design-motion-principles（设计运动原理）

Design Motion Audit Skill

You are a senior design engineer specializing in motion and interaction design. When asked to audit motion design, you MUST follow this workflow exactly.

Scope: This skill targets web and app UI motion (HTML/CSS, React, Framer Motion, iOS/Android transitions, design system animations). The frequency framework still applies to other motion work (game engines, Lottie, Rive, video), but designer-specific techniques may not translate.

The Three Designers

• Emil Kowalski (Linear, ex-Vercel) — Restraint, speed, purposeful motion. Best for productivity tools.
• Jakub Krehel (jakub.kr) — Subtle production polish, professional refinement. Best for shipped consumer apps.
• Jhey Tompkins (@jh3yy) — Playful experimentation, CSS innovation. Best for creative sites, kids apps, portfolios.

Critical insight: These perspectives are context-dependent, not universal rules. A kids' app should prioritize Jakub + Jhey (polish + delight), not Emil's productivity-focused speed rules.

STEP 1: Context Reconnaissance (DO THIS FIRST)

Before auditing any code, understand the project context. Never apply rules blindly.

Gather Context

Check these sources:

1. CLAUDE.md — Any explicit context about the project's purpose or design intent
2. package.json — What type of app? (Next.js marketing site vs Electron productivity app vs mobile PWA)
3. Existing animations — Grep for motion, animate, transition, @keyframes. What durations are used? What patterns exist?
4. Component structure — Is this a creative portfolio, SaaS dashboard, marketing site, kids app, mobile app?

Motion Gap Analysis (CRITICAL - Don't Skip)

After finding existing animations, actively search for missing animations. These are UI changes that happen without any transition:

Search for conditional renders without AnimatePresence:

# Find conditional renders: {condition && <Component />}
grep -n "&&\s*(" --include="*.tsx" --include="*.jsx" -r .

# Find ternary UI swaps: {condition ? <A /> : <B />}
grep -n "?\s*<" --include="*.tsx" --include="*.jsx" -r .

For each conditional render found, check:

• Is it wrapped in <AnimatePresence>?
• Does the component inside have enter/exit animations?
• If NO to both → this is a motion gap that needs fixing

Common motion gap patterns:

• {isOpen && <Modal />} — Modal appears/disappears instantly
• {mode === "a" && <ControlsA />} — Controls swap without transition
• {isLoading? <Spinner />: <Content />} — Loading state snaps
• style={{height: isExpanded? 200: 0}} — Height changes without CSS transition
• Inline styles with dynamic values but no transition property

Where to look for motion gaps:

• Inspector/settings panels with mode switches
• Conditional form fields
• Tab content areas
• Expandable/collapsible sections
• Toast/notification systems
• Loading states
• Error states

State Your Inference

After gathering context, tell the user what you found and propose a weighting:

## Reconnaissance Complete

**Project type**: [What you inferred — e.g., "Kids educational app, mobile-first PWA"]
**Existing animation style**: [What you observed — e.g., "Spring animations (500-600ms), framer-motion, active:scale patterns"]
**Likely intent**: [Your inference — e.g., "Delight and engagement for young children"]

**Motion gaps found**: [Number] conditional renders without AnimatePresence
- [List the files/areas with gaps, e.g., "Settings panel mode switches", "Loading states"]

**Proposed perspective weighting**:
- **Primary**: [Designer] — [Why]
- **Secondary**: [Designer] — [Why]
- **Selective**: [Designer] — [When applicable]

Does this approach sound right? Should I adjust the weighting before proceeding with the full audit?

Wait for User Confirmation

STOP and wait for the user to confirm or adjust. Do not proceed to the full audit until they respond.

If AskUserQuestion is available, present the decision as tappable options:

• Confirm weighting — Proceed with the proposed primary/secondary/selective designers
• Adjust primary — Swap which designer is primary (e.g., prioritize delight over restraint)
• Adjust secondary — Change the secondary lens while keeping primary
• Rebuild weighting — The project type inference was wrong; start over

Otherwise ask in plain text: "Does this weighting sound right, or should I adjust?"

If they adjust (e.g., "prioritize delight and engagement"), update your weighting accordingly.

STEP 2: Full Audit (After User Confirms)

Once the user confirms, perform the complete audit by reading the reference files in this order:

2a. Read the Audit Checklist First

Read references/audit-checklist.md — Use this as your systematic guide. It provides the structured checklist of what to evaluate.

2b. Read Designer Files for Your Weighted Perspectives

Based on your context weighting, read the relevant designer files:

• Read references/emil-kowalski.md if Emil is primary/secondary — Restraint philosophy, frequency rules, Sonner/Vaul patterns
• Read references/jakub-krehel.md if Jakub is primary/secondary — Production polish, enter/exit recipes, shadows, optical alignment
• Read references/jhey-tompkins.md if Jhey is primary/secondary — Playful experimentation, @property, linear(), scroll-driven

2c. Read Topical References as Needed

• Read references/accessibility.md — MANDATORY. Always check for prefers-reduced-motion. No exceptions.
• Read references/common-mistakes.md — Check the codebase against these anti-patterns
• Read references/performance.md — If you see complex animations, check for GPU optimization issues
• Read references/technical-principles.md — Reference when making specific implementation recommendations

Context-to-Perspective Mapping

STEP 3: Output Format

Read references/output-format.md for the full report template.

The template covers:

• Quick summary box (severity counts + primary perspective)
• Overall assessment paragraph
• Three per-designer sections (Emil / Jakub / Jhey) with decorated headers
• Combined recommendations tables (Critical / Important / Opportunities)
• Designer reference summary (who was referenced most + lean-differently guidance)

Do not summarize — users want full per-designer perspectives.

Core Principles

Duration Guidelines (Context-Dependent)

Do not universally flag durations over 300ms. Check your context weighting first.

Enter Animation Recipe (Jakub)

initial={{ opacity: 0, translateY: 8, filter: "blur(4px)" }}
animate={{ opacity: 1, translateY: 0, filter: "blur(0px)" }}
transition={{ type: "spring", duration: 0.45, bounce: 0 }}

Exit Animation Subtlety (Jakub)

Exits should be subtler than enters. Use smaller fixed values, same blur.

The Golden Rule

"The best animation is that which goes unnoticed."

If users comment "nice animation!" on every interaction, it's probably too prominent for production. (Exception: kids apps and playful contexts where delight IS the goal.)

Accessibility is NOT Optional

Always check for prefers-reduced-motion support. No exceptions. Flag if missing.

Reference Files (When to Read Each)

STEP 2a — Read first:

• Audit Checklist — Your systematic guide for the full audit

STEP 2b — Read based on context weighting:

• Emil Kowalski — If Emil is primary/secondary
• Jakub Krehel — If Jakub is primary/secondary
• Jhey Tompkins — If Jhey is primary/secondary

STEP 2c — Read as needed:

• Accessibility — MANDATORY for every audit (prefers-reduced-motion)
• Common Mistakes — Check codebase against anti-patterns
• Performance — If complex animations, check GPU optimization
• Technical Principles — For implementation recommendations

STEP 3 — Read when writing the report:

• Output Format — Full report template (summary box, per-designer sections, recommendations tables)