Frontend Design
SkillMediaGuide for creating distinctive, production-grade frontend interfaces. Covers visual design systems, typography, color, motion, spatial composition, and web interface standards. Use when designing UI, establishing design systems, or reviewing visual quality of frontend code.
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Connect ahel once, and every AI you use reads what you have installed.
Then ask your AI: use the Frontend Design skill
What this skill tells your AI
The instructions your AI receives, as published by s-hiraoku/vscode-sidebar-terminal in .agents/skills/frontend-design/SKILL.md and read by ahel’s review.
Create interfaces with intentional aesthetics and professional execution. Avoid generic "template" looks.
Design Process
Before writing code, answer these questions:
- Purpose — What problem does this interface solve? Who uses it?
- Tone — What aesthetic direction? (brutalist, luxury, playful, editorial, retro-futuristic, etc.)
- Constraints — Device targets, accessibility requirements, performance budget
- Signature — What single element makes this memorable?
Commit to a direction. Timid design is worse than bold design with flaws.
Typography
Font Selection
Avoid overused defaults. Choose typefaces that reinforce the interface's personality.
/* BAD: Generic, seen everywhere */
font-family: 'Inter', 'Roboto', 'Arial', sans-serif;
/* GOOD: Distinctive and paired intentionally */
--font-display: 'Instrument Serif', serif; /* headings */
--font-body: 'Satoshi', sans-serif; /* body text */
--font-mono: 'Berkeley Mono', monospace; /* code */
Typographic Details
/* Tabular numbers for aligned columns */
.data-cell { font-variant-numeric: tabular-nums; }
/* Balanced headings prevent widow words */
h1, h2, h3 { text-wrap: balance; }
/* Proper ellipsis character */
.truncate::after { content: '\2026'; } /* … not ... */
Handle text overflow deliberately:
/* Single line truncation */
.truncate { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
/* Multi-line clamping */
.clamp-3 { display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }
/* Flex children need min-w-0 for truncation to work */
.flex-child { min-width: 0; }
Color Systems
Theme Architecture
Build on CSS custom properties with clear semantic naming.
:root {
/* Primitives */
--gray-50: oklch(0.98 0.005 240);
--gray-900: oklch(0.15 0.01 240);
--accent: oklch(0.65 0.25 30);
/* Semantic tokens */
--color-bg: var(--gray-50);
--color-text: var(--gray-900);
--color-text-muted: oklch(0.55 0.01 240);
--color-border: oklch(0.88 0.005 240);
--color-accent: var(--accent);
--color-accent-hover: oklch(0.58 0.28 30);
}
@media (prefers-color-scheme: dark) {
:root {
--color-bg: var(--gray-900);
--color-text: var(--gray-50);
--color-text-muted: oklch(0.65 0.01 240);
--color-border: oklch(0.28 0.005 240);
}
}
Color Principles
- Commit to a palette — 1 dominant + 1–2 accents. Avoid 5-color rainbows.
- Use oklch — Perceptually uniform, better than hex/hsl for programmatic palettes.
- Contrast ratios — 4.5:1 minimum for body text, 3:1 for large text (WCAG AA).
Motion & Animation
Rules
- Respect user preference: Always honor
prefers-reduced-motion - Animate only
transformandopacity: These are GPU-composited, everything else triggers layout/paint - Never use
transition: all: List specific properties - Animations must be interruptible: User actions should cancel running animations
/* GOOD: Specific properties, respects user preference */
.card {
transition: transform 200ms ease-out, opacity 150ms ease-out;
}
@media (prefers-reduced-motion: reduce) {
.card { transition: none; }
}
High-Impact Moments
Focus animation budget on:
- Page transitions — Orchestrated staggered reveals
- State changes — Loading → content, collapsed → expanded
- Feedback — Button press, form submission confirmation
Skip: random hover effects on every element, scroll-jacking, decorative background animations.
Spatial Composition
Layout Principles
- Asymmetry is interesting — Perfectly centered grid layouts are predictable
- Intentional negative space — White space is a design element, not a mistake
- Grid-breaking elements — One element that overlaps or extends beyond the grid creates focus
- Diagonal flow — Eye movement along diagonals is more engaging than horizontal scan
Responsive Strategy
/* Fluid typography */
h1 { font-size: clamp(2rem, 5vw, 4rem); }
/* Container queries for component-level responsiveness */
.card-container { container-type: inline-size; }
@container (min-width: 400px) {
.card { grid-template-columns: 200px 1fr; }
}
Backgrounds & Atmosphere
Build visual depth through layered treatments:
/* Noise texture overlay */
.surface::after {
content: '';
position: absolute;
inset: 0;
background: url('/noise.svg');
opacity: 0.03;
pointer-events: none;
}
/* Gradient mesh */
.hero {
background:
radial-gradient(ellipse at 20% 50%, oklch(0.7 0.15 250 / 0.3), transparent 50%),
radial-gradient(ellipse at 80% 20%, oklch(0.7 0.2 30 / 0.2), transparent 50%),
var(--color-bg);
}
Images & Media
// Explicit dimensions prevent layout shift
<Image src={src} width={800} height={600} alt="Description" />
// Below-fold: lazy load
<Image src={src} loading="lazy" alt="..." />
// Above-fold: prioritize
<Image src={src} priority alt="..." />
// Decorative: empty alt
<Image src={pattern} alt="" aria-hidden="true" />
Interactive States
Every interactive element needs 4 states:
| State | Treatment |
|---|---|
| Default | Base appearance |
| Hover | Increased contrast or subtle shift |
| Focus | Visible ring via :focus-visible |
| Active/Pressed | Slight scale or color change |
| Disabled | Reduced opacity + cursor: not-allowed |
.button {
background: var(--color-accent);
transition: background 150ms ease-out, transform 100ms ease-out;
}
.button:hover { background: var(--color-accent-hover); }
.button:focus-visible { outline: 2px solid var(--color-accent); outline-offset: 2px; }
.button:active { transform: scale(0.98); }
Anti-Patterns
| Avoid | Instead |
|---|---|
| Inter/Roboto/Arial everywhere | Choose distinctive, project-appropriate typefaces |
| Purple gradient on white | Commit to a specific, cohesive palette |
| Uniform card grids | Vary sizes, add featured/hero cards |
| Shadows on everything | Use shadow purposefully for elevation hierarchy |
border-radius: 9999px on all elements | Match radius to content type and context |
| Identical hover effects | Tailor interaction feedback to element function |
Signals
- GitHub stars
- 21
- Forks
- 13
- Last commit
- Sep 2026
Advanced
- Catalog kind
- skill
- Gateway key
frontend-design-s-hiraoku- Source
- github.com/s-hiraoku/vscode-sidebar-terminal