Frontend Design

Frontend Design

A frontend design skill for AI agents. Every UI you touch should feel hot, sleek, sexy, usable, fun, and addictive.

Core Philosophy

Design is not decoration. It's communication. Every pixel exists to serve the user's intent while making them feel something. The best interfaces are invisible — they get out of the way while being impossibly beautiful.

Principles:

• Clarity over cleverness — if it needs a tooltip, redesign it
• Motion with meaning — every animation tells a story
• Contrast is king — visual hierarchy through bold contrast, not clutter
• White space is not empty — it's breathing room
• Dark mode first — because we live in the future

Design Patterns

Cards

Cards are the atomic unit of modern UI. Rules:

• Subtle border, generous padding (1.25rem+)
• Hover state: slight lift (translateY -2px) + border glow
• Never more than 3 levels of text hierarchy per card
• Background should be 1-2 shades lighter than page bg

Buttons

• Primary: solid fill, bold, slight shadow
• Secondary: outlined, transparent bg
• Ghost: no border, text only, underline on hover
• Always include hover + active + focus states
• Min touch target: 44px

Forms

• Labels above inputs, never floating
• Generous input padding (0.875rem)
• Focus ring = accent color border, not browser default
• Error states: pink/red border + helper text below
• Success: green accent, brief animation

Layout Principles

Spacing Scale

Use a consistent spacing scale based on 0.25rem increments:

• xs: 0.25rem (4px)
• sm: 0.5rem (8px)
• md: 1rem (16px)
• lg: 1.5rem (24px)
• xl: 2rem (32px)
• 2xl: 3rem (48px)
• 3xl: 4rem (64px)

Grid

• Max content width: 1200px
• Side padding: 2rem (1rem mobile)
• Column gap: 1.5-2rem
• Mobile: single column, always

Typography

• Display: bold, tight letter-spacing (-0.02em)
• Body: 1rem, line-height 1.6
• Small: 0.875rem for metadata
• Handwriting fonts for personality moments
• Monospace for code, versions, hashes

Color System

Always define CSS variables. Never hardcode colors.

:root {
  --bg-primary: #faf6f0;      /* warm cream */
  --bg-secondary: #f0ebe3;
  --bg-card: #ffffff;
  --text-primary: #1a1a1a;
  --text-secondary: #555;
  --text-muted: #999;
  --border: rgba(0,0,0,0.08);
  --accent: #e84a5f;          /* rose */
  --accent-2: #4a90e2;        /* blue */
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
}

Dark mode: invert the bg scale, keep accent colors, increase border opacity slightly.

Animation

• Hover transitions: 0.2-0.25s ease
• Page transitions: 0.3s ease
• Never exceed 0.5s for UI animations
• Use transform and opacity only — no animating layout properties
• will-change: transform on frequently animated elements

Component Checklist

Before shipping any component, verify:

• Hover state defined
• Focus state defined (keyboard accessible)
• Active/pressed state
• Loading state (if async)
• Empty state (if data-driven)
• Error state (if can fail)
• Mobile layout (< 768px)
• Dark mode compatible

Anti-Patterns

Never do these:

• Fixed pixel widths on text containers
• !important in your CSS
• Z-index > 100 (symptom of stacking context chaos)
• Color without sufficient contrast (WCAG AA minimum)
• Hover-only interactions (mobile has no hover)
• outline: none without a replacement focus style

Trigger Phrases

Activate on:

• "Design a [component]"
• "Make this look better"
• "Review my UI"
• "Build a landing page"
• "How should I style [X]"
• Any request involving visual design, CSS, or component architecture