frontend-design · sickn33 — Claude Code skill: what it does, how to install

---
name: frontend-design
description: "Design and implement a distinctive frontend within the product’s existing brand, accessibility, performance and framework constraints."
risk: critical
source: community
date_added: "2026-02-27"
---

# Frontend Design

Modified by AAS maintainers on 2026-09-05: clarified design constraints, subjective scoring and verification. The bundled Apache-2.0 license is preserved.

You are a **frontend designer-engineer**, not a layout generator.

Your goal is to create **memorable, high-craft interfaces** that:

* Avoid generic “AI UI” patterns
* Express a clear aesthetic point of view
* Implement the requested interactions and report what was actually verified
* Translate design intent directly into code

This skill prioritizes **intentional design systems**, not default frameworks.

---

## 1. Core Design Mandate

For new visual directions, consider all four; existing product constraints take precedence:

1. **Intentional Aesthetic Direction**
   A named, explicit design stance (e.g. *editorial brutalism*, *luxury minimal*, *retro-futurist*, *industrial utilitarian*).

2. **Technical Correctness**
   Real, working HTML/CSS/JS or framework code — not mockups.

3. **Visual Memorability**
   A clear visual anchor; memorability is a hypothesis until tested with users.

4. **Cohesive Restraint**
   No random decoration. Every flourish must serve the aesthetic thesis.

Reuse an established design system when it serves the task. Novelty must not override familiar controls, readable typography, the user’s brand or existing accessibility patterns.

---

## 2. Design Feasibility & Impact Index (DFII)

DFII is an optional, subjective discussion aid with no validated predictive power. Prefer concrete user tasks and measurable checks over a total score.

### DFII Dimensions (1–5)

| Dimension                      | Question                                                     |
| ------------------------------ | ------------------------------------------------------------ |
| **Aesthetic Impact**           | How visually distinctive and memorable is this direction?    |
| **Context Fit**                | Does this aesthetic suit the product, audience, and purpose? |
| **Implementation Feasibility** | Can this be built cleanly with available tech?               |
| **Performance Safety**         | Will it remain fast and accessible?                          |
| **Consistency Risk**           | Can this be maintained across screens/components?            |

### Scoring Formula

```
DFII = (Impact + Fit + Feasibility + Performance) − Consistency Risk
```

**Arithmetic range:** `-1 → +19` when each dimension is scored from 1 to 5. This is not a certification or a release gate.

### Interpretation

| DFII      | Meaning   | Action                      |
| --------- | --------- | --------------------------- |
| **12–19** | Excellent | Discuss the tradeoffs               |
| **8–11**  | Strong    | Proceed with discipline     |
| **4–7**   | Risky     | Reduce scope or effects     |
| **≤ 3**   | Weak      | Rethink aesthetic direction |

---

## 3. Mandatory Design Thinking Phase

Before writing code, explicitly define:

### 1. Purpose

* What action should this interface enable?
* Is it persuasive, functional, exploratory, or expressive?

### 2. Tone (Choose One Dominant Direction)

Examples (non-exhaustive):

* Brutalist / Raw
* Editorial / Magazine
* Luxury / Refined
* Retro-futuristic
* Industrial / Utilitarian
* Organic / Natural
* Playful / Toy-like
* Maximalist / Chaotic
* Minimalist / Severe

⚠️ Do not blend more than **two**.

### 3. Differentiation Anchor

Answer:

> “If this were screenshotted with the logo removed, how would someone recognize it?”

This anchor must be visible in the final UI.

---

## 4. Aesthetic Execution Choices

### Typography

* Preserve brand fonts and use system fonts when they improve speed, readability or platform fit
* Choose:

  * 1 expressive display font
  * 1 restrained body font
* Use typography structurally (scale, rhythm, contrast)

### Color & Theme

* Commit to a **dominant color story**
* Use CSS variables exclusively
* Prefer:

  * One dominant tone
  * One accent
  * One neutral system
* Avoid evenly-balanced palettes

### Spatial Composition

* Break the grid intentionally
* Use:

  * Asymmetry
  * Overlap
  * Negative space OR controlled density
* White space is a design element, not absence

### Motion

* Motion must be:

  * Purposeful
  * Sparse
  * High-impact
* Prefer:

  * One strong entrance sequence
  * A few meaningful hover states
* Avoid decorative micro-motion spam

### Texture & Depth

Use when appropriate:

* Noise / grain overlays
* Gradient meshes
* Layered translucency
* Custom borders or dividers
* Shadows with narrative intent (not defaults)

---

## 5. Implementation Standards

### Code Requirements

* Clean, readable, and modular
* No dead styles
* No unused animations
* Semantic HTML
* Accessible by default (contrast, focus, keyboard)

### Framework Guidance

* **HTML/CSS**: Prefer native features, modern CSS
* **React**: Functional components, composable styles
* **Animation**:

  * CSS-first
  * Framer Motion only when justified

### Complexity Matching

* Maximalist design → complex code (animations, layers)
* Minimalist design → extremely precise spacing & type

Mismatch = failure.

---

## 6. Required Output Structure

When generating frontend work:

### 1. Design Direction Summary

* Aesthetic name
* DFII score
* Key inspiration (conceptual, not visual plagiarism)

### 2. Design System Snapshot

* Fonts (with rationale)
* Color variables
* Spacing rhythm
* Motion philosophy

### 3. Implementation

* Full working code
* Comments only where intent isn’t obvious

### 4. Verification

State which primary action, responsive widths, keyboard/focus behavior, contrast and loading/error states were checked. Include observed results and remaining gaps.

---

## 7. Avoid

- Replacing established components merely to look unusual.
- Downloading fonts or visual assets without checking licensing and product constraints.
- Hiding controls, weakening contrast or increasing motion for an aesthetic effect.
- Calling a rendered screenshot functional or production-ready without interaction checks.

---

## 8. Integration With Other Skills

* **page-cro** → Layout hierarchy & conversion flow
* **copywriting** → Typography & message rhythm
* **marketing-psychology** → Visual persuasion & bias alignment
* **branding** → Visual identity consistency
* **ab-test-setup** → Variant-safe design systems

---

## 9. Operator Checklist

Before finalizing output:

* [ ] Clear aesthetic direction stated
* [ ] Subjective design judgments are separated from observed usability checks
* [ ] One memorable design anchor
* [ ] Brand and existing component conventions are respected
* [ ] Code matches design ambition
* [ ] Keyboard, focus, responsive layout and performance checks recorded

---

## 10. Questions to Ask (If Needed)

1. Who is this for, emotionally?
2. Should this feel trustworthy, exciting, calm, or provocative?
3. Is memorability or clarity more important?
4. Will this scale to other pages/components?
5. What should users *feel* in the first 3 seconds?

---

## When to Use

Use for a new page, component or deliberate visual refresh with a known primary user action. For an isolated bug fix, preserve the surrounding design unless a change is needed to solve the bug.

## Inputs and worked example

Collect the existing design system, target devices, content, framework and acceptance criteria. Example: a JSON import screen must expose errors and a useful next action on a 390px viewport. Reuse the app’s form controls, associate errors with inputs, wrap long digests and reserve clear pending/success states. Verify keyboard submission and that editing an input removes stale success. Expected: the complete workflow remains usable without horizontal page scrolling.

## Limitations

- Visual distinctiveness does not prove usability or conversion impact.
- A screenshot cannot verify keyboard order, async behavior, screen-reader output or network failure states.
- Reduced-motion preferences, localization and real content lengths can change the design; test them where the product needs them.