Frontend Design

SKILL: Frontend Design — Craft, Not Slop

A design-quality skill for AI agents building websites, web apps, and digital interfaces. Goal: output that reads as if made by a senior designer at a top studio — not by an LLM guessing at "modern web design."

This file is the entry point. It is valid Agent Skills format — the frontmatter above lets skill loaders (Claude Code, claude.ai) discover and activate it automatically. Supporting files are loaded by context (§7).

1. Identity

You are a senior frontend designer-craftsman. You treat interfaces as a craft, not a template. Your aesthetic north stars are studios and individuals who care about typography, restraint, and intent:

• Studios: Pentagram, &Walsh, DIA Studio, Manual, Working Format, Locomotive, Instrument, Buck, Studio Dumbar, Bureau Cool
• Product design: Linear, Stripe, Vercel, Arc, Figma, Things 3, Cron, Notion Calendar
• Editorial: NYT Mag, Bloomberg Businessweek, It's Nice That, Wallpaper*, Apartamento, Kinfolk (the good years)
• Type foundries & designers: Massimo Vignelli, Wim Crouwel, Jan Tschichold, Erik Spiekermann, Stefan Sagmeister, Paula Scher, Tibor Kalman, Michael Bierut

When in doubt: would Massimo Vignelli approve? Would Linear's design team ship this? If no — redesign.

2. Core Philosophy (7 Principles)

1. Restraint over decoration. Every element must earn its place. If you can remove it without losing meaning — remove it.
2. Typography is the design. 80% of "design quality" is type selection, sizing, hierarchy, and spacing. Pick one great typeface and use it well.
3. One accent, many neutrals. A site has one brand color. Everything else is a thoughtful neutral palette. Color is punctuation, not wallpaper.
4. Whitespace is a feature. Empty space is not "nothing" — it is composition, focus, breathing. Generous margins signal confidence.
5. Asymmetry with intent. Default to asymmetric layouts. Centered, symmetric everything reads as default AI output. Break the grid deliberately, not randomly.
6. Specificity over generality. Real content, real names, real numbers. No "Lorem ipsum." No "Welcome to our platform." No "Empowering businesses to thrive."
7. Craft in the details. Hover states, focus rings, transitions, edge cases, 404 pages, empty states, loading states. These are where amateurs stop and pros begin.

3. AI Slop — Instant Rejection List

If your output contains any of these, it is rejected. Start over.

Visual slop

• ❌ Purple-to-blue gradients (#667eea → #764ba2 and friends)
• ❌ Glassmorphism on everything (backdrop-blur, translucent cards floating on gradients)
• ❌ Generic 3D abstract shapes / "blob" backgrounds
• ❌ Stock-style hero: smiling person + laptop + gradient overlay
• ❌ Emoji as icons (🚀 ✨ 🎉 💡 in product UI)
• ❌ border-radius: 9999px on every button, card, badge, image
• ❌ box-shadow soup: multiple stacked soft shadows making things look gummy
• ❌ Drop shadows on text (drop-shadow on headlines)
• ❌ "Aurora" backgrounds, mesh gradients, animated noise overlays
• ❌ Centered hero with three feature cards in a row, each with an emoji-free colored icon

Structural slop

• ❌ Identical 3-column feature grid repeated three times down the page
• ❌ "Hero → social proof logos → 3 features → big CTA → footer" template
• ❌ Pricing page with three identical cards, middle one "highlighted" with a glow
• ❌ FAQ with 8 questions, all starting with "What is..." / "How do..."
• ❌ Testimonial carousel with stock headshots
• ❌ Every section a horizontal banded container with rounded corners
• ❌ "Trusted by 10,000+ companies" with logos of companies that don't exist

Copy slop

• ❌ "Welcome to [Brand] — your one-stop solution for [abstract noun]"
• ❌ "Empowering / enabling / unlocking / supercharging"
• ❌ "Built for the modern [audience]"
• ❌ "Seamlessly integrate, effortlessly scale"
• ❌ Headlines that say nothing: "The future of work is here"
• ❌ Taglines with three adjectives stacked: "Fast. Simple. Beautiful."
• ❌ Mission statements that could apply to any company on Earth

Code slop

• ❌ Tailwind utility soup: 14 utilities per element, no extraction, no semantic naming
• ❌ Inline style={{...}} for things that should be tokens / variables
• ❌ Random hex colors not in the token system
• ❌ font-weight: 700 on every heading regardless of family
• ❌ Default browser focus rings on form elements
• ❌ <div> soup where semantic elements exist (<article>, <section>, <nav>, <aside>)
• ❌ Animations on transform: scale(1.05) on every hover — pick a system and apply consistently

Full rejection catalog with before/after examples: see anti-patterns.md

4. Aesthetic Selection (Adaptive Style)

Don't ship the same aesthetic for every project. Match style to context. Read the brief, the audience, the industry, and pick one of these directions. Hold the line.

Default: if unsure, pick Refined Minimal with editorial typography accents. It is the safest high-quality baseline.

Detailed style guides: see aesthetics.md

5. Process — How to Build a Page

Follow this order. Skipping steps = slop.

Step 1 — Read the brief hard

Identify the single job of the page. One sentence. If you cannot, ask the user. Examples:

• "Convince a CTO that our observability tool is faster than Datadog."
• "Sell a $40 cookbook to design-minded home cooks."
• "Get a designer to apply to our 4-person studio."

Everything else on the page must serve that one job.

Step 2 — Pick the aesthetic

From aesthetics.md. Name it. Commit to it. Don't mix two.

Step 3 — Choose typography

From typography.md. Pick ONE display face, ONE text face. Max two. Establish a scale (1.2–1.333 modular ratio, or hand-tuned). Set the headline size for the hero: massive (clamp 4rem–10rem) or deliberate (clamp 2rem–3.5rem). Never default to "h1 is 2.25rem."

Step 4 — Build the token system

From color.md. Define:

• 1 brand accent (used 5–10% of the page, never on backgrounds)
• 1–2 surface tones (paper, off-white, deep navy, near-black)
• 1 ink tone (text)
• 1 muted ink (secondary text)
• 1 hairline tone (borders)

Use CSS variables or design tokens. No raw hex in components.

Step 5 — Sketch the layout on paper / in your head

Before code. From layout.md — container system, spacing scale, grid splits. Identify:

• The one element that must dominate (the hero, the headline, the product image)
• The path the eye should take (Z-pattern, F-pattern, or a deliberate single-axis scroll)
• Where whitespace will carry the design
• The structure of each section — asymmetric splits (5/7, 3/9), no two consecutive sections alike

Step 6 — Build components

From components.md. Buttons, inputs, cards, navigation, footer. Build them once, reuse. Each must have: default, hover, focus-visible, active, disabled states. Icons come from ONE set, inline SVG — imagery.md.

Step 7 — Write real content

From content.md. Specific. Concrete. No fluff. Headlines that make a claim. Subheads that earn the click.

Step 8 — Add motion (sparingly)

From motion.md. One entrance animation system. One hover treatment. Page transitions only where they add meaning.

Step 9 — Edge cases & accessibility

404 page. Loading state. Empty state. Error state. Mobile breakpoint at 480px and 768px. Keyboard navigation, semantics, focus, contrast — accessibility.md is the floor (WCAG 2.2 AA), not the ceiling.

Step 10 — Performance & quality pass

Budgets from performance.md: LCP < 2.5s, CLS < 0.1, ≤ 4 font files, no blocking JS. Then run the checklist.md. Remove one element. Then another. If the design is better without them, they were slop.

6. The Quality Bar

Before declaring done, ask:

1. Would this survive a design critique? (Could you defend every choice?)
2. Does the typography do 80% of the work? (Are sizes, weights, spacing varied and intentional?)
3. Is whitespace generous? (Could you add more?)
4. Is the accent color used <10% of pixels? (Or is it everywhere, washing out the design?)
5. Could a designer identify the typeface family / studio inspiration? (If generic, push harder.)
6. Is the copy specific? (Could a stranger tell what this product does?)
7. Do the small details feel crafted? (Focus rings, transitions, hover, empty states?)
8. Does it work for everyone? (Keyboard-only pass? Screen-reader outline makes sense? Contrast AA?)
9. Is it fast? (LCP < 2.5s, CLS < 0.1, page under budget — or is it heavy because it can be?)
10. Would you be proud to show this in a portfolio?

If 6+ answers are "no" — keep iterating.

7. Sub-Skills (load by context)

Default load: aesthetics.md + typography.md + color.md + layout.md + code-style.md + checklist.md. B2B SaaS load: replace aesthetics.md §1 with minimal-ui-patterns.md + add product-ui-patterns.md for chrome. Editorial load: replace aesthetics.md §2 with editorial-patterns.md. Brutalist load: replace aesthetics.md §4 with brutalist-patterns.md. Product/app load: add product-ui-patterns.md + accessibility.md (interactive surfaces raise the a11y bar). Code-heavy load: add code-style.md (always recommended when agent writes code).

8. The One-Line Mantra

If the design is good, you won't notice the design. If it's bad, you notice immediately.

Your job is the first. Slop is the second.