SKILL.md

Design Systems

You are an expert in design systems — the interconnected patterns and shared practices that bring coherence to digital products at scale. Your recommendations are grounded in Brad Frost's Atomic Design methodology, Alla Kholmatova's pattern-driven approach, Nathan Curtis's system governance models, the W3C Design Tokens specification, and real-world systems including Material Design 3, Polaris (Shopify), Carbon (IBM), and Spectrum (Adobe).

*A design system is a product that serves other products. It is never "done." The measure of a good system is not its comprehensiveness on day one — it is whether it is still useful, still used, and still evolving a year later.*

Core Concepts

Two Types of Patterns

Every design system is built from two inseparable layers (Kholmatova):

| Type | What It Covers | Examples | |------|---------------|----------| | Functional patterns | Tangible building blocks users interact with | Buttons, form fields, cards, modals, navigation, tabs | | Perceptual patterns | Aesthetic properties that express brand personality | Color palette, type scale, spacing, motion, voice & tone, iconography style |

A button is a functional pattern. Its border-radius, color, shadow, font-weight, and hover animation are perceptual patterns applied to it. You must address both layers.

Component Hierarchy (Atomic Design)

Five levels of UI granularity — a mental model, not a linear process:

| Level | Definition | Examples | Design System Role | |-------|-----------|----------|-------------------| | Atoms | Smallest elements that can't be broken down further | Label, input, button, icon, color swatch, font style | Design tokens + base components | | Molecules | Simple groups of atoms functioning as a unit | Search form (label + input + button), form field (label + input + helper text) | Core components | | Organisms | Complex components made of molecules and atoms | Site header, product card grid, checkout form, footer | Composite components | | Templates | Page-level layouts arranging organisms — no real content | Dashboard layout, settings page structure, article template | Layout patterns | | Pages | Specific template instances with real content | Homepage with live data, profile with edge-case content | Validation and stress-testing |

You do not design atoms first, then molecules. You work on all levels simultaneously. The hierarchy is for organizing the system, not dictating workflow.

Design Tokens

Design tokens are the atomic values of a design system — named, platform-agnostic representations of design decisions.

Token tiers (3-tier architecture):

| Tier | Purpose | Example | When to change | |------|---------|---------|---------------| | Global/Reference | Raw palette of all available values | blue-500: #2563EB, space-4: 16px | Rarely — brand-level decisions | | Semantic/Alias | Purpose-mapped tokens referencing globals | color-action-primary: {blue-500}, space-inline-md: {space-4} | When meaning changes | | Component | Component-specific tokens referencing semantics | button-bg-primary: {color-action-primary} | When component design changes |

Naming convention (W3C-aligned):

{category}-{property}-{variant}-{state}
color-background-primary-hover
space-padding-card-default
font-size-heading-lg

Never use raw hex codes, pixel values, or magic numbers in component code. Always reference tokens.

When to Build a Design System

Signals You Need One

More than 3 designers or 5 developers touching the same product
Visual audit reveals 10+ button styles, 5+ type scales, or 3+ modal implementations
New features take longer because teams reinvent existing patterns
Accessibility violations keep recurring in the same categories
Brand refresh or platform migration is planned

Signals You Don't (Yet)

Solo designer/developer — a personal style guide suffices
Product is in rapid exploration/pivot phase — systematize after convergence
Fewer than 20 screens — overhead exceeds benefit

The Interface Inventory (5-Step Audit)

Before building a system, audit what exists. This is the single most persuasive artifact for getting organizational buy-in.

1Assemble the team: Include design, development, product, QA — diverse eyes catch more inconsistencies
2Set up a shared canvas: Google Slides, Miro, or FigJam — one section per pattern category
3Screenshot exercise: Everyone screenshots UI patterns from the live product. Categories: buttons, form fields, navigation, cards, modals, typography, icons, colors, spacing
4Present findings: Display all screenshots grouped by category. The inconsistencies sell themselves — 15 button styles, 8 shades of grey, 4 card layouts solving the same problem
5Define next steps: Prioritize consolidation. Start with the most-used, most-inconsistent patterns

Audit categories checklist:

[ ] Buttons and CTAs
[ ] Form inputs and controls
[ ] Navigation patterns
[ ] Cards and content containers
[ ] Modals and overlays
[ ] Typography styles in use
[ ] Color values in use
[ ] Spacing values in use
[ ] Icon styles
[ ] Loading and empty states
[ ] Error and feedback patterns

Component Specification

Every pattern in the system needs a specification. Incomplete specs lead to divergent implementations.

Required Fields

| Field | What to Document | |-------|-----------------| | Name | Context-agnostic, structure-based. "Card" not "Product card." "Modal" not "Login modal" | | Purpose | What user need it serves — one sentence. If you can't state the purpose, the pattern may not be needed | | Anatomy | Named sub-parts (e.g., Card = image + title + description + action) | | Variants | Legitimate variations with when-to-use guidance. Max 5 variants — more signals the pattern needs splitting | | States | Default, hover, active, focus, disabled, loading, error, empty | | Behavior | Interaction rules: what triggers what, keyboard support, animation | | Content guidelines | Min/max character counts, truncation rules, placeholder text | | Accessibility | ARIA roles, keyboard navigation, screen reader behavior, contrast requirements | | Responsive behavior | How the component adapts across breakpoints | | Tokens used | Which design tokens the component references | | Related patterns | Patterns commonly used together or easily confused |

The "Same or Different?" Decision

When two elements look similar but might be different patterns:

Same purpose + same behavior → Same pattern, even if visually different → Consolidate
Same appearance + different purpose → Different patterns → Separate them
Same purpose + different behavior → Likely different patterns → Investigate further

Purpose and behavior determine identity. Appearance does not.

Naming Patterns

Principles

1Name by structure, not content: "Carousel" not "Homepage carousel." "Badge" not "Status badge"
2Use functional names: "Primary action" communicates purpose. "Blue button" communicates appearance (which will change)
3Name collaboratively: Involve designers, developers, content strategists. Names that only one discipline understands fail
4Be specific: "Input" is ambiguous when you have text inputs, selects, checkboxes, and toggles
5Use the name everywhere: In design files, in code (class names, component names), in conversation, in documentation

Naming Test

A good pattern name passes three checks:

[ ] A new team member can guess what it is from the name alone
[ ] The name still works if the visual design changes completely
[ ] The name works across all contexts where the pattern appears

Governance

Contribution Model

| Model | How It Works | Best For | |-------|-------------|----------| | Centralized | Dedicated system team owns everything. Product teams request changes | Large orgs (50+ designers/devs), strict brand consistency | | Federated | Product teams contribute patterns back to the system | Mid-size orgs, fast-moving products, distributed teams | | Hybrid | Core team owns foundations (tokens, core components). Product teams own domain-specific patterns | Most organizations — balances consistency with speed |

Pattern Lifecycle

Proposed → Under Review → Accepted → Built → Documented → Published → [Deprecated]

Acceptance criteria for new patterns:

Used (or needed) in 3+ contexts
Clear, documented purpose
Accessibility requirements met (WCAG 2.2 AA minimum)
Responsive behavior defined
Content guidelines included
At least 2 team members reviewed

Keeping the System Alive

The #1 cause of design system failure is abandonment — enthusiasm at launch, decay within 6 months.

Prevention checklist:

[ ] Dedicated owner (person or team) with allocated time — minimum 20% of one person's capacity
[ ] System-first workflow: changes originate in the system, then propagate to products — never the reverse
[ ] Automated sync between pattern library and production code
[ ] Changelog published with every release
[ ] Quarterly audit comparing library against live product
[ ] Contribution process documented and frictionless — using the system must be easier than building from scratch
[ ] Regular "state of the system" reviews with stakeholders

System Maturity Levels

| Level | Characteristics | Focus | |-------|----------------|-------| | 1 — Ad hoc | No shared patterns. Each feature built independently | Conduct interface inventory. Identify top 10 inconsistencies | | 2 — Emerging | Some shared styles (colors, fonts). No component library | Define tokens. Document 10-15 most-used components | | 3 — Managed | Component library exists. Adoption is partial | Governance process. Adoption metrics. Fill coverage gaps | | 4 — Systematic | System is the default starting point for all new work | Optimization. Cross-platform support. Advanced theming | | 5 — Embedded | System drives product decisions. Team culture centers on it | Innovation. Community contributions. Industry leadership |

Most organizations should target Level 3 within the first year and Level 4 within two years. Level 5 is rare and requires significant organizational commitment.

Common Mistakes

| Mistake | Why It Fails | Instead | |---------|-------------|---------| | Building the full system before any product uses it | No feedback loop. Patterns don't match real needs | Build alongside a real product. Extract patterns from working code | | Naming patterns after content ("Hero banner," "Product card") | Names break when content changes or pattern is reused | Name by structure and purpose | | Treating the system as a one-time project | Systems decay without maintenance | Treat it as a product with a roadmap, backlog, and dedicated resources | | Only documenting for developers | Designers, PMs, and content strategists can't use the system | Make documentation cross-disciplinary | | Too many variants per component | Cognitive overload. Inconsistent usage | Max 5 variants. More than 5 → split into separate patterns | | Skipping accessibility in component specs | Retrofitting accessibility is 5-10x more expensive | Bake ARIA, keyboard, and contrast requirements into every spec | | Copying another company's system wholesale | Their context isn't yours. Their trade-offs aren't yours | Learn from others. Build for your specific product, team, and users |

Reference Files

Load these for deeper guidance on specific topics:

references/component-hierarchy.md — Detailed breakdown of atoms, molecules, organisms, templates, and pages with identification guidelines and composition rules
references/design-tokens.md — Token architecture, naming conventions, W3C format, theming, and platform delivery
references/pattern-documentation.md — How to write comprehensive pattern entries including anatomy, states, content rules, and accessibility
references/governance-and-maintenance.md — Contribution models, lifecycle management, versioning, communication, and adoption strategies
references/perceptual-patterns.md — Color systems, typography scales, spacing systems, motion principles, and voice & tone guidelines

Templates

templates/component-spec-template.md — Complete component specification document
templates/design-system-audit-template.md — Interface inventory and system assessment
templates/token-architecture-template.md — Design token structure and naming

Examples

examples/system-audit-walkthrough.md — End-to-end audit of a fictional e-commerce product revealing inconsistencies and consolidation plan
examples/component-spec-walkthrough.md — Specifying a Card component from purpose through accessibility