transitions-dev

name

transitions-dev

description

Production-ready CSS transitions for web apps. Use when implementing notification badges, dropdowns, modals, panel reveals, page transitions, card resizes, number pop-ins, text swaps, icon swaps, success checks, avatar group hovers, error state shakes, search/input clear, skeleton loaders, shimmer text, sliding tabs, tooltips, staggered text reveals, card hover tilt, plus-to-menu morph, accordions, toasts, like buttons, learn-more hovers, checkbox checks, spinning counters, toggles, AI thinking states, reasoning streams, streaming text, matrix dot loaders, or banner stacking. Triggers on "add a transition", "animate the dropdown", "make the modal open smoothly", "swap icon", "page slide", "stagger animation", "open / close transition", "make it animate", "fade between", "success animation", "form error", "shake on invalid", "hover lift", "avatar stack hover", "clear the search", "skeleton loader", "loading shimmer", "shimmer text", "sliding tabs", "segmented control", "tooltip", "reveal text", "tilt card", "3D hover tilt", "cursor glare", "plus to menu", "FAB morph", "accordion", "collapsible", "expand / collapse", "disclosure", "toast", "snackbar", "like button", "heart animation", "learn more arrow", "checkbox", "check animation", "spinning counter", "odometer", "slot machine digits", "toggle", "switch", "thinking states", "AI status line", "agent reasoning", "reasoning stream", "streaming text", "stream words in", "matrix loader", "dot loader", "banner stack", "stacked toasts". Also "motion tokens", "scan for ad-hoc transitions", "replace hardcoded durations with motion tokens", "tokenize my animations", and the commands transitions reveal, transitions review, transitions apply, transitions refine.

Transitions.dev

Thirty-two portable CSS transitions, each namespaced under t-* selectors with semantic CSS custom properties. Drop-in: paste the snippet, wire the documented HTML hooks, done. No framework dependencies, no demo-specific markup, and every snippet ships a prefers-reduced-motion guard.

Quick reference

Transition	When to use	Reference
Card resize	Tween a container's width or height when its layout state changes.	01-card-resize.md
Number pop-in	Re-enter each digit with a blurred slide when a number updates.	02-number-pop-in.md
Notification badge	Slide a small badge onto a trigger and pop the dot.	03-notification-badge.md
Text states swap	Swap text in place with a blurred up-and-down transition.	04-text-states-swap.md
Menu dropdown	Open an origin-aware dropdown that grows from its trigger.	05-menu-dropdown.md
Modal open / close	Scale-up modal dialog with a softer scale-down on close.	06-modal.md
Panel reveal	Slide a panel into a region with a cross-blur.	07-panel-reveal.md
Page side-by-side	Slide between two side-by-side pages (list ↔ detail, step 1 ↔ step 2).	08-page-side-by-side.md
Icon swap	Cross-fade two icons in the same slot with blur and scale.	09-icon-swap.md
Success check	Compose fade + rotate + Y-bob + path stroke-draw to celebrate a completed action.	10-success-check.md
Avatar group hover	Distance-falloff lift on a row of items with a bouncy spring on return.	11-avatar-group-hover.md
Error state shake	Per-segment cubic-bezier shake with auto-reverting border + message.	12-error-state-shake.md
Input clear with dissolve	Fly-out + per-word streak when a text field is cleared.	13-input-clear-dissolve.md
Skeleton loader and reveal	Pulse a placeholder, then cross-fade + cross-blur to the loaded content.	14-skeleton-reveal.md
Shimmer text	Sweep a highlight band across muted text on a loop (pure CSS).	15-shimmer-text.md
Tabs sliding	Slide the active pill between tabs in a segmented control.	16-tabs-sliding.md
Tooltip open/close	Delayed fade+scale in, instant out (pure CSS).	17-tooltip.md
Texts reveal	Staggered blurred rise for stacked text lines, quiet fade out.	18-texts-reveal.md
Card hover tilt	Tilt a card in 3D toward the pointer with a cursor-tracked glare.	19-card-tilt.md
Plus to menu morph	Morph a circular trigger into the menu / panel it opens.	20-plus-menu-morph.md
Accordion expand	Grow / shrink a panel via grid-rows with a chevron flip.	21-accordion.md
Toast open / close	Rise a toast from below with fade + cross-blur, slower in than out.	22-toast.md
Like button	Fill a heart with a pop + particle burst on like.	23-like-button.md
Learn more hover	Slide the chevron and spread its arms into an arrow on hover.	24-learn-more-hover.md
Checkbox check	Fill the box, then stroke-draw the checkmark.	25-checkbox-check.md
Spinning counter	Spin slot-machine digit reels with vertical motion blur.	26-spinning-counter.md
Toggle	Travel the switch thumb with a double-bounce overshoot.	27-toggle.md
Thinking states	Shimmer a status line while it holds, then swap it to the next state.	28-thinking-states.md
Reasoning stream	Step an agent-reasoning transcript up two lines at a time on a loop.	29-reasoning-stream.md
Streaming text	Resolve streamed words one by one through a soft cross-blur.	30-streaming-text.md
Matrix dot loader	Pulse a 4×4 dot matrix in scan / twinkle / orbit / pulse patterns.	31-matrix-loader.md
Banner stacking	Stack banners like toasts — new ones rise in, older ones push back.	32-banner-stacking.md

Decision rules

When the user asks for a transition, match against the visible UI element first, then the verb:

• Trigger + small dot floating on top → notification badge.
• Trigger + surface that grows from it → dropdown (anchored, origin-aware) or modal (centered, no anchor).
• Surface that slides into a region of the page → panel reveal.
• Two screens, list ↔ detail or step 1 ↔ step 2 → page side-by-side.
• Element changes width or height → card resize.
• Element's text content changes in place → text states swap.
• Two icons in the same slot → icon swap.
• A number updates → number pop-in.
• Confirmation / success / "done" moment (checkmark, payment processed, file uploaded) → success check.
• Hovering an item in a horizontal stack (avatars, chips, segmented buttons, tag pills) → avatar group hover.
• Form validation error / "this is wrong" feedback (invalid field, wrong PIN, duplicate name) → error state shake.
• Clearing a text field (search box × button, filter reset) → input clear with dissolve.
• Placeholder that loads then swaps to real content (list row, card, profile header) → skeleton loader and reveal.
• In-progress / "thinking" text that should feel alive (loading label, streaming status) → shimmer text.
• Small horizontal set of mutually-exclusive options with a moving highlight (view switcher, segmented control, filter tabs) → tabs sliding.
• Hover/focus hint that appears over a trigger (icon tooltip, info bubble) → tooltip open / close.
• Stacked headline + supporting line entering with rhythm (hero copy, empty state, onboarding step) → texts reveal.
• Card / tile that should react in 3D to the pointer on hover (product card, cover art, membership card, with or without a light glare) → card hover tilt.
• Circular trigger that becomes the surface it opens (+ FAB grows into a menu / panel, compose button expands) → plus → menu morph. If the surface is a separate popover that merely grows from the trigger, use menu dropdown instead.
• Header with a collapsible body that grows / shrinks in height (settings group, FAQ, filter section, "show more", disclosure) → accordion expand.
• No clear match → fall back to transitions reveal and let the user pick. Don't guess.

If two transitions could fit, prefer the lower-overhead one (card resize over panel reveal, dropdown over modal, success check over a full modal celebration) unless the design clearly calls for the heavier surface. The success check is animation-only — if you also need to swap from a spinner to the check, pair it with icon swap.

Commands

The skill exposes four namespaced verbs the agent should recognise in addition to direct transition requests. Every command starts with transitions so the invocation never collides with verbs from other skills installed in the same project.

transitions reveal — list every transition

Trigger phrases: transitions reveal, "reveal the transitions", "list all transitions", "what transitions are in this skill", "show the transitions catalog".

Behaviour: print the thirty-two transitions as a numbered plain-text list — name, one-line summary, and the matching reference filename. Reuse the rows in ## Quick reference above; do not invent new copy. No project access.

transitions review — audit the project for fit

Trigger phrases: transitions review, "review my project", "audit my animations", "where would transitions.dev help", "find places to use this skill".

Behaviour:

1. Search the workspace for indicators: transition: declarations, @keyframes, hardcoded ms / s durations in style files, components matching the decision-rule patterns (modals, dropdowns, badges, search inputs, skeletons, tabs, tooltips, …).
2. For each hit, match against the decision rules and pick the single best-fit transition.
3. Output a numbered list grouped by file:
   • path/to/Component.tsx:L42 — looks like a dropdown opening, suggest menu-dropdown (05-menu-dropdown.md).
   • Skip ad-hoc transitions that already use a t-* class.
4. Do not edit anything. End with: "Run transitions apply on any line to install the suggested transition."

transitions apply — install the best-fit transition

Trigger phrases: transitions apply, "apply a transition here", "add the right transition", "install transitions-dev here", "fix the animation on this element".

Behaviour:

1. Read context: the currently-open file, the element nearest the cursor, surrounding CSS / JSX. If the user named a transition explicitly (e.g. transitions apply menu-dropdown), use it.
2. Run the decision rules from ## Decision rules on that context and pick one transition. If two could fit, prefer the lower-overhead one (same tie-breaker the existing rules use).
3. Surface a one-line proposal: "I'd apply menu-dropdown here because the element opens from a trigger and is anchored. Confirm to install?".
4. On confirmation, follow the existing five-step procedure in ## Output format verbatim (root block, snippet, hooks, reduced-motion guard, JS orchestration if needed).
5. If the agent can't pick a single transition with confidence, fall back to transitions reveal and ask the user to choose.

transitions refine — replace ad-hoc motion with the motion tokens

Trigger phrases: transitions refine, "refine my transitions", "scan for ad-hoc transitions", "replace hardcoded durations with motion tokens", "tokenize my animations", "tune the durations / easing", "audit my custom keyframes", "make the timing consistent", "align to the motion tokens".

Behaviour:

1. Scan the whole project (not just dedicated stylesheets — also inline style= / CSS-in-JS, styled-components, <style> blocks, Tailwind arbitrary values like duration-[300ms]) for ad-hoc motion: transition / animation shorthands and longhands, custom @keyframes blocks, hardcoded durations (…ms / …s), easing (cubic-bezier(...) or keywords), translate distances (px), scale(...), and blur(...).
2. For each value, infer what the motion does (modal close, dropdown open, tooltip, badge appear, text reveal, page slide, shake, …) from the surrounding selectors / component plus the ## Decision rules. For a @keyframes block, read the animation that drives it and judge the keyframes' own duration/easing.
3. The key decision point is usage, not the raw number. Look the inferred usage up in ## Motion tokens and suggest the token whose documented usage matches — only when the usages line up. A 300ms modal close maps to --duration-quick because both are "modal close", even though the numbers differ. If a value's usage matches no token's usage, list it as no matching token usage and leave it untouched — never force a swap just because a number is close.
4. Output a numbered list grouped by file, showing only values that should change, each as path/to/Component.css:L42 — modal close: 300ms → var(--duration-quick) (150ms), ease → var(--ease-smooth-out). For keyframe-driven motion, suggest the token for the driving animation's duration/easing.
5. Do not edit anything. End with: "Confirm any line to apply the change, or run transitions apply to install a full transition instead."

Motion tokens

The shared motion scale behind the thirty-two transitions — the same tokens the transitions.dev Motion tokens tab exposes. They ship at the top of _root.css, so once it's imported you can reference any of them as var(--…) (e.g. transition: transform var(--duration-fast) var(--ease-smooth-out)).

transitions refine maps each existing value to a usage below, then suggests the token to reference. Match on usage, not on the raw number — a 300ms modal close still maps to --duration-quick (150ms).

Durations

Token	Value	Usage
--duration-stagger	40ms	per-item stagger offset
--duration-micro	80ms	tooltip/path delay, shake segment, large stagger
--duration-quick	150ms	modal/dropdown close, text swap, tooltip appear
--duration-fast	250ms	icon swap, dropdown/modal open, tabs sliding, page slide
--duration-medium	350ms	panel close, toast close
--duration-slow	400ms	panel open, skeleton content reveal, input clear
--duration-very-slow	500ms	emphasis moments, badge appear, text reveal, success check

Easings

Token	Value	Usage
--ease-smooth-out	cubic-bezier(0.22, 1, 0.36, 1)	modal/dropdown/panel open + close, page slide, resize, position change
--ease-in-out	ease-in-out	icon swap, text swap, text reveal, skeleton reveal
--ease-out	ease-out	tooltip open / close
--ease-linear	linear	shimmer, skeleton pulse, spinner
--ease-bounce	cubic-bezier(0.34, 1.36, 0.64, 1)	badge pop open
--ease-bounce-strong	cubic-bezier(0.34, 3.85, 0.64, 1)	bouncy hover-out (avatar return)

Distances

Token	Value	Usage
--distance-micro	4px	text swap