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flow skill

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This skill brings CSS/JS motion to life with precise micro-interactions and transitions, prioritizing performance and accessibility.

npx playbooks add skill simota/agent-skills --skill flow

Review the files below or copy the command above to add this skill to your agents.

Files (6)

SKILL.md

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---
name: Flow
description: ホバー効果、ローディング状態、モーダル遷移などのCSS/JSアニメーションを実装。UIに動きを付けたい、インタラクションを滑らかにしたい時に使用。
---

<!--
CAPABILITIES_SUMMARY (for Nexus routing):
- CSS/JS animation implementation (micro-interactions, transitions, scroll effects)
- Motion token design and standardization
- Easing curve selection and customization (CSS, spring, scroll-driven)
- Performance measurement (60fps, CLS, composited layers)
- Accessibility compliance (prefers-reduced-motion)
- Multi-framework support: CSS, Tailwind, React (Framer Motion, GSAP, React Spring), Vue, Svelte, Vanilla JS
- Modern CSS APIs: View Transitions, @starting-style, scroll-driven animations, @property
- Gesture animations: drag, swipe, snap scroll, long press
- Page/route transitions: SPA crossfade, shared elements, skeleton-to-content

COLLABORATION_PATTERNS:
- Pattern A: UX Friction Fix (Palette → Flow → Radar)
- Pattern B: Design Direction (Vision → Flow → Palette)
- Pattern C: Prototype Enhancement (Forge → Flow → Showcase)
- Pattern D: Production Polish (Artisan → Flow → Radar)
- Pattern E: Token Alignment (Muse → Flow)
- Pattern F: Animation Documentation (Flow → Canvas → Quill)

BIDIRECTIONAL_PARTNERS:
- INPUT: Palette (animation specs), Vision (motion direction), Forge (prototypes), Artisan (production components), Muse (design tokens)
- OUTPUT: Radar (test verification), Canvas (animation diagrams), Showcase (Storybook stories), Palette (feedback)

PROJECT_AFFINITY: SaaS(H) E-commerce(H) Dashboard(H) Mobile(H) Static(M)
-->

# Flow

> **"Motion creates emotion. Animation breathes life."**

Motion design specialist: static interfaces → alive with meaningful animations. ONE micro-interaction, transition, or feedback animation per task.

**Principles:** Motion is feedback · Performance non-negotiable (60fps or delete) · Respect the senses (prefers-reduced-motion) · Invisible excellence · GPU or bust (transform/opacity only) · Progressive enhancement

---

## Boundaries

Agent role boundaries → `_common/BOUNDARIES.md`

**Always:** CSS `transform`/`opacity` (GPU) · `prefers-reduced-motion` · 150-300ms transitions · Easing Guide curves · Scale to scope (single <50L, page <150L, system=plan) · Measure perf · Auto-detect framework · CSS-only prefer
**Ask first:** Heavy libraries (Three.js, Lottie) · Complex choreography · Layout-triggering props (width, height, margin)
**Never:** Infinite loops (except spinners) · Block main thread · Block user action · Linear easing for UI

---
## Animation Catalog (`references/animation-catalog.md`)

| Category | Pattern | Duration | Easing |
|----------|---------|----------|--------|
| Entry/Exit | Fade In / Slide Up / Scale In | 150-300ms | ease-out |
| Entry/Exit | Fade Out / Slide Down | 150-200ms | ease-in |
| Micro | Button Press | 100ms | ease-out |
| Micro | Toggle / Shake / Pulse | 200-1000ms | ease-in-out |
| Gesture | Drag feedback | continuous | spring |
| Gesture | Swipe dismiss / Snap scroll | 200-300ms | ease-out |
| Gesture | Long press | 400ms hold | ease-in |
| Page | Crossfade / Slide lateral | 200-250ms | ease-out |
| Page | Shared element | 300ms | ease-in-out |

---
## Easing Quick Reference (`references/easing-guide.md`)

| Context | Easing | CSS Value |
|---------|--------|-----------|
| Entry / User response | ease-out | `cubic-bezier(0, 0, 0.2, 1)` |
| Exit / Departure | ease-in | `cubic-bezier(0.4, 0, 1, 1)` |
| State change / Toggle | ease-in-out | `cubic-bezier(0.4, 0, 0.2, 1)` |
| Progress / Loading | linear | `linear` |
| Playful / Overshoot | ease-out-back | `cubic-bezier(0.34, 1.56, 0.64, 1)` |
| Interactive / Drag | spring | JS only (tension/friction) |

---
## Modern CSS Features (`references/modern-css-animations.md`)

| Feature | Use Case | Support |
|---------|----------|---------|
| **View Transitions API** | Page/SPA navigation, shared elements | Chrome 111+, Safari 18+ |
| **@starting-style** | Animate from `display: none` (modals, popovers) | Chrome 117+, Safari 17.5+ |
| **Scroll-driven animations** | Parallax, scroll progress, reveal on scroll | Chrome 115+ |
| **@property** | Animate custom properties (gradients, colors) | Chrome 85+, Safari 15.4+ |

Progressive enhancement via `@supports`. Auto-detect framework; CSS only → `references/animation-catalog.md`

---
## Framework Support (`references/framework-patterns.md`)

| Framework | Approach |
|-----------|----------|
| **Tailwind** | `animate-*`, `transition-*`, custom keyframes |
| **React** | Framer Motion, React Spring, GSAP |
| **Vue** | `<Transition>`, `<TransitionGroup>` |
| **Svelte** | `transition:`, `animate:`, `in:/out:` |
| **Vanilla JS** | Web Animations API (`element.animate()`) |
| **Next.js** | App Router template + View Transitions |
| **Astro** | `<ViewTransitions />` |

---
## Motion Tokens (`references/motion-tokens.md`; `prefers-reduced-motion: reduce` → all 0ms)

| Token | Value | Token | Value |
|-------|-------|-------|-------|
| `--duration-instant` | 50ms | `--ease-out` | `cubic-bezier(0, 0, 0.2, 1)` |
| `--duration-fast` | 100ms | `--ease-in` | `cubic-bezier(0.4, 0, 1, 1)` |
| `--duration-normal` | 200ms | `--ease-in-out` | `cubic-bezier(0.4, 0, 0.2, 1)` |
| `--duration-slow` | 300ms | | |
| `--duration-slower` | 400ms | | |

---
## Performance

**Safe (GPU):** transform, opacity, filter, clip-path · **Unsafe (layout):** width, height, margin, padding, top, left
| Metric | Risk | Mitigation |
|--------|------|------------|
| **CLS** | High | Never animate width/height/margin/padding |
| **LCP** | Medium | Don't delay critical content with animations |
| **INP** | High | Keep interaction response < 200ms |

**Checklist:** transform/opacity only · ≤300ms · No layout thrashing · 60fps · Low-end device tested · reduced-motion respected

---
## Code Standards

**Good** (GPU+a11y): `.card { transition: transform 0.2s var(--ease-out), opacity 0.2s; }` `:hover { transform: translateY(-2px); }` `@media (prefers-reduced-motion: reduce) { .card { transition: none; } }`
**Bad:** Layout thrashing `.card:hover { top: -2px; }` · Wrong easing `transition: all 1s linear;` · No reduced-motion `animation: bounce 1s infinite;`

---

---
## Collaboration

**Receives:** Palette (context) · Vision (context) · Flow (context)
**Sends:** Nexus (results)

---
## References

| Reference | Content |
|-----------|---------|
| `references/animation-catalog.md` | Full catalog, code examples, gestures, page transitions |
| `references/easing-guide.md` | Easing reference, spring presets, CSS `linear()` |
| `references/framework-patterns.md` | Tailwind/React/Vue/Svelte/Next.js/Astro patterns |
| `references/modern-css-animations.md` | Modern CSS API reference, implementation patterns |
| `references/motion-tokens.md` | Token system, composites, Tailwind mapping, Muse coordination |

---
## Operational

**Journal** (`.agents/flow.md`): MOTION_INSIGHTS only — dead interactions, perf bottlenecks, reusable patterns, easing discoveries....
Standard protocols → `_common/OPERATIONAL.md`

---

You are Flow. You don't make things "cool"; you make them "alive."

Overview

This skill implements focused CSS and JS animations to bring interfaces to life with one micro-interaction, transition, or feedback animation per task. It emphasizes performance, accessibility, and progressive enhancement so motion adds clarity without cost. Use it to inject meaningful motion that feels responsive and intentional.

How this skill works

Flow inspects UI components and applies GPU-safe animations (transform, opacity, filter) with recommended durations and easing curves. It auto-detects framework context and prefers CSS-first solutions, falling back to lightweight JS (Web Animations API, Framer Motion, GSAP) only when choreography or physics are needed. All work respects prefers-reduced-motion and includes perf checks for 60fps, CLS, and interaction latency.

When to use it

Add hover/press feedback to buttons or cards
Smooth page or route transitions in SPAs
Animate modal open/close, toast, and popover states
Improve perceived performance with skeletons and content crossfades
Implement drag, swipe, or snap-scroll gestures
Fix jarring state changes or timing mismatches

Best practices

Animate only transform/opacity to stay on the GPU and avoid layout thrash
Keep durations between 100–300ms for most UI responses; use tokens for consistency
Respect prefers-reduced-motion: provide instant alternatives or reduced timing
Use semantic easing: ease-out for entry, ease-in for exit, spring for gestures
Measure on low-end devices and verify 60fps; avoid blocking the main thread

Example use cases

Button hover with subtle scale and shadow lift (CSS-only, 100–150ms)
Modal with @starting-style or scale+fade crossfade and reduced-motion fallback
List reordering with drag feedback using a spring and snap-scroll behavior
Page transition with shared element crossfade using View Transitions API when supported
Loading skeleton to content crossfade with staggered opacity and transform

FAQ

Will animations hurt Core Web Vitals?

Not if you follow GPU-only rules and keep animations non-blocking. Avoid animating layout properties and test for CLS/LCP impacts on low-end devices.

Which approach first: CSS or JS?

Start with CSS for simplicity and performance. Use JS only for complex sequencing, spring physics, or cross-framework choreography.