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Keyframes

Compose multi-stage keyframes, interpolation, stepped motion, and fill behavior.

Preview

Live preview

Defined points in an animation (0%, 50%, 100%) that the browser fills the gaps between.

Preview
Keyframes
Authoritative vocabulary

Definition and close-term distinctions

English definitions are preserved verbatim from Animation Vocabulary; translations and distinctions help you choose precisely.

Canonical termkeyframes

Keyframes

关键帧
Authoritative definition

Defined points in an animation (0%, 50%, 100%) that the browser fills the gaps between.

Chinese translation

动画中预先定义的节点（如 0%、50%、100%），浏览器会补全节点之间的画面。

Browse all 91 terms
Design contract

Decide before this motion ships

Purpose, frequency, trigger, timing, interruptibility, and gesture rules shape the implementation.

Purpose

Define multi-stage states, interpolation behavior, stepped rhythm, and post-animation styles.

Frequency

Use for low-frequency motion with meaningful phases; simple feedback favors a single transition.

Trigger

Trigger from an explicit state change or replay action, with each keyframe representing a meaningful phase.

Enter / exit

Map the first frame to the pre-entry state and the last to the stable state; give exit its own shorter timeline.

Interruptibility

On interruption, build the next timeline from current computed styles instead of snapping to a keyframe.

Gesture and keyboard

The timeline itself needs no gesture; interactive progress controls support pointer, touch, and keyboard.

Reduced-motion strategy

Collapse to one state change and remove anticipation, overshoot, and repeated phases.

Output

Copy into your interface

Current parameters update visual-state CSS, semantic HTML, the required vanilla JS runtime, and an interaction prompt.

Updates with parameters
motion.css
.motion-demo.motion-demo--keyframes {
  position: relative;
  display: grid;
  place-items: center;
  width: min(100%, 34rem);
  min-height: 15rem;
  padding: 2rem;
  overflow: hidden;
  color: #18181b;
  background: #fafafa;
  border: 1px solid #e4e4e7;
  border-radius: 12px;
  isolation: isolate;
}

.motion-demo.motion-demo--keyframes *, .motion-demo.motion-demo--keyframes *::before, .motion-demo.motion-demo--keyframes *::after {
  box-sizing: border-box;
}

.motion-demo.motion-demo--keyframes .motion-surface {
  position: relative;
  display: grid;
  gap: 0.65rem;
  width: min(100%, 18rem);
  padding: 1.25rem;
  background: #ffffff;
  border: 1px solid #e4e4e7;
  border-radius: 8px;
  box-shadow: 0 1px 2px rgb(0 0 0 / 6%), 0 10px 28px rgb(0 0 0 / 7%);
}

.motion-demo.motion-demo--keyframes .motion-line {
  display: block;
  width: 100%;
  height: 0.5rem;
  background: #e4e4e7;
  border-radius: 999px;
}

.motion-demo.motion-demo--keyframes .motion-line:last-child { width: 62%; }

.motion-demo.motion-demo--keyframes .motion-button {
  position: relative;
  min-height: 2.75rem;
  padding: 0.75rem 1.1rem;
  color: white;
  font: inherit;
  font-weight: 700;
  background: #18181b;
  border: 0;
  border-radius: 7px;
  cursor: pointer;
}

.motion-demo.motion-demo--keyframes .motion-button:focus-visible { outline: 3px solid rgb(37 99 235 / 32%); outline-offset: 3px; }

.motion-demo.motion-demo--keyframes .motion-action-row {
  display: flex;
  justify-content: center;
  gap: 0.5rem;
  margin-top: 0.85rem;
}

.motion-demo.motion-demo--keyframes .motion-replay-scene {
  width: min(100%, 22rem);
  display: grid;
  place-items: center;
}

.motion-demo.motion-demo--keyframes .motion-pausable-scene {
  width: min(100%, 22rem);
  display: grid;
  place-items: center;
}

.motion-demo.motion-demo--keyframes button.motion-surface {
  color: inherit;
  font: inherit;
  text-align: start;
  cursor: pointer;
}

.motion-demo.motion-demo--keyframes .motion-replay-button,
.motion-demo.motion-demo--keyframes .motion-undo-button,
.motion-demo.motion-demo--keyframes .motion-dismiss-button,
.motion-demo.motion-demo--keyframes .motion-pause-button {
  min-height: 2.75rem;
  padding: 0.65rem 0.9rem;
  color: #18181b;
  font: 650 0.78rem/1 ui-sans-serif, system-ui, sans-serif;
  background: #ffffff;
  border: 1px solid #d4d4d8;
  border-radius: 7px;
  cursor: pointer;
}

.motion-demo.motion-demo--keyframes .motion-replay-button:focus-visible,
.motion-demo.motion-demo--keyframes .motion-undo-button:focus-visible,
.motion-demo.motion-demo--keyframes .motion-dismiss-button:focus-visible,
.motion-demo.motion-demo--keyframes .motion-pause-button:focus-visible,
.motion-demo.motion-demo--keyframes [data-reorder-item]:focus-visible,
.motion-demo.motion-demo--keyframes [data-swipe-target]:focus-visible {
  outline: 3px solid rgb(37 99 235 / 32%);
  outline-offset: 3px;
}

.motion-demo.motion-demo--keyframes .motion-status {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.motion-demo.motion-demo--keyframes .motion-ripple-ink {
  position: absolute;
  width: 12px;
  height: 12px;
  pointer-events: none;
  background: rgb(255 255 255 / 72%);
  border-radius: 50%;
  transform: translate(-50%, -50%) scale(0.95);
  opacity: 0;
}

.motion-demo.motion-demo--keyframes .motion-state-stack { position: relative; width: min(100%, 18rem); height: 9rem; }
.motion-demo.motion-demo--keyframes .motion-state { position: absolute; inset: 0; display: grid; place-items: center; padding: 1rem; background: #ffffff; border: 1px solid #e4e4e7; border-radius: 8px; }
.motion-demo.motion-demo--keyframes .motion-state--to { background: #18181b; color: white; }

.motion-demo.motion-demo--keyframes .motion-scroll-track > span { color: #71717a; font: 600 0.72rem/1.2 ui-monospace, monospace; letter-spacing: 0.08em; text-transform: uppercase; }
.motion-demo.motion-demo--keyframes .motion-orbit-item { display: grid; place-items: center; width: 2.5rem; height: 2.5rem; color: white; background: #2563eb; border-radius: 50%; }
.motion-demo.motion-demo--keyframes .motion-text-stack { position: relative; width: min(100%, 18rem); min-height: 4rem; }
.motion-demo.motion-demo--keyframes svg { width: min(100%, 20rem); height: auto; }

.motion-demo.motion-demo--keyframes .motion-surface { animation: motion-keyframes 720ms cubic-bezier(0.23, 1, 0.32, 1) 0ms 1 both; }
@keyframes motion-keyframes { 0% { opacity: 0.45; transform: translateX(-46px); } 50% { transform: translateX(46px) rotate(4deg); } 100% { opacity: 1; transform: translateX(46px); } }

@keyframes motion-keyframes-reduced-fade {
  from { opacity: 0.84; }
  to { opacity: 1; }
}

.force-reduced-motion .motion-demo.motion-demo--keyframes {
  animation: motion-keyframes-reduced-fade 160ms cubic-bezier(0.23, 1, 0.32, 1) both !important;
}

.force-reduced-motion .motion-demo.motion-demo--keyframes *,
.force-reduced-motion .motion-demo.motion-demo--keyframes *::before,
.force-reduced-motion .motion-demo.motion-demo--keyframes *::after {
  animation: none !important;
  animation-delay: 0ms !important;
  animation-iteration-count: 1 !important;
  transition-property: opacity, color, background-color, border-color !important;
  transition-duration: 160ms !important;
  transition-delay: 0ms !important;
  scroll-behavior: auto !important;
}

.force-reduced-motion .motion-demo.motion-demo--keyframes .motion-button,
.force-reduced-motion .motion-demo.motion-demo--keyframes [data-reorder-item],
.force-reduced-motion .motion-demo.motion-demo--keyframes [data-swipe-target],
.force-reduced-motion .motion-demo.motion-demo--keyframes [data-spring-target] {
  transform: none !important;
}

.force-reduced-motion .motion-demo.motion-demo--keyframes .motion-path { stroke-dashoffset: 0 !important; }
.force-reduced-motion .motion-demo.motion-demo--keyframes .motion-word--from { opacity: 0 !important; visibility: hidden; }
.force-reduced-motion .motion-demo.motion-demo--keyframes .motion-word:not(.motion-word--from) { opacity: 1 !important; filter: none !important; transform: none !important; }

@media (prefers-reduced-motion: reduce) {
  .motion-demo.motion-demo--keyframes {
    animation: motion-keyframes-reduced-fade 160ms cubic-bezier(0.23, 1, 0.32, 1) both !important;
  }

  .motion-demo.motion-demo--keyframes *, .motion-demo.motion-demo--keyframes *::before, .motion-demo.motion-demo--keyframes *::after {
    animation: none !important;
    animation-delay: 0ms !important;
    animation-iteration-count: 1 !important;
    transition-property: opacity, color, background-color, border-color !important;
    transition-duration: 160ms !important;
    transition-delay: 0ms !important;
    scroll-behavior: auto !important;
  }

  .motion-demo.motion-demo--keyframes .motion-button,
  .motion-demo.motion-demo--keyframes [data-reorder-item],
  .motion-demo.motion-demo--keyframes [data-swipe-target],
  .motion-demo.motion-demo--keyframes [data-spring-target] {
    transform: none !important;
  }

  .motion-demo.motion-demo--keyframes .motion-path { stroke-dashoffset: 0 !important; }
  .motion-demo.motion-demo--keyframes .motion-word--from { opacity: 0 !important; visibility: hidden; }
  .motion-demo.motion-demo--keyframes .motion-word:not(.motion-word--from) { opacity: 1 !important; filter: none !important; transform: none !important; }
}
Review notes

Pre-delivery review

  • Review whether every phase improves understanding.
  • Verify that fill-mode never leaves an unusable visual state.
Accessibility

Keep information accessible

Reduced motion

Collapse to one state change and remove anticipation, overshoot, and repeated phases.

Parameters

Parameter reference

ParameterRange / optionsDefaultPurpose
duration300ms–2400ms720msUses a longer demo duration so the full change stays observable; immediate production UI feedback should stay under 300ms.
modeKeyframes / Tween / StepsKeyframesSelects timeline mode.
steps2–124Adjusts steps.
fillNone / Forwards / BothBothSelects fill mode.
easeSoft / Snap / Calm / LinearSoftControls how velocity changes over time.
Related entries
StaggerDuration