Jakubantalik / transitions.dev

transitions-dev

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.

View source Motion Interaction

Install

npx skills add https://github.com/Jakubantalik/transitions.dev --skill transitions-dev

Skeleton loader and reveal

When to use

A placeholder that loads then reveals real content — list rows, cards, profile headers. The skeleton pulses, then both layers cross-fade with a matching cross-blur. Bring your own bars / avatar / text; the skeleton stays in the same slot as the content so the swap is layout-free.

HTML usage

State:

Mount with .is-pulsing on the skeleton so it pulses --pulse-count times.
When data arrives, add .is-revealed to .t-skel — the skeleton fades out + blurs and the content fades in + un-blurs over --reveal-dur.
To replay the loading state without animating the reverse: add .is-resetting to .t-skel, remove .is-revealed, force a reflow, then drop .is-resetting.

Bring your own avatar / text / wrapping. The skeleton stays in the same flex slot as the content so the swap is layout-free.

Tunable variables

Variable	Default	Notes
`--pulse-dur`	`1000ms`	sourced from `--p14-pulse-dur`
`--pulse-count`	`1`	sourced from `--p14-pulse-count`
`--pulse-min`	`0.5`	sourced from `--p14-pulse-min`
`--reveal-dur`	`400ms`	sourced from `--p14-reveal-dur`
`--reveal-blur`	`2px`	sourced from `--p14-reveal-blur`
`--reveal-ease`	`ease-in-out`	sourced from `--p14-reveal-ease`

The :root defaults below match the live tuning on transitions.dev. Drop them into your global stylesheet once — every transition in this skill reads from semantic names like these, so multiple transitions can share a single :root block.

CSS

css

/* The wrap stacks two layers on the same coordinates. The   skeleton owns the cold pulse + the fade-out side of the   reveal; the content owns the fade-in side. They share the   same duration / ease so the swap reads as one motion. */.t-skel { position: relative; }.t-skel-skeleton,.t-skel-content {  position: absolute;  inset: 0;}
.t-skel-skeleton {  z-index: 1;  opacity: 1;  filter: blur(0);  transition:    opacity var(--reveal-dur) var(--reveal-ease),    filter  var(--reveal-dur) var(--reveal-ease);}.t-skel-content {  z-index: 2;  opacity: 0;  filter: blur(var(--reveal-blur));  transition:    opacity var(--reveal-dur) var(--reveal-ease),    filter  var(--reveal-dur) var(--reveal-ease);}.t-skel.is-revealed .t-skel-skeleton {  opacity: 0;  filter: blur(var(--reveal-blur));}.t-skel.is-revealed .t-skel-content {  opacity: 1;  filter: blur(0);}/* Snap-back when replaying: kill transitions so the reverse   (revealed → skeleton) is instant. Drop `.is-resetting`   after a forced reflow and the next reveal animates again. */.t-skel.is-resetting .t-skel-skeleton,.t-skel.is-resetting .t-skel-content {  transition: none !important;}
/* Pulse: place the animation on the bar/avatar children, not   on the skeleton itself, so the skeleton's opacity / filter   stay free for the cross-fade transition above. */.t-skel-skeleton.is-pulsing > * {  animation: t-skel-pulse var(--pulse-dur) ease-in-out var(--pulse-count);}@keyframes t-skel-pulse {  0%, 100% { opacity: 1; }  50%      { opacity: var(--pulse-min); }}
@media (prefers-reduced-motion: reduce) {  .t-skel-skeleton, .t-skel-content {    transition: none !important;  }  .t-skel-skeleton.is-pulsing > * { animation: none !important; }}

The @media (prefers-reduced-motion: reduce) guard at the bottom of the snippet is required — keep it. It zeroes the transition for users who have asked for less motion at the OS level.

JavaScript orchestration

const skel = document.querySelector(".t-skel");const skeleton = skel.querySelector(".t-skel-skeleton");const cs = getComputedStyle(document.documentElement);const num = (name, fb) => {  const v = parseFloat(cs.getPropertyValue(name));  return Number.isFinite(v) ? v : fb;};
// Call when async data arrives:function reveal() {  skel.classList.add("is-revealed");}
// Demo replay: snap back, pulse, then reveal.function replay() {  skel.classList.add("is-resetting");  skel.classList.remove("is-revealed");  skeleton.classList.remove("is-pulsing");  void skeleton.offsetWidth;  skel.classList.remove("is-resetting");  skeleton.classList.add("is-pulsing");  const total = num("--pulse-dur", 1000) * num("--pulse-count", 1);  setTimeout(() => skel.classList.add("is-revealed"), total);}

Design engineering

Frameworks & libraries