---
title: Animation
subtitle: A guide to animating Base UI components.
description: A guide to animating Base UI components.
---

# Animation

A guide to animating Base UI components.

Base UI components can be animated using CSS transitions, CSS animations, or JavaScript animation libraries. Each component provides a number of data attributes to target its states, as well as a few attributes specifically for animation.

## CSS transitions

Use the following Base UI attributes for creating transitions when a component becomes visible or hidden:

- `[data-starting-style]` corresponds to the initial style to transition from.
- `[data-ending-style]` corresponds to the final style to transition to.

Transitions are recommended over CSS animations, because a transition can be smoothly cancelled midway.
For example, if the user closes a popup before it finishes opening, with CSS transitions it will smoothly animate to its closed state without any abrupt changes.

```css title="popover.css" {10-14}
.Popup {
  box-sizing: border-box;
  padding: 1rem 1.5rem;
  background-color: canvas;
  transform-origin: var(--transform-origin);
  transition:
    transform 150ms,
    opacity 150ms;

  &[data-starting-style],
  &[data-ending-style] {
    opacity: 0;
    transform: scale(0.9);
  }
}
```

## CSS animations

Use the following Base UI attributes for creating CSS animations when a component becomes visible or hidden:

- `[data-open]` corresponds to the style applied when a component becomes visible.
- `[data-closed]` corresponds to the style applied before a component becomes hidden.

```css title="popover.css"
@keyframes scaleIn {
  from {
    opacity: 0;
    transform: scale(0.9);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

@keyframes scaleOut {
  from {
    opacity: 1;
    transform: scale(1);
  }
  to {
    opacity: 0;
    transform: scale(0.9);
  }
}

.Popup[data-open] {
  animation: scaleIn 250ms ease-out;
}

.Popup[data-closed] {
  animation: scaleOut 250ms ease-in;
}
```

## JavaScript animations

JavaScript animation libraries such as [Motion](https://motion.dev) require control of the mounting and unmounting lifecycle of components in order for exit animations to play.

Base UI relies on [`element.getAnimations()`](https://developer.mozilla.org/en-US/docs/Web/API/Element/getAnimations) to detect if animations have finished on an element. When using Motion, `opacity` animations are reflected in `element.getAnimations()`, so Base UI automatically waits for the animation finish before unmounting the component. If `opacity` isn't part of your animation (such as in a translating drawer component), you should still animate it using a value close to `1` (such as `opacity: 0.9999`), so that Base UI can detect the animation.

### Animating components unmounted from DOM when closed with Motion

Most popup components like Popover, Dialog, Tooltip, and Menu are unmounted from the DOM when they are closed by default. To animate them with Motion:

- Make the component controlled with the `open` prop so `<AnimatePresence>` can see the state as a child
- Specify `keepMounted` on the `<Portal>` part
- Use the `render` prop to compose the `<Popup>` with `motion.div`

## Demo

### CSS Modules

This example shows how to implement the component using CSS Modules.

```css
/* index.module.css */
.Trigger {
  box-sizing: border-box;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 2.5rem;
  padding: 0 0.875rem;
  margin: 0;
  outline: 0;
  border: 1px solid var(--color-gray-200);
  border-radius: 0.375rem;
  background-color: var(--color-gray-50);
  font-family: inherit;
  font-size: 1rem;
  font-weight: 500;
  line-height: 1.5rem;
  color: var(--color-gray-900);
  user-select: none;

  @media (hover: hover) {
    &:hover {
      background-color: var(--color-gray-100);
    }
  }

  &:active {
    background-color: var(--color-gray-100);
  }

  &[data-popup-open] {
    background-color: var(--color-gray-100);
  }

  &:focus-visible {
    outline: 2px solid var(--color-blue);
    outline-offset: -1px;
  }
}

.Positioner {
  width: var(--positioner-width);
  height: var(--positioner-height);
  max-width: var(--available-width);
}

.Popup {
  box-sizing: border-box;
  padding: 1rem 1.5rem;
  border-radius: 0.5rem;
  background-color: canvas;
  color: var(--color-gray-900);
  transform-origin: var(--transform-origin);

  width: var(--popup-width, auto);
  height: var(--popup-height, auto);
  max-width: 500px;

  @media (prefers-color-scheme: light) {
    outline: 1px solid var(--color-gray-200);
    box-shadow:
      0 10px 15px -3px var(--color-gray-200),
      0 4px 6px -4px var(--color-gray-200);
  }

  @media (prefers-color-scheme: dark) {
    outline: 1px solid var(--color-gray-300);
    outline-offset: -1px;
  }
}
```

```tsx
/* index.tsx */
'use client';
import * as React from 'react';
import { Popover } from '@base-ui/react/popover';
import { AnimatePresence, motion } from 'motion/react';
import styles from './index.module.css';

export default function AnimatedPopoverMotionKeepMountedFalseDemo() {
  const [open, setOpen] = React.useState(false);

  return (
    <Popover.Root open={open} onOpenChange={setOpen}>
      <Popover.Trigger className={styles.Trigger}>Trigger</Popover.Trigger>
      <AnimatePresence>
        {open && (
          <Popover.Portal keepMounted>
            <Popover.Positioner className={styles.Positioner} sideOffset={8}>
              <Popover.Popup
                className={styles.Popup}
                render={
                  <motion.div
                    initial={{ opacity: 0, scale: 0.8 }}
                    animate={{ opacity: 1, scale: 1 }}
                    exit={{ opacity: 0, scale: 0.8 }}
                  />
                }
              >
                Popup
              </Popover.Popup>
            </Popover.Positioner>
          </Popover.Portal>
        )}
      </AnimatePresence>
    </Popover.Root>
  );
}
```

```jsx title="animated-popover.tsx" {12-18} "keepMounted"
function App() {
  const [open, setOpen] = React.useState(false);

  return (
    <Popover.Root open={open} onOpenChange={setOpen}>
      <Popover.Trigger>Trigger</Popover.Trigger>
      <AnimatePresence>
        {open && (
          <Popover.Portal keepMounted>
            <Popover.Positioner>
              <Popover.Popup
                render={
                  <motion.div
                    initial={{ opacity: 0, scale: 0.8 }}
                    animate={{ opacity: 1, scale: 1 }}
                    exit={{ opacity: 0, scale: 0.8 }}
                  />
                }
              >
                Popup
              </Popover.Popup>
            </Popover.Positioner>
          </Popover.Portal>
        )}
      </AnimatePresence>
    </Popover.Root>
  );
}
```

### Animating components kept in DOM when closed with Motion

Components that specify `keepMounted` remain rendered in the DOM when they are closed. These elements need a different approach to be animated with Motion:

- Use the `render` prop to compose the `<Popup>` with `motion.div`
- Animate the properties based on the `open` state, avoiding `<AnimatePresence>`

## Demo

### CSS Modules

This example shows how to implement the component using CSS Modules.

```css
/* index.module.css */
.Trigger {
  box-sizing: border-box;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 2.5rem;
  padding: 0 0.875rem;
  margin: 0;
  outline: 0;
  border: 1px solid var(--color-gray-200);
  border-radius: 0.375rem;
  background-color: var(--color-gray-50);
  font-family: inherit;
  font-size: 1rem;
  font-weight: 500;
  line-height: 1.5rem;
  color: var(--color-gray-900);
  user-select: none;

  @media (hover: hover) {
    &:hover {
      background-color: var(--color-gray-100);
    }
  }

  &:active {
    background-color: var(--color-gray-100);
  }

  &[data-popup-open] {
    background-color: var(--color-gray-100);
  }

  &:focus-visible {
    outline: 2px solid var(--color-blue);
    outline-offset: -1px;
  }
}

.Positioner {
  width: var(--positioner-width);
  height: var(--positioner-height);
  max-width: var(--available-width);
}

.Popup {
  box-sizing: border-box;
  padding: 1rem 1.5rem;
  border-radius: 0.5rem;
  background-color: canvas;
  color: var(--color-gray-900);
  transform-origin: var(--transform-origin);

  width: var(--popup-width, auto);
  height: var(--popup-height, auto);
  max-width: 500px;

  @media (prefers-color-scheme: light) {
    outline: 1px solid var(--color-gray-200);
    box-shadow:
      0 10px 15px -3px var(--color-gray-200),
      0 4px 6px -4px var(--color-gray-200);
  }

  @media (prefers-color-scheme: dark) {
    outline: 1px solid var(--color-gray-300);
    outline-offset: -1px;
  }
}
```

```tsx
/* index.tsx */
'use client';
import * as React from 'react';
import { Popover } from '@base-ui/react/popover';
import { motion, type HTMLMotionProps } from 'motion/react';
import styles from './index.module.css';

export default function AnimatedPopoverMotionKeepMountedTrueDemo() {
  return (
    <Popover.Root>
      <Popover.Trigger className={styles.Trigger}>Trigger</Popover.Trigger>
      <Popover.Portal keepMounted>
        <Popover.Positioner className={styles.Positioner} sideOffset={8}>
          <Popover.Popup
            className={styles.Popup}
            render={(props, state) => (
              <motion.div
                {...(props as HTMLMotionProps<'div'>)}
                initial={false}
                animate={{
                  opacity: state.open ? 1 : 0,
                  scale: state.open ? 1 : 0.8,
                }}
              />
            )}
          >
            Popup
          </Popover.Popup>
        </Popover.Positioner>
      </Popover.Portal>
    </Popover.Root>
  );
}
```

```jsx title="animated-popover.tsx" {8-17} "keepMounted"
function App() {
  return (
    <Popover.Root>
      <Popover.Trigger>Trigger</Popover.Trigger>
      <Popover.Portal keepMounted>
        <Popover.Positioner>
          <Popover.Popup
            render={(props, state) => (
              <motion.div
                {...(props as HTMLMotionProps<'div'>)}
                initial={false}
                animate={{
                  opacity: state.open ? 1 : 0,
                  scale: state.open ? 1 : 0.8,
                }}
              />
            )}
          >
            Popup
          </Popover.Popup>
        </Popover.Positioner>
      </Popover.Portal>
    </Popover.Root>
  );
}
```

### Animating Select component with Motion

The Select component is initially unmounted but remains mounted after interaction. To animate it with Motion, a mix of the two previous approaches is needed.

## Demo

### CSS Modules

This example shows how to implement the component using CSS Modules.

```css
/* index.module.css */
.Select {
  box-sizing: border-box;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  height: 2.5rem;
  padding-left: 0.875rem;
  padding-right: 0.75rem;
  margin: 0;
  outline: 0;
  border: 1px solid var(--color-gray-200);
  border-radius: 0.375rem;
  background-color: canvas;
  font-family: inherit;
  font-size: 1rem;
  line-height: 1.5rem;
  color: var(--color-gray-900);
  -webkit-user-select: none;
  user-select: none;
  min-width: 9rem;

  @media (hover: hover) {
    &:hover {
      background-color: var(--color-gray-100);
    }
  }

  &[data-popup-open] {
    background-color: var(--color-gray-100);
  }

  &:focus-visible {
    outline: 2px solid var(--color-blue);
    outline-offset: -1px;
  }
}

.SelectIcon {
  display: flex;
}

.Positioner {
  outline: none;
  z-index: 1;
  -webkit-user-select: none;
  user-select: none;
}

.Popup {
  box-sizing: border-box;
  border-radius: 0.375rem;
  background-color: canvas;
  background-clip: padding-box;
  color: var(--color-gray-900);
  min-width: var(--anchor-width);
  transform-origin: var(--transform-origin);

  &[data-side='none'] {
    min-width: calc(var(--anchor-width) + 1rem);
  }

  @media (prefers-color-scheme: light) {
    outline: 1px solid var(--color-gray-200);
    box-shadow:
      0 10px 15px -3px var(--color-gray-200),
      0 4px 6px -4px var(--color-gray-200);
  }

  @media (prefers-color-scheme: dark) {
    outline: 1px solid var(--color-gray-300);
  }
}

.List {
  box-sizing: border-box;
  position: relative;
  padding-block: 0.25rem;
  overflow-y: auto;
  max-height: var(--available-height);
  scroll-padding-block: 1.5rem;
}

.Arrow {
  display: flex;

  &[data-side='top'] {
    bottom: -8px;
    rotate: 180deg;
  }

  &[data-side='bottom'] {
    top: -8px;
    rotate: 0deg;
  }

  &[data-side='left'] {
    right: -13px;
    rotate: 90deg;
  }

  &[data-side='right'] {
    left: -13px;
    rotate: -90deg;
  }
}

.ArrowFill {
  fill: canvas;
}

.ArrowOuterStroke {
  @media (prefers-color-scheme: light) {
    fill: var(--color-gray-200);
  }
}

.ArrowInnerStroke {
  @media (prefers-color-scheme: dark) {
    fill: var(--color-gray-300);
  }
}

.Item {
  box-sizing: border-box;
  outline: 0;
  font-size: 0.875rem;
  line-height: 1rem;
  padding-block: 0.5rem;
  padding-left: 0.625rem;
  padding-right: 1rem;
  display: grid;
  gap: 0.5rem;
  align-items: center;
  grid-template-columns: 0.75rem 1fr;
  cursor: default;
  -webkit-user-select: none;
  user-select: none;

  @media (pointer: coarse) {
    padding-block: 0.625rem;
    font-size: 0.925rem;
  }

  [data-side='none'] & {
    font-size: 1rem;
    padding-right: 3rem;
  }

  &[data-highlighted] {
    z-index: 0;
    position: relative;
    color: var(--color-gray-50);
  }

  &[data-highlighted]::before {
    content: '';
    z-index: -1;
    position: absolute;
    inset-block: 0;
    inset-inline: 0.25rem;
    border-radius: 0.25rem;
    background-color: var(--color-gray-900);
  }
}

.ItemIndicator {
  grid-column-start: 1;
}

.ItemIndicatorIcon {
  display: block;
  width: 0.75rem;
  height: 0.75rem;
}

.ItemText {
  grid-column-start: 2;
}

.ScrollArrow {
  width: 100%;
  background: canvas;
  z-index: 1;
  text-align: center;
  cursor: default;
  border-radius: 0.375rem;
  height: 1rem;
  font-size: 0.75rem;
  display: flex;
  align-items: center;
  justify-content: center;

  &::before {
    content: '';
    position: absolute;
    width: 100%;
    height: 100%;
    left: 0;
  }

  &[data-direction='up'] {
    &[data-side='none'] {
      &::before {
        top: -100%;
      }
    }
  }

  &[data-direction='down'] {
    bottom: 0;

    &[data-side='none'] {
      &::before {
        bottom: -100%;
      }
    }
  }
}
```

```tsx
/* index.tsx */
'use client';
import * as React from 'react';
import { Select } from '@base-ui/react/select';
import { AnimatePresence, motion } from 'motion/react';
import styles from './index.module.css';

const fonts = [
  { label: 'Select font', value: null },
  { label: 'Sans-serif', value: 'sans' },
  { label: 'Serif', value: 'serif' },
  { label: 'Monospace', value: 'mono' },
  { label: 'Cursive', value: 'cursive' },
];

export default function AnimatedSelectMotionDemo() {
  const [open, setOpen] = React.useState(false);
  const [mounted, setMounted] = React.useState(false);

  const positionerRef = React.useCallback(() => {
    setMounted(true);
  }, []);

  const portalMounted = open || mounted;

  // Once the trigger has been interacted with, the popup will always be
  // mounted in the DOM. We can use this to determine which animation variant
  // to use: if it's already mounted, we switch to use "keepMounted" animations.
  const motionElement = mounted ? (
    <motion.div
      initial={false}
      animate={{
        opacity: open ? 1 : 0,
        scale: open ? 1 : 0.8,
      }}
    />
  ) : (
    <motion.div
      initial={{ opacity: 0, scale: 0.8 }}
      animate={{ opacity: 1, scale: 1 }}
      exit={{ opacity: 0, scale: 0.8 }}
    />
  );

  return (
    <Select.Root items={fonts} open={open} onOpenChange={setOpen}>
      <Select.Trigger className={styles.Select}>
        <Select.Value />
        <Select.Icon className={styles.SelectIcon}>
          <ChevronUpDownIcon />
        </Select.Icon>
      </Select.Trigger>
      <AnimatePresence>
        {portalMounted && (
          <Select.Portal>
            <Select.Positioner className={styles.Positioner} sideOffset={8} ref={positionerRef}>
              <Select.Popup className={styles.Popup} render={motionElement}>
                <Select.ScrollUpArrow className={styles.ScrollArrow} />
                <Select.List className={styles.List}>
                  {fonts.map(({ label, value }) => (
                    <Select.Item key={label} value={value} className={styles.Item}>
                      <Select.ItemIndicator className={styles.ItemIndicator}>
                        <CheckIcon className={styles.ItemIndicatorIcon} />
                      </Select.ItemIndicator>
                      <Select.ItemText className={styles.ItemText}>{label}</Select.ItemText>
                    </Select.Item>
                  ))}
                </Select.List>
                <Select.ScrollDownArrow className={styles.ScrollArrow} />
              </Select.Popup>
            </Select.Positioner>
          </Select.Portal>
        )}
      </AnimatePresence>
    </Select.Root>
  );
}

function ChevronUpDownIcon(props: React.ComponentProps<'svg'>) {
  return (
    <svg
      width="8"
      height="12"
      viewBox="0 0 8 12"
      fill="none"
      stroke="currentcolor"
      strokeWidth="1.5"
      {...props}
    >
      <path d="M0.5 4.5L4 1.5L7.5 4.5" />
      <path d="M0.5 7.5L4 10.5L7.5 7.5" />
    </svg>
  );
}

function CheckIcon(props: React.ComponentProps<'svg'>) {
  return (
    <svg fill="currentcolor" width="10" height="10" viewBox="0 0 10 10" {...props}>
      <path d="M9.1603 1.12218C9.50684 1.34873 9.60427 1.81354 9.37792 2.16038L5.13603 8.66012C5.01614 8.8438 4.82192 8.96576 4.60451 8.99384C4.3871 9.02194 4.1683 8.95335 4.00574 8.80615L1.24664 6.30769C0.939709 6.02975 0.916013 5.55541 1.19372 5.24822C1.47142 4.94102 1.94536 4.91731 2.2523 5.19524L4.36085 7.10461L8.12299 1.33999C8.34934 0.993152 8.81376 0.895638 9.1603 1.12218Z" />
    </svg>
  );
}
```

### Manual unmounting

For full control, you can manually unmount the component when it's closed once animations have finished using an `actionsRef` passed to the `<Root>`:

```jsx title="manual-unmount.tsx" "actionsRef"
function App() {
  const [open, setOpen] = React.useState(false);
  const actionsRef = React.useRef(null);

  return (
    <Popover.Root open={open} onOpenChange={setOpen} actionsRef={actionsRef}>
      <Popover.Trigger>Trigger</Popover.Trigger>
      <AnimatePresence>
        {open && (
          <Popover.Portal keepMounted>
            <Popover.Positioner>
              <Popover.Popup
                render={
                  <motion.div
                    initial={{ scale: 0 }}
                    animate={{ scale: 1 }}
                    exit={{ scale: 0 }}
                    onAnimationComplete={() => {
                      if (!open) {
                        actionsRef.current.unmount();
                      }
                    }}
                  />
                }
              >
                Popup
              </Popover.Popup>
            </Popover.Positioner>
          </Popover.Portal>
        )}
      </AnimatePresence>
    </Popover.Root>
  );
}
```