headings 900 weight), Space Grotesk (body 300 weight)
• Colors: Off-white (#f5f5f0), black, one sharp red accent (#ff0000)
• Motion: Bold elements sliding in from edges on load
• Background: Off-white with subtle noise texture

Key Features:

• Extreme type sizing (hero at 6rem+)
• Asymmetric grid layout
• Sharp geometric shapes as accents
• High contrast black/white with red sparingly

Example 3: App Dashboard (Dark Theme)

Stated Design:

• Theme: Neo-Tokyo night with pink/cyan accents
• Fonts: Outfit (headings 700), IBM Plex Mono (data/numbers)
• Colors: Dark navy (#0a1128), pink (#ff006e), cyan (#00f5ff)
• Motion: Smooth transitions on card hovers, data count-up animations
• Background: Dark with subtle radial gradient and grid

Key Features:

• Neon-style accents on interactive elements
• Glassmorphism cards with backdrop blur
• Monospace for all numerical data
• Glowing borders on focus states

Isolated Dimension Prompting

For targeted control, you can isolate single dimensions:

Typography-Only Adjustment

"Keeping all other design elements the same, update only the typography using Crimson Pro for headings and Fira Code for body text with extreme weight contrast."

Theme-Only Adjustment

"Lock the aesthetic to a Solarpunk theme: warm earth tones, organic shapes, nature-inspired patterns, green/gold accents, optimistic futuristic feel."

Motion-Only Enhancement

"Add a well-orchestrated page load sequence: hero fades in first (0.5s), then navigation staggers in (0.2s delays), then content cards reveal bottom-to-top."

Font Rotation Strategy

To avoid convergence on the same fonts, rotate through these distinctive combinations:

Set 1 - Terminal Aesthetic:

• JetBrains Mono + IBM Plex Mono

Set 2 - Modern Editorial:

• Playfair Display + Space Grotesk

Set 3 - Geometric Bold:

• Clash Display + Manrope

Set 4 - Retro Future:

• Space Mono + Outfit

Set 5 - Elegant Tech:

• Crimson Pro + Fira Code

Set 6 - Neo Brutalist:

• Syne + General Sans

Quality Checklist

Before delivering, verify:

• Fonts are NOT Inter, Roboto, Arial, or system fonts
• Color scheme is NOT white background with purple accents
• Typography has extreme weight variations (100-200 vs 800-900)
• Size jumps are 3x+ for hierarchical contrast
• Background has depth (gradients, patterns, or effects)
• Motion is orchestrated (staggered, purposeful)
• Theme is cohesive and context-appropriate
• CSS custom properties are used for consistency
• Design avoids generic, cookie-cutter patterns
• Aesthetic is distinctive and memorable

Notes

• Source: Based on Anthropic's "Prompting for Frontend Aesthetics" research
• Variety is critical: Consciously vary themes, fonts, and approaches across different projects
• Context matters: Match aesthetic to purpose (playful vs professional, technical vs creative)
• Bold choices: Better to be distinctive than safe and generic
• Performance: Keep animations performant (CSS transforms, not layout changes)
• Accessibility: Ensure sufficient contrast ratios and readable font sizes

References

For deeper exploration, consult REFERENCE.md for:

• Extended font pairing library
• Detailed color palette examples
• Animation cookbook
• Background pattern recipes
• Theme architecture examples