# Page Indicator

A row of dots that shows the current page in a pager or carousel, with an elongated dot for the active page.

Page Indicator is an open-source mobile component from suiss/uim for React Native and Expo, with SwiftUI and Jetpack Compose versions built from the same design tokens. The @esuiss/uim CLI copies its source into your project, so you own the code.

Source: https://uim.suiss.app/docs/components/page-indicator

![Preview](https://uim.suiss.app/previews/components-page-indicator--default.light.webp)

```tsx
import { PageIndicator } from "@/components/ui/page-indicator"

export function PageIndicatorExample() {
  return (
    <PageIndicator count={5} index={1} />
  )
}
```

```swift
import EsuissUI
import SwiftUI

struct PageIndicatorExample: View {
  var body: some View {
    PageIndicator(count: 5, index: 1)
  }
}
```

```kotlin
import androidx.compose.runtime.Composable
import com.esuiss.ui.components.PageIndicator

@Composable
fun PageIndicatorExample() {
    PageIndicator(count = 5, index = 1)
}
```

`PageIndicator` draws one dot per page and widens the active one into a pill. Width and position changes animate with Reanimated. When `count` exceeds `maxVisible`, only a window of dots is shown; the window slides to keep the active dot near the center and the dots at its edges shrink to hint that more pages exist.

It comes in two sizes, `default` and `sm`, and two variants: `default` uses the label color for the active dot and `accent` uses the accent color.

## Installation

```bash title="Terminal"
npx @esuiss/uim@latest add page-indicator
```

```bash title="Terminal"
npx @esuiss/uim@latest add page-indicator --platform swift
```

```bash title="Terminal"
npx @esuiss/uim@latest add page-indicator --platform kotlin
```

### Manual

**Uniwind**

1. Install the dependencies:

```bash title="Terminal"
npx expo install cn react-native-reanimated react-native-worklets
```

2. Add the pieces it builds on: the primitives `components/primitives/haptics.tsx`.

3. Copy the source into `components/ui/page-indicator.tsx`:

```tsx title="uniwind/components/ui/page-indicator.tsx"
import { cn } from "cn"
import * as React from "react"
import {
  type AccessibilityActionEvent,
  Pressable,
  View,
  type ViewProps,
} from "react-native"
import {
  Easing,
  ReduceMotion,
  useAnimatedStyle,
  useSharedValue,
  withTiming,
} from "react-native-reanimated"
import { useHaptics } from "@/components/primitives/haptics"
import { AnimatedView } from "@/components/ui/animated-view"

type PageIndicatorSize = "default" | "sm"

type PageIndicatorVariant = "default" | "accent"

const SIZES: Record<
  PageIndicatorSize,
  { dot: number; active: number; gap: number }
> = {
  default: { dot: 8, active: 20, gap: 8 },
  sm: { dot: 6, active: 14, gap: 6 },
}

const TIMING = {
  duration: 300,
  easing: Easing.bezier(0.32, 0.72, 0, 1),
  reduceMotion: ReduceMotion.System,
}

const ACTIONS = [{ name: "increment" }, { name: "decrement" }]

function windowStart(count: number, index: number, maxVisible: number) {
  if (count <= maxVisible) return 0
  return Math.min(
    Math.max(index - Math.floor(maxVisible / 2), 0),
    count - maxVisible
  )
}

function dotScale(
  position: number,
  start: number,
  count: number,
  maxVisible: number
) {
  if (count <= maxVisible) return 1
  const offset = position - start
  if (offset < 0 || offset >= maxVisible) return 0
  const end = start + maxVisible < count
  if (start > 0 && offset === 0) return 0.5
  if (start > 0 && offset === 1) return 0.75
  if (end && offset === maxVisible - 1) return 0.5
  if (end && offset === maxVisible - 2) return 0.75
  return 1
}

function PageIndicatorDot({
  active,
  scale,
  size,
  variant,
  onPress,
}: {
  active: boolean
  scale: number
  size: PageIndicatorSize
  variant: PageIndicatorVariant
  onPress?: () => void
}) {
  const metrics = SIZES[size]
  const width = useSharedValue(active ? metrics.active : metrics.dot)
  const dotScaleValue = useSharedValue(scale)

  React.useEffect(() => {
    width.value = withTiming(active ? metrics.active : metrics.dot, TIMING)
  }, [active, metrics, width])

  React.useEffect(() => {
    dotScaleValue.value = withTiming(scale, TIMING)
  }, [scale, dotScaleValue])

  const animatedStyle = useAnimatedStyle(() => ({
    width: width.value,
    transform: [{ scale: dotScaleValue.value }],
  }))

  return (
    <Pressable
      accessible={false}
      disabled={!onPress}
      onPress={onPress}
      hitSlop={{
        top: 8,
        bottom: 8,
        left: metrics.gap / 2,
        right: metrics.gap / 2,
      }}
    >
      <AnimatedView
        className={cn(
          "rounded-full",
          active
            ? variant === "accent"
              ? "bg-accent"
              : "bg-label"
            : "bg-label-quaternary"
        )}
        style={[{ height: metrics.dot }, animatedStyle]}
      />
    </Pressable>
  )
}

function PageIndicator({
  count,
  index,
  onIndexChange,
  size = "default",
  variant = "default",
  maxVisible = 7,
  accessibilityLabel = "Page",
  className,
  ...props
}: Omit<ViewProps, "children"> & {
  count: number
  index: number
  onIndexChange?: (index: number) => void
  size?: PageIndicatorSize
  variant?: PageIndicatorVariant
  maxVisible?: number
}) {
  const haptics = useHaptics()
  const metrics = SIZES[size]
  const visible = Math.max(3, maxVisible)
  const current = Math.min(Math.max(index, 0), Math.max(0, count - 1))
  const start = windowStart(count, current, visible)
  const shown = Math.min(count, visible)
  const frameWidth =
    shown * metrics.dot +
    (shown - 1) * metrics.gap +
    metrics.active -
    metrics.dot
  const offset = useSharedValue(-start * (metrics.dot + metrics.gap))

  React.useEffect(() => {
    offset.value = withTiming(-start * (metrics.dot + metrics.gap), TIMING)
  }, [start, metrics, offset])

  const rowStyle = useAnimatedStyle(() => ({
    transform: [{ translateX: offset.value }],
  }))

  if (count <= 0) return null

  const select = (next: number) => {
    if (!onIndexChange || next === current) return
    haptics.selection()
    onIndexChange(next)
  }

  const onAccessibilityAction = (event: AccessibilityActionEvent) => {
    if (!onIndexChange) return
    const step =
      event.nativeEvent.actionName === "increment"
        ? 1
        : event.nativeEvent.actionName === "decrement"
          ? -1
          : 0
    const next = Math.min(Math.max(current + step, 0), count - 1)
    if (next !== current) onIndexChange(next)
  }

  return (
    <View
      accessible
      accessibilityRole="adjustable"
      accessibilityLabel={accessibilityLabel}
      accessibilityValue={{ text: `${current + 1} of ${count}` }}
      accessibilityActions={onIndexChange ? ACTIONS : undefined}
      onAccessibilityAction={onAccessibilityAction}
      className={cn("items-center justify-center self-center", className)}
      {...props}
    >
      <View
        className="justify-center overflow-hidden"
        style={{ width: frameWidth, height: metrics.dot + 16 }}
      >
        <AnimatedView
          className="flex-row items-center"
          style={[{ gap: metrics.gap }, rowStyle]}
        >
          {Array.from({ length: count }, (_, position) => position).map(
            (position) => (
              <PageIndicatorDot
                key={position}
                active={position === current}
                scale={dotScale(position, start, count, visible)}
                size={size}
                variant={variant}
                onPress={onIndexChange ? () => select(position) : undefined}
              />
            )
          )}
        </AnimatedView>
      </View>
    </View>
  )
}

export type { PageIndicatorSize, PageIndicatorVariant }
export { PageIndicator }
```

4. Update the import paths to match your project.

**NativeWind**

1. Install the dependencies:

```bash title="Terminal"
npx expo install cn react-native-reanimated react-native-worklets
```

2. Add the pieces it builds on: the primitives `components/primitives/haptics.tsx`.

3. Copy the source into `components/ui/page-indicator.tsx`:

```tsx title="nativewind/components/ui/page-indicator.tsx"
import { cn } from "cn"
import * as React from "react"
import {
  type AccessibilityActionEvent,
  Pressable,
  View,
  type ViewProps,
} from "react-native"
import {
  Easing,
  ReduceMotion,
  useAnimatedStyle,
  useSharedValue,
  withTiming,
} from "react-native-reanimated"
import { useHaptics } from "@/components/primitives/haptics"
import { AnimatedView } from "@/components/ui/animated-view"

type PageIndicatorSize = "default" | "sm"

type PageIndicatorVariant = "default" | "accent"

const SIZES: Record<
  PageIndicatorSize,
  { dot: number; active: number; gap: number }
> = {
  default: { dot: 8, active: 20, gap: 8 },
  sm: { dot: 6, active: 14, gap: 6 },
}

const TIMING = {
  duration: 300,
  easing: Easing.bezier(0.32, 0.72, 0, 1),
  reduceMotion: ReduceMotion.System,
}

const ACTIONS = [{ name: "increment" }, { name: "decrement" }]

function windowStart(count: number, index: number, maxVisible: number) {
  if (count <= maxVisible) return 0
  return Math.min(
    Math.max(index - Math.floor(maxVisible / 2), 0),
    count - maxVisible
  )
}

function dotScale(
  position: number,
  start: number,
  count: number,
  maxVisible: number
) {
  if (count <= maxVisible) return 1
  const offset = position - start
  if (offset < 0 || offset >= maxVisible) return 0
  const end = start + maxVisible < count
  if (start > 0 && offset === 0) return 0.5
  if (start > 0 && offset === 1) return 0.75
  if (end && offset === maxVisible - 1) return 0.5
  if (end && offset === maxVisible - 2) return 0.75
  return 1
}

function PageIndicatorDot({
  active,
  scale,
  size,
  variant,
  onPress,
}: {
  active: boolean
  scale: number
  size: PageIndicatorSize
  variant: PageIndicatorVariant
  onPress?: () => void
}) {
  const metrics = SIZES[size]
  const width = useSharedValue(active ? metrics.active : metrics.dot)
  const dotScaleValue = useSharedValue(scale)

  React.useEffect(() => {
    width.value = withTiming(active ? metrics.active : metrics.dot, TIMING)
  }, [active, metrics, width])

  React.useEffect(() => {
    dotScaleValue.value = withTiming(scale, TIMING)
  }, [scale, dotScaleValue])

  const animatedStyle = useAnimatedStyle(() => ({
    width: width.value,
    transform: [{ scale: dotScaleValue.value }],
  }))

  return (
    <Pressable
      accessible={false}
      disabled={!onPress}
      onPress={onPress}
      hitSlop={{
        top: 8,
        bottom: 8,
        left: metrics.gap / 2,
        right: metrics.gap / 2,
      }}
    >
      <AnimatedView
        className={cn(
          "rounded-full",
          active
            ? variant === "accent"
              ? "bg-accent"
              : "bg-label"
            : "bg-label-quaternary"
        )}
        style={[{ height: metrics.dot }, animatedStyle]}
      />
    </Pressable>
  )
}

function PageIndicator({
  count,
  index,
  onIndexChange,
  size = "default",
  variant = "default",
  maxVisible = 7,
  accessibilityLabel = "Page",
  className,
  ...props
}: Omit<ViewProps, "children"> & {
  count: number
  index: number
  onIndexChange?: (index: number) => void
  size?: PageIndicatorSize
  variant?: PageIndicatorVariant
  maxVisible?: number
}) {
  const haptics = useHaptics()
  const metrics = SIZES[size]
  const visible = Math.max(3, maxVisible)
  const current = Math.min(Math.max(index, 0), Math.max(0, count - 1))
  const start = windowStart(count, current, visible)
  const shown = Math.min(count, visible)
  const frameWidth =
    shown * metrics.dot +
    (shown - 1) * metrics.gap +
    metrics.active -
    metrics.dot
  const offset = useSharedValue(-start * (metrics.dot + metrics.gap))

  React.useEffect(() => {
    offset.value = withTiming(-start * (metrics.dot + metrics.gap), TIMING)
  }, [start, metrics, offset])

  const rowStyle = useAnimatedStyle(() => ({
    transform: [{ translateX: offset.value }],
  }))

  if (count <= 0) return null

  const select = (next: number) => {
    if (!onIndexChange || next === current) return
    haptics.selection()
    onIndexChange(next)
  }

  const onAccessibilityAction = (event: AccessibilityActionEvent) => {
    if (!onIndexChange) return
    const step =
      event.nativeEvent.actionName === "increment"
        ? 1
        : event.nativeEvent.actionName === "decrement"
          ? -1
          : 0
    const next = Math.min(Math.max(current + step, 0), count - 1)
    if (next !== current) onIndexChange(next)
  }

  return (
    <View
      accessible
      accessibilityRole="adjustable"
      accessibilityLabel={accessibilityLabel}
      accessibilityValue={{ text: `${current + 1} of ${count}` }}
      accessibilityActions={onIndexChange ? ACTIONS : undefined}
      onAccessibilityAction={onAccessibilityAction}
      className={cn("items-center justify-center self-center", className)}
      {...props}
    >
      <View
        className="justify-center overflow-hidden"
        style={{ width: frameWidth, height: metrics.dot + 16 }}
      >
        <AnimatedView
          className="flex-row items-center"
          style={[{ gap: metrics.gap }, rowStyle]}
        >
          {Array.from({ length: count }, (_, position) => position).map(
            (position) => (
              <PageIndicatorDot
                key={position}
                active={position === current}
                scale={dotScale(position, start, count, visible)}
                size={size}
                variant={variant}
                onPress={onIndexChange ? () => select(position) : undefined}
              />
            )
          )}
        </AnimatedView>
      </View>
    </View>
  )
}

export type { PageIndicatorSize, PageIndicatorVariant }
export { PageIndicator }
```

4. Update the import paths to match your project.

**StyleSheet**

1. Install the dependencies:

```bash title="Terminal"
npx expo install react-native-reanimated react-native-worklets
```

2. Add the pieces it builds on: the primitives `components/primitives/haptics.tsx`.

3. Copy the source into `components/ui/page-indicator.tsx`:

```tsx title="stylesheet/components/ui/page-indicator.tsx"
import * as React from "react"
import {
  type AccessibilityActionEvent,
  Pressable,
  StyleSheet,
  View,
  type ViewProps,
} from "react-native"
import {
  Easing,
  ReduceMotion,
  useAnimatedStyle,
  useSharedValue,
  withTiming,
} from "react-native-reanimated"
import { useHaptics } from "@/components/primitives/haptics"
import { AnimatedView } from "@/components/ui/animated-view"
import { radius, useTheme } from "@/components/ui/theme"

type PageIndicatorSize = "default" | "sm"

type PageIndicatorVariant = "default" | "accent"

const SIZES: Record<
  PageIndicatorSize,
  { dot: number; active: number; gap: number }
> = {
  default: { dot: 8, active: 20, gap: 8 },
  sm: { dot: 6, active: 14, gap: 6 },
}

const TIMING = {
  duration: 300,
  easing: Easing.bezier(0.32, 0.72, 0, 1),
  reduceMotion: ReduceMotion.System,
}

const styles = StyleSheet.create({
  root: { alignItems: "center", justifyContent: "center", alignSelf: "center" },
  frame: { justifyContent: "center", overflow: "hidden" },
  row: { flexDirection: "row", alignItems: "center" },
  dot: { borderRadius: radius.full },
})

const ACTIONS = [{ name: "increment" }, { name: "decrement" }]

function windowStart(count: number, index: number, maxVisible: number) {
  if (count <= maxVisible) return 0
  return Math.min(
    Math.max(index - Math.floor(maxVisible / 2), 0),
    count - maxVisible
  )
}

function dotScale(
  position: number,
  start: number,
  count: number,
  maxVisible: number
) {
  if (count <= maxVisible) return 1
  const offset = position - start
  if (offset < 0 || offset >= maxVisible) return 0
  const end = start + maxVisible < count
  if (start > 0 && offset === 0) return 0.5
  if (start > 0 && offset === 1) return 0.75
  if (end && offset === maxVisible - 1) return 0.5
  if (end && offset === maxVisible - 2) return 0.75
  return 1
}

function PageIndicatorDot({
  active,
  scale,
  size,
  variant,
  onPress,
}: {
  active: boolean
  scale: number
  size: PageIndicatorSize
  variant: PageIndicatorVariant
  onPress?: () => void
}) {
  const { colors } = useTheme()
  const metrics = SIZES[size]
  const width = useSharedValue(active ? metrics.active : metrics.dot)
  const dotScaleValue = useSharedValue(scale)

  React.useEffect(() => {
    width.value = withTiming(active ? metrics.active : metrics.dot, TIMING)
  }, [active, metrics, width])

  React.useEffect(() => {
    dotScaleValue.value = withTiming(scale, TIMING)
  }, [scale, dotScaleValue])

  const animatedStyle = useAnimatedStyle(() => ({
    width: width.value,
    transform: [{ scale: dotScaleValue.value }],
  }))

  return (
    <Pressable
      accessible={false}
      disabled={!onPress}
      onPress={onPress}
      hitSlop={{
        top: 8,
        bottom: 8,
        left: metrics.gap / 2,
        right: metrics.gap / 2,
      }}
    >
      <AnimatedView
        style={[
          styles.dot,
          {
            height: metrics.dot,
            backgroundColor: active
              ? variant === "accent"
                ? colors.accent
                : colors.label
              : colors.labelQuaternary,
          },
          animatedStyle,
        ]}
      />
    </Pressable>
  )
}

function PageIndicator({
  count,
  index,
  onIndexChange,
  size = "default",
  variant = "default",
  maxVisible = 7,
  accessibilityLabel = "Page",
  style,
  ...props
}: Omit<ViewProps, "children"> & {
  count: number
  index: number
  onIndexChange?: (index: number) => void
  size?: PageIndicatorSize
  variant?: PageIndicatorVariant
  maxVisible?: number
}) {
  const haptics = useHaptics()
  const metrics = SIZES[size]
  const visible = Math.max(3, maxVisible)
  const current = Math.min(Math.max(index, 0), Math.max(0, count - 1))
  const start = windowStart(count, current, visible)
  const shown = Math.min(count, visible)
  const frameWidth =
    shown * metrics.dot +
    (shown - 1) * metrics.gap +
    metrics.active -
    metrics.dot
  const offset = useSharedValue(-start * (metrics.dot + metrics.gap))

  React.useEffect(() => {
    offset.value = withTiming(-start * (metrics.dot + metrics.gap), TIMING)
  }, [start, metrics, offset])

  const rowStyle = useAnimatedStyle(() => ({
    transform: [{ translateX: offset.value }],
  }))

  if (count <= 0) return null

  const select = (next: number) => {
    if (!onIndexChange || next === current) return
    haptics.selection()
    onIndexChange(next)
  }

  const onAccessibilityAction = (event: AccessibilityActionEvent) => {
    if (!onIndexChange) return
    const step =
      event.nativeEvent.actionName === "increment"
        ? 1
        : event.nativeEvent.actionName === "decrement"
          ? -1
          : 0
    const next = Math.min(Math.max(current + step, 0), count - 1)
    if (next !== current) onIndexChange(next)
  }

  return (
    <View
      accessible
      accessibilityRole="adjustable"
      accessibilityLabel={accessibilityLabel}
      accessibilityValue={{ text: `${current + 1} of ${count}` }}
      accessibilityActions={onIndexChange ? ACTIONS : undefined}
      onAccessibilityAction={onAccessibilityAction}
      style={[styles.root, style]}
      {...props}
    >
      <View
        style={[styles.frame, { width: frameWidth, height: metrics.dot + 16 }]}
      >
        <AnimatedView style={[styles.row, { gap: metrics.gap }, rowStyle]}>
          {Array.from({ length: count }, (_, position) => position).map(
            (position) => (
              <PageIndicatorDot
                key={position}
                active={position === current}
                scale={dotScale(position, start, count, visible)}
                size={size}
                variant={variant}
                onPress={onIndexChange ? () => select(position) : undefined}
              />
            )
          )}
        </AnimatedView>
      </View>
    </View>
  )
}

export type { PageIndicatorSize, PageIndicatorVariant }
export { PageIndicator }
```

4. Update the import paths to match your project.

**SwiftUI**

1. Target iOS 17 or later.

2. Add the Swift package to your app:

```swift title="Package.swift"
.package(url: "https://github.com/phosphor-icons/swift", from: "2.1.0")
```

3. Copy the theme files every view uses:

```swift title="swift/Theme/Theme.swift"
import SwiftUI
import UIKit

struct RGBA: Sendable {
  let red: CGFloat
  let green: CGFloat
  let blue: CGFloat
  let alpha: CGFloat

  init(_ hex: UInt32, _ alpha: CGFloat = 1) {
    red = CGFloat((hex >> 16) & 0xFF) / 255
    green = CGFloat((hex >> 8) & 0xFF) / 255
    blue = CGFloat(hex & 0xFF) / 255
    self.alpha = alpha
  }

  var uiColor: UIColor {
    UIColor(red: red, green: green, blue: blue, alpha: alpha)
  }
}

extension Color {
  static func adaptive(light: RGBA, dark: RGBA) -> Color {
    let lightColor = light.uiColor
    let darkColor = dark.uiColor
    return Color(uiColor: UIColor { traits in
      traits.userInterfaceStyle == .dark ? darkColor : lightColor
    })
  }
}

public struct TextStyle: Sendable, Hashable {
  public let size: CGFloat
  public let lineHeight: CGFloat
  public let letterSpacing: CGFloat

  public init(size: CGFloat, lineHeight: CGFloat, letterSpacing: CGFloat) {
    self.size = size
    self.lineHeight = lineHeight
    self.letterSpacing = letterSpacing
  }

  public func font(weight: Font.Weight = .regular) -> Font {
    .system(size: size, weight: weight)
  }

  public var lineSpacing: CGFloat {
    max(0, lineHeight - UIFont.systemFont(ofSize: size).lineHeight)
  }
}

extension Hashable where Self == Font {
  public static func textStyle(_ style: TextStyle, weight: Font.Weight = .regular) -> Font {
    style.font(weight: weight)
  }
}

private struct TextStyleModifier: ViewModifier {
  let style: TextStyle
  let weight: Font.Weight

  func body(content: Content) -> some View {
    content
      .font(style.font(weight: weight))
      .tracking(style.letterSpacing)
      .lineSpacing(style.lineSpacing)
      .padding(.vertical, style.lineSpacing / 2)
  }
}

extension View {
  public func textStyle(_ style: TextStyle, weight: Font.Weight = .regular) -> some View {
    modifier(TextStyleModifier(style: style, weight: weight))
  }
}

public struct Shadow: Sendable, Hashable {
  public let color: Color
  public let radius: CGFloat
  public let x: CGFloat
  public let y: CGFloat

  public init(color: Color, radius: CGFloat, x: CGFloat = 0, y: CGFloat = 0) {
    self.color = color
    self.radius = radius
    self.x = x
    self.y = y
  }
}

extension View {
  public func shadow(_ shadow: Shadow) -> some View {
    self.shadow(color: shadow.color, radius: shadow.radius, x: shadow.x, y: shadow.y)
  }
}
```

```swift title="swift/Theme/Tokens.swift"
import SwiftUI

extension Color {
  public static let surface = Color.adaptive(light: .init(0xFFFFFF), dark: .init(0x000000))
  public static let surfaceSecondary = Color.adaptive(light: .init(0xF5F5F7), dark: .init(0x161617))
  public static let surfaceTertiary = Color.adaptive(light: .init(0xE8E8ED), dark: .init(0x2C2C2E))
  public static let surfaceRaised = Color.adaptive(light: .init(0xFFFFFF), dark: .init(0x1D1D1F))
  public static let label = Color.adaptive(light: .init(0x1D1D1F), dark: .init(0xF5F5F7))
  public static let labelSecondary = Color.adaptive(light: .init(0x6E6E73), dark: .init(0xA1A1A6))
  public static let labelTertiary = Color.adaptive(light: .init(0x86868B), dark: .init(0x86868B))
  public static let labelQuaternary = Color.adaptive(light: .init(0xD2D2D7), dark: .init(0x424245))
  public static let control = Color.adaptive(light: .init(0x000000, 0.04), dark: .init(0xFFFFFF, 0.1))
  public static let controlPressed = Color.adaptive(light: .init(0x000000, 0.12), dark: .init(0xFFFFFF, 0.22))
  public static let controlSelected = Color.adaptive(light: .init(0x1D1D1F), dark: .init(0xF5F5F7))
  public static let controlDisabled = Color.adaptive(light: .init(0x000000, 0.03), dark: .init(0xFFFFFF, 0.05))
  public static let onControlSelected = Color.adaptive(light: .init(0xFFFFFF), dark: .init(0x000000))
  public static let itemPressed = Color.adaptive(light: .init(0x000000, 0.08), dark: .init(0xFFFFFF, 0.12))
  public static let itemSelected = Color.adaptive(light: .init(0x000000, 0.06), dark: .init(0xFFFFFF, 0.1))
  public static let separator = Color.adaptive(light: .init(0xD2D2D7), dark: .init(0x424245))
  public static let separatorStrong = Color.adaptive(light: .init(0x86868B), dark: .init(0x6E6E73))
  public static let accent = Color.adaptive(light: .init(0x0071E3), dark: .init(0x0071E3))
  public static let accentPressed = Color.adaptive(light: .init(0x005BB8), dark: .init(0x004D9E))
  public static let accentSelected = Color.adaptive(light: .init(0x0071E3), dark: .init(0x0071E3))
  public static let accentDisabled = Color.adaptive(light: .init(0x0071E3, 0.4), dark: .init(0x0071E3, 0.4))
  public static let onAccent = Color.adaptive(light: .init(0xFFFFFF), dark: .init(0xFFFFFF))
  public static let accentSurface = Color.adaptive(light: .init(0x0071E3, 0.09), dark: .init(0x0071E3, 0.18))
  public static let accentSurfacePressed = Color.adaptive(light: .init(0x0071E3, 0.18), dark: .init(0x0071E3, 0.3))
  public static let link = Color.adaptive(light: .init(0x0066CC), dark: .init(0x2997FF))
  public static let focus = Color.adaptive(light: .init(0x0071E3), dark: .init(0x0071E3))
  public static let scrim = Color.adaptive(light: .init(0x000000, 0.48), dark: .init(0x000000, 0.48))
  public static let media = Color.adaptive(light: .init(0x000000), dark: .init(0x000000))
  public static let onMedia = Color.adaptive(light: .init(0xFFFFFF), dark: .init(0xFFFFFF))
  public static let danger = Color.adaptive(light: .init(0xD0000A), dark: .init(0xFF5447))
  public static let dangerSurface = Color.adaptive(light: .init(0xD70015, 0.08), dark: .init(0xFF453A, 0.2))
  public static let dangerSurfacePressed = Color.adaptive(light: .init(0xD70015, 0.16), dark: .init(0xFF453A, 0.36))
  public static let success = Color.adaptive(light: .init(0x008009), dark: .init(0x30D158))
  public static let successSurface = Color.adaptive(light: .init(0xEFFAF1), dark: .init(0x30D158, 0.16))
  public static let warning = Color.adaptive(light: .init(0xB64400), dark: .init(0xFF9F0A))
  public static let warningSurface = Color.adaptive(light: .init(0xFFF5EA), dark: .init(0xFF9F0A, 0.16))
}

public enum Radius {
  public static let xs: CGFloat = 3
  public static let sm: CGFloat = 5
  public static let md: CGFloat = 8
  public static let lg: CGFloat = 10
  public static let xl: CGFloat = 12
  public static let xl2: CGFloat = 18
  public static let xl3: CGFloat = 28
  public static let full: CGFloat = 9999
}

extension TextStyle {
  public static let xs3 = TextStyle(size: 11, lineHeight: 13, letterSpacing: 0.066)
  public static let xs2 = TextStyle(size: 12, lineHeight: 16, letterSpacing: 0)
  public static let xs = TextStyle(size: 13, lineHeight: 18, letterSpacing: -0.078)
  public static let sm = TextStyle(size: 15, lineHeight: 20, letterSpacing: -0.24)
  public static let md = TextStyle(size: 16, lineHeight: 21, letterSpacing: -0.32)
  public static let base = TextStyle(size: 17, lineHeight: 22, letterSpacing: -0.442)
  public static let lg = TextStyle(size: 20, lineHeight: 25, letterSpacing: -0.46)
  public static let xl = TextStyle(size: 22, lineHeight: 28, letterSpacing: -0.264)
  public static let xl2 = TextStyle(size: 28, lineHeight: 34, letterSpacing: 0.392)
  public static let xl3 = TextStyle(size: 34, lineHeight: 41, letterSpacing: 0.408)

  public static let allCases: [TextStyle] = [.xs3, .xs2, .xs, .sm, .md, .base, .lg, .xl, .xl2, .xl3]
}

extension Shadow {
  public static let md = Shadow(color: .black.opacity(0.08), radius: 6, x: 2, y: 4)
  public static let lg = Shadow(color: .black.opacity(0.12), radius: 12, y: 4)
}
```

4. Copy the source and every file it uses:

```swift title="swift/Components/PageIndicator.swift"
import SwiftUI

public enum PageIndicatorSize: CaseIterable, Sendable {
  case sm, `default`

  var dot: CGFloat {
    switch self {
    case .sm: 6
    case .default: 8
    }
  }

  var activeWidth: CGFloat {
    switch self {
    case .sm: 16
    case .default: 24
    }
  }

  var spacing: CGFloat {
    switch self {
    case .sm: 6
    case .default: 8
    }
  }
}

public enum PageIndicatorVariant: CaseIterable, Sendable {
  case `default`, accent
}

struct PageIndicatorDot: Equatable, Sendable {
  let page: Int
  let scale: CGFloat
}

enum PageIndicatorMath {
  static let minimumVisible = 5

  static func window(count: Int, index: Int, maxVisible: Int) -> Range<Int> {
    let visible = max(maxVisible, minimumVisible)
    guard count > visible else { return 0..<max(count, 0) }
    let current = CarouselMath.clamp(index, count: count)
    let start = min(max(current - visible / 2, 0), count - visible)
    return start..<(start + visible)
  }

  static func dots(count: Int, index: Int, maxVisible: Int) -> [PageIndicatorDot] {
    let range = window(count: count, index: index, maxVisible: maxVisible)
    let hiddenBefore = range.lowerBound > 0
    let hiddenAfter = range.upperBound < count
    return range.map { page in
      let fromStart = page - range.lowerBound
      let fromEnd = range.upperBound - 1 - page
      var scale: CGFloat = 1
      if hiddenBefore && fromStart < 2 { scale = min(scale, fromStart == 0 ? 0.5 : 0.75) }
      if hiddenAfter && fromEnd < 2 { scale = min(scale, fromEnd == 0 ? 0.5 : 0.75) }
      return PageIndicatorDot(page: page, scale: scale)
    }
  }
}

public struct PageIndicator: View {
  public typealias Size = PageIndicatorSize
  public typealias Variant = PageIndicatorVariant

  let count: Int
  let index: Int
  let size: Size
  let variant: Variant
  let maxVisible: Int
  let onIndexChange: ((Int) -> Void)?

  @State private var taps = 0
  @Environment(\.accessibilityReduceMotion) private var reduceMotion

  public init(
    count: Int,
    index: Int,
    size: Size = .default,
    variant: Variant = .default,
    maxVisible: Int = 7,
    onIndexChange: ((Int) -> Void)? = nil
  ) {
    self.count = count
    self.index = index
    self.size = size
    self.variant = variant
    self.maxVisible = maxVisible
    self.onIndexChange = onIndexChange
  }

  public var body: some View {
    let current = CarouselMath.clamp(index, count: count)
    let dots = PageIndicatorMath.dots(count: count, index: current, maxVisible: maxVisible)
    HStack(spacing: size.spacing) {
      ForEach(dots, id: \.page) { dot in
        let active = dot.page == current
        Capsule()
          .fill(active ? activeColor : Color.labelQuaternary)
          .frame(width: active ? size.activeWidth : size.dot, height: size.dot)
          .scaleEffect(dot.scale)
          .padding(.vertical, size.dot)
          .contentShape(Rectangle())
          .onTapGesture {
            if let onIndexChange, dot.page != current {
              taps += 1
              onIndexChange(dot.page)
            }
          }
          .transition(.scale.combined(with: .opacity))
      }
    }
    .animation(reduceMotion ? nil : carouselAnimation, value: current)
    .hapticFeedback(.selection, trigger: taps)
    .accessibilityElement(children: .ignore)
    .accessibilityLabel(Text("Page"))
    .accessibilityValue(Text("\(current + 1) of \(count)"))
    .accessibilityAdjustableAction { direction in
      guard let onIndexChange else { return }
      switch direction {
      case .increment: if current < count - 1 { onIndexChange(current + 1) }
      case .decrement: if current > 0 { onIndexChange(current - 1) }
      @unknown default: break
      }
    }
  }

  private var activeColor: Color {
    switch variant {
    case .default: .label
    case .accent: .accent
    }
  }
}
```

```swift title="swift/Components/Button.swift"
import SwiftUI

public struct VariantButtonStyle: ButtonStyle {
  public enum Variant: CaseIterable, Sendable {
    case `default`, outline, secondary, tinted, ghost, plain, destructive, link
  }

  public enum Size: CaseIterable, Sendable {
    case `default`, xs, sm, lg, xl, icon, iconXs, iconSm, iconLg, iconXl

    var height: CGFloat {
      switch self {
      case .xs, .iconXs: 24
      case .sm, .iconSm: 32
      case .default, .icon: 36
      case .lg, .iconLg: 44
      case .xl, .iconXl: 56
      }
    }

    var horizontalPadding: CGFloat {
      switch self {
      case .xs: 11
      case .sm: 12
      case .default: 16
      case .lg: 22
      case .xl: 31
      case .icon, .iconXs, .iconSm, .iconLg, .iconXl: 0
      }
    }

    var spacing: CGFloat {
      switch self {
      case .xs, .sm, .iconXs, .iconSm: 4
      case .xl, .iconXl: 8
      default: 6
      }
    }

    var textStyle: TextStyle {
      switch self {
      case .xs, .iconXs: .xs2
      case .lg, .xl: .base
      default: .sm
      }
    }

    public var iconSize: CGFloat {
      switch self {
      case .xs, .iconXs: 12
      default: 16
      }
    }

    var blockRadius: CGFloat {
      switch self {
      case .xs, .iconXs: Radius.sm
      case .lg, .iconLg: Radius.lg
      case .xl, .iconXl: Radius.xl
      default: Radius.md
      }
    }

    var isIcon: Bool {
      switch self {
      case .icon, .iconXs, .iconSm, .iconLg, .iconXl: true
      default: false
      }
    }
  }

  let variant: Variant
  let size: Size
  let block: Bool
  var metrics: ButtonMetrics?

  public init(_ variant: Variant = .default, size: Size = .default, block: Bool = false) {
    self.variant = variant
    self.size = size
    self.block = block
  }

  init(_ variant: Variant, size: Size, metrics: ButtonMetrics) {
    self.variant = variant
    self.size = size
    self.block = false
    self.metrics = metrics
  }

  public func makeBody(configuration: Configuration) -> some View {
    StyledButton(configuration: configuration, variant: variant, size: size, block: block, metrics: metrics)
  }
}

struct ButtonMetrics: Sendable {
  var horizontalPadding: CGFloat
  var spacing: CGFloat
  var iconSize: CGFloat
  var textStyle: TextStyle
}

private struct StyledButton: View {
  let configuration: ButtonStyleConfiguration
  let variant: VariantButtonStyle.Variant
  let size: VariantButtonStyle.Size
  let block: Bool
  let metrics: ButtonMetrics?

  @Environment(\.colorScheme) private var colorScheme
  @Environment(\.isEnabled) private var isEnabled
  @Environment(\.buttonGroup) private var group

  var body: some View {
    let joined = group != nil && variant != .ghost && variant != .plain
    let rounded = RoundedRectangle(
      cornerRadius: block ? size.blockRadius : Radius.full,
      style: .continuous
    )
    let shape = joined ? AnyShape(Rectangle()) : AnyShape(rounded)
    configuration.label
      .labelStyle(ButtonLabelStyle(spacing: metrics?.spacing ?? size.spacing, iconSize: metrics?.iconSize ?? size.iconSize))
    .font((metrics?.textStyle ?? size.textStyle).font())
    .tracking((metrics?.textStyle ?? size.textStyle).letterSpacing)
    .underline(variant == .link && pressed && isEnabled)
    .lineLimit(1)
    .foregroundStyle(foreground)
    .padding(.horizontal, metrics?.horizontalPadding ?? size.horizontalPadding)
    .frame(width: size.isIcon && !block ? size.height : nil, height: size.height)
    .frame(maxWidth: block || group == .vertical ? .infinity : nil)
    .background(background, in: shape)
    .overlay {
      if variant == .outline && !joined {
        rounded.strokeBorder(Color.separator)
      }
    }
    .contentShape(shape)
    .anchorPreference(key: ButtonGroupFramesKey.self, value: .bounds) { anchor in
      joined ? [ButtonGroupFrame(bounds: anchor, outlined: variant == .outline)] : []
    }
  }

  private var isDark: Bool { colorScheme == .dark }
  private var pressed: Bool { configuration.isPressed }

  private var foreground: Color {
    switch variant {
    case .default:
      .onAccent
    case .outline, .secondary, .ghost:
      isEnabled ? .label : .labelQuaternary
    case .tinted, .plain:
      isEnabled ? .link : .link.opacity(0.4)
    case .destructive:
      isEnabled ? .danger : .danger.opacity(0.4)
    case .link:
      isEnabled ? .link : .labelQuaternary
    }
  }

  private var background: Color {
    switch variant {
    case .default:
      !isEnabled ? .accentDisabled : pressed ? .accentPressed : .accent
    case .outline:
      isEnabled && pressed ? .itemPressed : isDark ? .clear : .surface
    case .secondary:
      !isEnabled ? .controlDisabled : pressed ? .controlPressed : .control
    case .tinted:
      isEnabled && pressed ? .accentSurfacePressed : .accentSurface
    case .ghost:
      isEnabled && pressed ? .itemPressed : .clear
    case .plain:
      isEnabled && pressed ? .itemPressed : .clear
    case .destructive:
      isEnabled && pressed ? .dangerSurfacePressed : .dangerSurface
    case .link:
      .clear
    }
  }
}

struct ButtonLabelStyle: LabelStyle {
  let spacing: CGFloat
  let iconSize: CGFloat

  func makeBody(configuration: Configuration) -> some View {
    HStack(spacing: spacing) {
      configuration.icon
        .frame(width: iconSize, height: iconSize)
      configuration.title
    }
  }
}

extension ButtonStyle where Self == VariantButtonStyle {
  public static func variant(
    _ variant: VariantButtonStyle.Variant = .default,
    size: VariantButtonStyle.Size = .default,
    block: Bool = false
  ) -> VariantButtonStyle {
    VariantButtonStyle(variant, size: size, block: block)
  }
}
```

```swift title="swift/Components/ButtonGroup.swift"
import SwiftUI

extension EnvironmentValues {
  @Entry var buttonGroup: Axis? = nil
  @Entry var buttonGroupSize: CGSize = .zero
}

enum ButtonGroupSpace: Hashable {
  case group
}

struct ButtonGroupFrame {
  let bounds: Anchor<CGRect>
  let outlined: Bool
}

struct ButtonGroupFramesKey: PreferenceKey {
  static var defaultValue: [ButtonGroupFrame] { [] }

  static func reduce(value: inout [ButtonGroupFrame], nextValue: () -> [ButtonGroupFrame]) {
    value.append(contentsOf: nextValue())
  }
}

struct ButtonGroupNestedKey: PreferenceKey {
  static var defaultValue: Bool { false }

  static func reduce(value: inout Bool, nextValue: () -> Bool) {
    value = value || nextValue()
  }
}

public struct ButtonGroup<Content: View>: View {
  let orientation: Axis
  let content: Content

  @State private var nested = false
  @State private var size: CGSize = .zero

  public init(orientation: Axis = .horizontal, @ViewBuilder content: () -> Content) {
    self.orientation = orientation
    self.content = content()
  }

  public var body: some View {
    let shape = orientation == .horizontal
      ? AnyShape(Capsule())
      : AnyShape(RoundedRectangle(cornerRadius: Radius.xl2, style: .continuous))
    stack
      .coordinateSpace(.named(ButtonGroupSpace.group))
      .onGeometryChange(for: CGSize.self) { $0.size } action: { size = $0 }
      .environment(\.buttonGroup, nested ? nil : orientation)
      .environment(\.buttonGroupSize, size)
      .onPreferenceChange(ButtonGroupNestedKey.self) { nested = $0 }
      .modifier(ButtonGroupClip(shape: nested ? nil : shape))
      .overlayPreferenceValue(ButtonGroupFramesKey.self) { frames in
        if !nested {
          GeometryReader { proxy in
            outline(frames.map { (proxy[$0.bounds], $0.outlined) }, shape: shape)
          }
        }
      }
      .transformPreference(ButtonGroupFramesKey.self) { $0 = [] }
      .transformPreference(ButtonGroupNestedKey.self) { $0 = true }
      .fixedSize(horizontal: orientation == .vertical, vertical: orientation == .horizontal)
      .accessibilityElement(children: .contain)
  }

  @ViewBuilder private var stack: some View {
    switch orientation {
    case .horizontal:
      HStack(spacing: nested ? 8 : 0) { content }
    case .vertical:
      VStack(spacing: nested ? 8 : 0) { content }
    }
  }

  @ViewBuilder private func outline(_ frames: [(CGRect, Bool)], shape: AnyShape) -> some View {
    if frames.contains(where: \.1) {
      ZStack(alignment: .topLeading) {
        shape
          .stroke(Color.separator, lineWidth: 1)
          .padding(0.5)
          .mask {
            Path { path in
              for (rect, outlined) in frames where outlined {
                path.addRect(rect)
              }
            }
          }
        ForEach(Array(frames.dropLast().enumerated()), id: \.offset) { _, frame in
          if frame.1 {
            divider(frame.0)
          }
        }
      }
      .clipShape(shape)
      .allowsHitTesting(false)
    }
  }

  private func divider(_ rect: CGRect) -> some View {
    let horizontal = orientation == .horizontal
    return Rectangle()
      .fill(Color.separator)
      .frame(width: horizontal ? 1 : rect.width, height: horizontal ? rect.height : 1)
      .position(
        x: horizontal ? rect.maxX - 0.5 : rect.midX,
        y: horizontal ? rect.midY : rect.maxY - 0.5
      )
  }
}

struct ButtonGroupItem<Content: View>: View {
  let radius: CGFloat
  let content: (UnevenRoundedRectangle) -> Content

  @State private var frame: CGRect = .zero
  @Environment(\.buttonGroup) private var group
  @Environment(\.buttonGroupSize) private var groupSize

  init(radius: CGFloat, @ViewBuilder content: @escaping (UnevenRoundedRectangle) -> Content) {
    self.radius = radius
    self.content = content
  }

  var body: some View {
    if let group {
      content(shape(group))
        .onGeometryChange(for: CGRect.self) { $0.frame(in: .named(ButtonGroupSpace.group)) } action: { frame = $0 }
    } else {
      content(UnevenRoundedRectangle(cornerRadii: RectangleCornerRadii(
        topLeading: radius,
        bottomLeading: radius,
        bottomTrailing: radius,
        topTrailing: radius
      ), style: .continuous))
    }
  }

  private func shape(_ group: Axis) -> UnevenRoundedRectangle {
    let horizontal = group == .horizontal
    let first = horizontal ? frame.minX <= 0.5 : frame.minY <= 0.5
    let last = horizontal
      ? frame.maxX >= groupSize.width - 0.5
      : frame.maxY >= groupSize.height - 0.5
    let round = horizontal ? frame.height / 2 : Radius.xl2
    let start: CGFloat = first ? round : 0
    let end: CGFloat = last ? round : 0
    let radii = horizontal
      ? RectangleCornerRadii(topLeading: start, bottomLeading: start, bottomTrailing: end, topTrailing: end)
      : RectangleCornerRadii(topLeading: start, bottomLeading: end, bottomTrailing: end, topTrailing: start)
    return UnevenRoundedRectangle(cornerRadii: radii, style: .continuous)
  }
}

private struct ButtonGroupClip: ViewModifier {
  let shape: AnyShape?

  func body(content: Content) -> some View {
    if let shape {
      content.clipShape(shape)
    } else {
      content
    }
  }
}

public struct ButtonGroupText<Content: View>: View {
  let content: Content

  @Environment(\.buttonGroup) private var group

  public init(@ViewBuilder content: () -> Content) {
    self.content = content()
  }

  public var body: some View {
    let shape = group == nil ? AnyShape(Capsule()) : AnyShape(Rectangle())
    HStack(spacing: 8) {
      content
    }
    .labelStyle(ButtonLabelStyle(spacing: 8, iconSize: 16))
    .scaledFont(.sm)
    .lineLimit(1)
    .foregroundStyle(Color.label)
    .padding(.horizontal, 10)
    .frame(minHeight: 36)
    .frame(maxWidth: group == .vertical ? .infinity : nil, maxHeight: group == .horizontal ? .infinity : nil)
    .background(Color.control, in: shape)
    .anchorPreference(key: ButtonGroupFramesKey.self, value: .bounds) { anchor in
      group == nil ? [] : [ButtonGroupFrame(bounds: anchor, outlined: false)]
    }
  }
}

extension ButtonGroupText where Content == Text {
  public init(_ title: LocalizedStringKey) {
    self.init { Text(title) }
  }

  public init(verbatim title: String) {
    self.init { Text(verbatim: title) }
  }
}

public struct ButtonGroupSeparator: View {
  let orientation: Axis

  public init(_ orientation: Axis = .vertical) {
    self.orientation = orientation
  }

  public var body: some View {
    let vertical = orientation == .vertical
    Rectangle()
      .fill(Color.label.opacity(0.2))
      .frame(width: vertical ? 1 : nil, height: vertical ? nil : 1)
      .padding(vertical ? .vertical : .horizontal, 9)
      .frame(maxWidth: vertical ? nil : .infinity, maxHeight: vertical ? .infinity : nil)
      .padding(vertical ? .trailing : .bottom, -1)
      .zIndex(1)
      .accessibilityHidden(true)
  }
}
```

```swift title="swift/Components/Carousel.swift"
import PhosphorSwift
import SwiftUI

public enum CarouselOrientation: CaseIterable, Sendable {
  case horizontal, vertical
}

public enum CarouselDotsVariant: CaseIterable, Sendable {
  case `default`, plain
}

let carouselAnimation = Animation.timingCurve(0.32, 0.72, 0, 1, duration: 0.5)

enum CarouselMath {
  static func clamp(_ index: Int, count: Int) -> Int {
    count == 0 ? 0 : min(max(index, 0), count - 1)
  }

  static func step(from index: Int, by delta: Int, count: Int, loop: Bool) -> Int? {
    guard count > 0 else { return nil }
    let next = index + delta
    if next >= 0 && next < count { return next }
    guard loop, count > 1 else { return nil }
    return ((next % count) + count) % count
  }

  static func autoplayTarget(from index: Int, count: Int, loop: Bool) -> Int? {
    guard count > 1 else { return nil }
    return step(from: index, by: 1, count: count, loop: loop) ?? 0
  }
}

@MainActor
@Observable
public final class CarouselController {
  public private(set) var selectedIndex = 0
  public private(set) var count = 0
  public internal(set) var isPlaying = false

  var keys: [UUID] = []
  var loop = false
  var reduceMotion = false
  var autoplayEnabled = false
  var autoplayDelay: Duration = .seconds(5)
  var autoplayStart: Date?

  public init() {}

  public var canScrollPrev: Bool {
    CarouselMath.step(from: selectedIndex, by: -1, count: count, loop: loop) != nil
  }

  public var canScrollNext: Bool {
    CarouselMath.step(from: selectedIndex, by: 1, count: count, loop: loop) != nil
  }

  public func scrollTo(_ index: Int, animated: Bool = true) {
    let target = CarouselMath.clamp(index, count: count)
    guard target != selectedIndex else { return }
    if animated && !reduceMotion {
      withAnimation(carouselAnimation) { selectedIndex = target }
    } else {
      selectedIndex = target
    }
  }

  public func scrollPrev() {
    if let target = CarouselMath.step(from: selectedIndex, by: -1, count: count, loop: loop) {
      scrollTo(target)
    }
  }

  public func scrollNext() {
    if let target = CarouselMath.step(from: selectedIndex, by: 1, count: count, loop: loop) {
      scrollTo(target)
    }
  }

  public func setPlaying(_ playing: Bool) {
    isPlaying = autoplayEnabled && playing
  }

  func register(_ keys: [UUID]) {
    self.keys = keys
    count = keys.count
    selectedIndex = CarouselMath.clamp(selectedIndex, count: count)
  }

  var position: UUID? {
    get { keys.indices.contains(selectedIndex) ? keys[selectedIndex] : nil }
    set {
      if let newValue, let index = keys.firstIndex(of: newValue) {
        selectedIndex = index
      }
    }
  }
}

extension EnvironmentValues {
  @Entry var carousel: CarouselController? = nil
  @Entry var carouselOrientation: CarouselOrientation = .horizontal
  @Entry var carouselSpacing: CGFloat = 16
}

struct CarouselKeysKey: PreferenceKey {
  static var defaultValue: [UUID] { [] }

  static func reduce(value: inout [UUID], nextValue: () -> [UUID]) {
    value.append(contentsOf: nextValue())
  }
}

private struct CarouselAutoplayKey: Hashable {
  let index: Int
  let count: Int
  let running: Bool
}

public struct Carousel<Content: View>: View {
  let orientation: CarouselOrientation
  let loop: Bool
  let autoplay: Duration?
  let external: CarouselController?
  let onSelect: ((Int) -> Void)?
  let content: Content

  @State private var local = CarouselController()
  @Environment(\.accessibilityReduceMotion) private var reduceMotion
  @Environment(\.scenePhase) private var scenePhase

  public init(
    orientation: CarouselOrientation = .horizontal,
    loop: Bool = false,
    autoplay: Duration? = nil,
    controller: CarouselController? = nil,
    onSelect: ((Int) -> Void)? = nil,
    @ViewBuilder content: () -> Content
  ) {
    self.orientation = orientation
    self.loop = loop
    self.autoplay = autoplay
    self.external = controller
    self.onSelect = onSelect
    self.content = content()
  }

  public var body: some View {
    let controller = external ?? local
    let running = controller.isPlaying && scenePhase != .background
    VStack(spacing: 0) {
      content
    }
    .environment(\.carousel, controller)
    .environment(\.carouselOrientation, orientation)
    .onAppear {
      controller.loop = loop
      controller.reduceMotion = reduceMotion
      controller.autoplayEnabled = autoplay != nil
      controller.autoplayDelay = autoplay ?? .seconds(5)
      controller.isPlaying = autoplay != nil && !reduceMotion
    }
    .onChange(of: loop) { _, value in controller.loop = value }
    .onChange(of: reduceMotion) { _, value in controller.reduceMotion = value }
    .onChange(of: controller.selectedIndex) { _, value in onSelect?(value) }
    .task(id: CarouselAutoplayKey(index: controller.selectedIndex, count: controller.count, running: running)) {
      guard running, let delay = autoplay else {
        controller.autoplayStart = nil
        return
      }
      controller.autoplayStart = .now
      do {
        try await Task.sleep(for: delay)
      } catch {
        return
      }
      if let target = CarouselMath.autoplayTarget(from: controller.selectedIndex, count: controller.count, loop: controller.loop) {
        controller.scrollTo(target)
      }
    }
    .accessibilityElement(children: .contain)
  }
}

public struct CarouselContent<Content: View>: View {
  let spacing: CGFloat
  let content: Content

  @State private var keys: [UUID] = []
  @Environment(\.carousel) private var carousel
  @Environment(\.carouselOrientation) private var orientation

  public init(spacing: CGFloat = 16, @ViewBuilder content: () -> Content) {
    self.spacing = spacing
    self.content = content()
  }

  public var body: some View {
    let horizontal = orientation == .horizontal
    ScrollView(horizontal ? .horizontal : .vertical) {
      Group {
        if horizontal {
          HStack(spacing: spacing) { content }
        } else {
          VStack(spacing: spacing) { content }
        }
      }
      .scrollTargetLayout()
    }
    .scrollIndicators(.hidden)
    .scrollTargetBehavior(.viewAligned(limitBehavior: .always))
    .scrollPosition(id: position)
    .environment(\.carouselSpacing, spacing)
    .onPreferenceChange(CarouselKeysKey.self) { value in keys = value }
    .onChange(of: keys, initial: true) { _, value in carousel?.register(value) }
  }

  private var position: Binding<UUID?> {
    let carousel = carousel
    return Binding(
      get: { carousel?.position },
      set: { carousel?.position = $0 }
    )
  }
}

public struct CarouselItem<Content: View>: View {
  let basis: CGFloat
  let content: Content

  @State private var key = UUID()
  @Environment(\.carousel) private var carousel
  @Environment(\.carouselOrientation) private var orientation
  @Environment(\.carouselSpacing) private var spacing

  public init(basis: CGFloat = 1, @ViewBuilder content: () -> Content) {
    self.basis = basis
    self.content = content()
  }

  public var body: some View {
    let index = carousel?.keys.firstIndex(of: key)
    content
      .containerRelativeFrame(orientation == .horizontal ? .horizontal : .vertical) { length, _ in
        max(0, (length + spacing) * min(max(basis, 0), 1) - spacing)
      }
      .id(key)
      .preference(key: CarouselKeysKey.self, value: [key])
      .accessibilityElement(children: .contain)
      .accessibilityLabel(index.map { Text("Slide \($0 + 1) of \(carousel?.count ?? 0)") } ?? Text(verbatim: ""))
  }
}

public struct CarouselPrevious: View {
  let variant: VariantButtonStyle.Variant
  let size: VariantButtonStyle.Size

  @Environment(\.carousel) private var carousel
  @Environment(\.carouselOrientation) private var orientation

  public init(variant: VariantButtonStyle.Variant = .secondary, size: VariantButtonStyle.Size = .icon) {
    self.variant = variant
    self.size = size
  }

  public var body: some View {
    Button {
      carousel?.scrollPrev()
    } label: {
      (orientation == .horizontal ? Ph.caretLeft.bold : Ph.caretUp.bold)
        .frame(width: 16, height: 16)
        .flipsForRightToLeftLayoutDirection(orientation == .horizontal)
    }
    .buttonStyle(.variant(variant, size: size))
    .disabled(!(carousel?.canScrollPrev ?? false))
    .accessibilityLabel(Text("Previous slide"))
  }
}

public struct CarouselNext: View {
  let variant: VariantButtonStyle.Variant
  let size: VariantButtonStyle.Size

  @Environment(\.carousel) private var carousel
  @Environment(\.carouselOrientation) private var orientation

  public init(variant: VariantButtonStyle.Variant = .secondary, size: VariantButtonStyle.Size = .icon) {
    self.variant = variant
    self.size = size
  }

  public var body: some View {
    Button {
      carousel?.scrollNext()
    } label: {
      (orientation == .horizontal ? Ph.caretRight.bold : Ph.caretDown.bold)
        .frame(width: 16, height: 16)
        .flipsForRightToLeftLayoutDirection(orientation == .horizontal)
    }
    .buttonStyle(.variant(variant, size: size))
    .disabled(!(carousel?.canScrollNext ?? false))
    .accessibilityLabel(Text("Next slide"))
  }
}

public struct CarouselControls<Content: View>: View {
  let content: Content

  public init(@ViewBuilder content: () -> Content) {
    self.content = content()
  }

  public var body: some View {
    HStack(spacing: 12) {
      content
    }
    .padding(.top, 24)
  }
}

public struct CarouselDots: View {
  let variant: CarouselDotsVariant

  @Environment(\.carousel) private var carousel
  @Environment(\.accessibilityReduceMotion) private var reduceMotion

  public init(variant: CarouselDotsVariant = .default) {
    self.variant = variant
  }

  public var body: some View {
    let count = carousel?.count ?? 0
    let selected = carousel?.selectedIndex ?? 0
    let autoplay = carousel?.autoplayEnabled ?? false
    HStack(spacing: 16) {
      ForEach(0..<count, id: \.self) { index in
        let active = index == selected
        Button {
          carousel?.scrollTo(index)
        } label: {
          Capsule()
            .fill(active ? (autoplay ? Color.labelTertiary : .label) : .labelTertiary)
            .frame(width: active ? 24 : 8, height: 8)
            .overlay(alignment: .leading) {
              if active && autoplay, let carousel {
                CarouselDotsFill(carousel: carousel)
              }
            }
            .clipShape(Capsule())
            .padding(8)
            .contentShape(Rectangle())
        }
        .buttonStyle(.plain)
        .padding(-8)
        .accessibilityLabel(Text("Go to slide \(index + 1)"))
        .accessibilityAddTraits(active ? .isSelected : [])
      }
    }
    .animation(reduceMotion ? nil : carouselAnimation, value: selected)
    .frame(height: 36)
    .padding(.horizontal, variant == .default ? 16 : 0)
    .background {
      if variant == .default {
        Capsule().fill(Color.control)
      }
    }
  }
}

private struct CarouselDotsFill: View {
  let carousel: CarouselController

  var body: some View {
    TimelineView(.animation(paused: carousel.autoplayStart == nil)) { timeline in
      GeometryReader { proxy in
        Capsule()
          .fill(Color.label)
          .frame(width: proxy.size.width * fraction(at: timeline.date))
      }
    }
  }

  private func fraction(at date: Date) -> CGFloat {
    guard carousel.isPlaying else { return 1 }
    guard let start = carousel.autoplayStart else { return 0 }
    let delay = carousel.autoplayDelay / .seconds(1)
    guard delay > 0 else { return 1 }
    return min(max(date.timeIntervalSince(start) / delay, 0), 1)
  }
}

public struct CarouselPlayButton: View {
  let variant: VariantButtonStyle.Variant
  let size: VariantButtonStyle.Size

  @Environment(\.carousel) private var carousel

  public init(variant: VariantButtonStyle.Variant = .secondary, size: VariantButtonStyle.Size = .iconSm) {
    self.variant = variant
    self.size = size
  }

  public var body: some View {
    if let carousel, carousel.autoplayEnabled {
      let playing = carousel.isPlaying
      Button {
        carousel.setPlaying(!playing)
      } label: {
        (playing ? Ph.pause.fill : Ph.play.fill)
          .frame(width: 14, height: 14)
      }
      .buttonStyle(.variant(variant, size: size))
      .accessibilityLabel(playing ? Text("Pause slideshow") : Text("Play slideshow"))
    }
  }
}
```

```swift title="swift/Components/Checkbox.swift"
import PhosphorSwift
import SwiftUI

extension Shadow {
  static let control = Shadow(color: .black.opacity(0.08), radius: 0.5, y: 0.5)
  static let thumb = Shadow(color: .black.opacity(0.12), radius: 1.5, y: 1)
}

struct SelectionIndicator<Mark: View>: View {
  let checked: Bool
  let pressed: Bool
  let cornerRadius: CGFloat
  let mark: Mark

  @Environment(\.isEnabled) private var isEnabled
  @Environment(\.isInvalid) private var invalid
  @Environment(\.colorScheme) private var colorScheme

  init(checked: Bool, pressed: Bool, cornerRadius: CGFloat, @ViewBuilder mark: () -> Mark) {
    self.checked = checked
    self.pressed = pressed
    self.cornerRadius = cornerRadius
    self.mark = mark()
  }

  var body: some View {
    let shape = RoundedRectangle(cornerRadius: cornerRadius, style: .continuous)
    ZStack {
      shape.fill(fill)
      shape.strokeBorder(border, lineWidth: 1)
      if checked {
        mark
      }
    }
    .frame(width: 16, height: 16)
    .shadow(raised ? .control : Shadow(color: .clear, radius: 0))
  }

  private var isDark: Bool { colorScheme == .dark }

  private var raised: Bool { !checked && isEnabled && !isDark }

  private var fill: Color {
    if checked {
      return !isEnabled ? .accentDisabled : pressed ? .accentPressed : .accent
    }
    if !isEnabled { return .controlDisabled }
    if isDark { return pressed ? .labelTertiary.opacity(0.6) : .labelQuaternary }
    return pressed ? .control : .surface
  }

  private var border: Color {
    if checked {
      return !isEnabled ? .clear : pressed ? .accentPressed : .accent
    }
    if !isEnabled { return isDark ? .clear : .label.opacity(0.1) }
    if invalid { return .danger }
    return isDark ? .clear : .label.opacity(0.25)
  }
}

struct PressReader<Content: View>: ButtonStyle {
  let content: (Bool) -> Content

  init(@ViewBuilder content: @escaping (Bool) -> Content) {
    self.content = content
  }

  func makeBody(configuration: Configuration) -> some View {
    content(configuration.isPressed)
  }
}

public struct CheckboxStyle: ToggleStyle {
  public init() {}

  public func makeBody(configuration: Configuration) -> some View {
    HapticButton(style: PressReader { pressed in
      HStack(spacing: 12) {
        SelectionIndicator(
          checked: configuration.isOn || configuration.isMixed,
          pressed: pressed,
          cornerRadius: 4
        ) {
          (configuration.isMixed ? Ph.minus.regular : Ph.check.regular)
            .frame(width: 14, height: 14)
            .foregroundStyle(Color.onAccent)
        }
        configuration.label
      }
      .contentShape(Rectangle().inset(by: -8))
    }) {
      configuration.isOn.toggle()
      return true
    }
    .accessibilityElement(children: .combine)
    .accessibilityRemoveTraits(.isButton)
    .accessibilityAddTraits(.isToggle)
    .accessibilityValue(
      configuration.isMixed
        ? Text("Mixed")
        : configuration.isOn ? Text("Checked") : Text("Unchecked")
    )
  }
}

extension ToggleStyle where Self == CheckboxStyle {
  public static var checkbox: CheckboxStyle { CheckboxStyle() }
}
```

```swift title="swift/Components/Field.swift"
import SwiftUI

extension EnvironmentValues {
  @Entry public var isInvalid = false
  @Entry var fieldInset = false
  @Entry var fieldGroupInset = false
  @Entry var fieldSetInset = false
}

extension View {
  public func invalid(_ isInvalid: Bool = true) -> some View {
    environment(\.isInvalid, isInvalid)
  }
}

public enum FieldOrientation: CaseIterable, Sendable {
  case vertical, horizontal
}

public struct Field<Content: View>: View {
  let orientation: FieldOrientation
  let invalid: Bool?
  let content: Content

  @Environment(\.fieldGroupInset) private var inset
  @Environment(\.isInvalid) private var inheritedInvalid

  public init(
    orientation: FieldOrientation = .vertical,
    invalid: Bool? = nil,
    @ViewBuilder content: () -> Content
  ) {
    self.orientation = orientation
    self.invalid = invalid
    self.content = content()
  }

  public var body: some View {
    Group {
      switch orientation {
      case .vertical:
        VStack(alignment: .leading, spacing: 12) { content }
      case .horizontal:
        HStack(alignment: .center, spacing: 12) { content }
      }
    }
    .frame(maxWidth: .infinity, alignment: .leading)
    .padding(.horizontal, inset ? 16 : 0)
    .padding(.vertical, inset ? 6 : 0)
    .frame(minHeight: inset ? 44 : nil)
    .overlay(alignment: .top) {
      if inset {
        Color.separator
          .frame(height: 1)
          .padding(.leading, 16)
          .offset(y: -1)
      }
    }
    .environment(\.fieldInset, inset)
    .environment(\.fieldGroupInset, false)
    .environment(\.isInvalid, invalid ?? inheritedInvalid)
  }
}

public struct FieldContent<Content: View>: View {
  let content: Content

  public init(@ViewBuilder content: () -> Content) {
    self.content = content()
  }

  public var body: some View {
    VStack(alignment: .leading, spacing: 4) {
      content
    }
    .frame(maxWidth: .infinity, alignment: .leading)
  }
}

public struct FieldTitle: View {
  let text: Text

  @Environment(\.isEnabled) private var isEnabled

  public init(_ title: LocalizedStringKey) {
    text = Text(title)
  }

  public init<S: StringProtocol>(_ title: S) {
    text = Text(title)
  }

  public var body: some View {
    text
      .scaledTextStyle(.base, weight: .semibold)
      .foregroundStyle(isEnabled ? Color.label : .labelQuaternary)
  }
}

public struct FieldDescription: View {
  let text: Text

  @Environment(\.fieldSetInset) private var inset

  public init(_ description: LocalizedStringKey) {
    text = Text(description)
  }

  public init<S: StringProtocol>(_ description: S) {
    text = Text(description)
  }

  public var body: some View {
    text
      .scaledTextStyle(inset ? .xs : .sm)
      .foregroundStyle(Color.labelSecondary)
      .multilineTextAlignment(.leading)
      .fixedSize(horizontal: false, vertical: true)
      .padding(.leading, inset ? 16 : 0)
  }
}

public struct FieldError: View {
  let messages: [String]
  let text: Text?

  public init(_ message: LocalizedStringKey) {
    messages = []
    text = Text(message)
  }

  public init(errors: [String?]) {
    var seen = Set<String>()
    messages = errors.compactMap { $0 }.filter { !$0.isEmpty && seen.insert($0).inserted }
    text = nil
  }

  public var body: some View {
    if let content {
      content
        .scaledTextStyle(.sm)
        .foregroundStyle(Color.danger)
        .multilineTextAlignment(.leading)
        .fixedSize(horizontal: false, vertical: true)
    }
  }

  private var content: Text? {
    if let text { return text }
    switch messages.count {
    case 0: return nil
    case 1: return Text(verbatim: messages[0])
    default: return Text(verbatim: messages.map { "\u{2022} \($0)" }.joined(separator: "\n"))
    }
  }
}

public enum FieldGroupVariant: CaseIterable, Sendable {
  case `default`, inset
}

public struct FieldGroup<Content: View>: View {
  let variant: FieldGroupVariant
  let content: Content

  public init(_ variant: FieldGroupVariant = .default, @ViewBuilder content: () -> Content) {
    self.variant = variant
    self.content = content()
  }

  public var body: some View {
    styled
      .environment(\.fieldGroupInset, variant == .inset)
      .environment(\.fieldSetInset, false)
      .transformPreference(FieldSetInsetKey.self) { $0 = variant == .inset }
  }

  @ViewBuilder private var styled: some View {
    let stack = VStack(alignment: .leading, spacing: variant == .inset ? 0 : 28) {
      content
    }
    .frame(maxWidth: .infinity, alignment: .leading)
    if variant == .inset {
      let shape = RoundedRectangle(cornerRadius: Radius.xl2, style: .continuous)
      stack
        .background(Color.surfaceSecondary, in: shape)
        .clipShape(shape)
    } else {
      stack
    }
  }
}

struct FieldSetInsetKey: PreferenceKey {
  static let defaultValue = false

  static func reduce(value: inout Bool, nextValue: () -> Bool) {
    value = value || nextValue()
  }
}

public struct FieldSet<Content: View>: View {
  let content: Content

  @State private var inset = false

  public init(@ViewBuilder content: () -> Content) {
    self.content = content()
  }

  public var body: some View {
    VStack(alignment: .leading, spacing: inset ? 8 : 24) {
      content
    }
    .frame(maxWidth: .infinity, alignment: .leading)
    .environment(\.fieldSetInset, inset)
    .onPreferenceChange(FieldSetInsetKey.self) { inset = $0 }
    .transformPreference(FieldSetInsetKey.self) { $0 = false }
    .accessibilityElement(children: .contain)
  }
}

public struct FieldLegend: View {
  public enum Variant: CaseIterable, Sendable {
    case legend, label
  }

  let text: Text
  let variant: Variant

  @Environment(\.fieldSetInset) private var inset
  @Environment(\.isEnabled) private var isEnabled

  public init(_ title: LocalizedStringKey, variant: Variant = .legend) {
    text = Text(title)
    self.variant = variant
  }

  public init<S: StringProtocol>(_ title: S, variant: Variant = .legend) {
    text = Text(title)
    self.variant = variant
  }

  public var body: some View {
    Group {
      if inset {
        text
          .textCase(.uppercase)
          .scaledTextStyle(.xs)
          .foregroundStyle(isEnabled ? Color.labelSecondary : .labelQuaternary)
          .padding(.leading, 16)
      } else {
        text
          .scaledTextStyle(.base, weight: .semibold)
          .foregroundStyle(isEnabled ? Color.label : .labelQuaternary)
          .padding(.bottom, 12)
      }
    }
    .accessibilityAddTraits(variant == .legend ? .isHeader : [])
  }
}

public struct FieldSeparator<Content: View>: View {
  let content: Content

  public init(@ViewBuilder content: () -> Content) {
    self.content = content()
  }

  public var body: some View {
    ZStack {
      Separator()
      content
        .scaledTextStyle(.sm)
        .foregroundStyle(Color.labelSecondary)
        .padding(.horizontal, 8)
        .background(Color.surface)
    }
    .frame(minHeight: 20)
    .padding(.vertical, -8)
  }
}

extension FieldSeparator where Content == EmptyView {
  public init() {
    self.init { EmptyView() }
  }
}

extension FieldSeparator where Content == Text {
  public init(_ title: LocalizedStringKey) {
    self.init { Text(title) }
  }
}
```

```swift title="swift/Components/Haptics.swift"
import SwiftUI

extension EnvironmentValues {
  @Entry public var hapticsEnabled = true
}

extension View {
  public func haptics(_ enabled: Bool) -> some View {
    environment(\.hapticsEnabled, enabled)
  }

  func hapticFeedback<Trigger: Equatable>(_ feedback: SensoryFeedback, trigger: Trigger) -> some View {
    modifier(HapticFeedbackModifier(feedback: feedback, trigger: trigger) { _, _ in true })
  }

  func hapticFeedback<Trigger: Equatable>(
    _ feedback: SensoryFeedback,
    trigger: Trigger,
    condition: @escaping (Trigger, Trigger) -> Bool
  ) -> some View {
    modifier(HapticFeedbackModifier(feedback: feedback, trigger: trigger, condition: condition))
  }
}

private struct HapticFeedbackModifier<Trigger: Equatable>: ViewModifier {
  let feedback: SensoryFeedback
  let trigger: Trigger
  let condition: (Trigger, Trigger) -> Bool

  @Environment(\.hapticsEnabled) private var enabled

  func body(content: Content) -> some View {
    let enabled = enabled
    let condition = condition
    content.sensoryFeedback(feedback, trigger: trigger) { old, new in
      enabled && condition(old, new)
    }
  }
}

enum HapticMoments {
  static func step(_ value: Double, bounds: ClosedRange<Double>, step: Double?) -> Int? {
    guard let step, step > 0 else { return nil }
    return Int(((value - bounds.lowerBound) / step).rounded())
  }

  static func lifted<Value: Equatable>(_ old: Value?, _ new: Value?) -> Bool {
    new != nil && old != new
  }

  static func crossed<Value: Equatable>(_ old: Value?, _ new: Value?) -> Bool {
    old == nil && new != nil
  }

  static func moved(_ old: Int?, _ new: Int?) -> Bool {
    guard let old, let new else { return false }
    return old != new
  }
}

struct HapticButton<Style: ButtonStyle>: View {
  let feedback: SensoryFeedback
  let action: () -> Bool
  let style: Style

  @State private var count = 0

  init(_ feedback: SensoryFeedback = .selection, style: Style, action: @escaping () -> Bool) {
    self.feedback = feedback
    self.style = style
    self.action = action
  }

  var body: some View {
    Button {
      if action() { count += 1 }
    } label: {
      EmptyView()
    }
    .buttonStyle(style)
    .hapticFeedback(feedback, trigger: count)
  }
}
```

```swift title="swift/Components/Separator.swift"
import SwiftUI

public struct Separator: View {
  let orientation: Axis

  public init(_ orientation: Axis = .horizontal) {
    self.orientation = orientation
  }

  public var body: some View {
    Rectangle()
      .fill(Color.separator)
      .frame(width: orientation == .vertical ? 1 : nil, height: orientation == .horizontal ? 1 : nil)
      .frame(maxWidth: orientation == .horizontal ? .infinity : nil, maxHeight: orientation == .vertical ? .infinity : nil)
      .accessibilityHidden(true)
  }
}
```

```swift title="swift/Components/TextVariant.swift"
import SwiftUI

public enum TextVariant: CaseIterable, Sendable {
  case `default`, h1, h2, h3, h4, p, blockquote, code, lead, large, small, muted

  var style: TextStyle {
    switch self {
    case .h1: .xl3
    case .h2: .xl2
    case .h3: .xl
    case .h4, .lead, .large: .lg
    case .code, .small, .muted: .sm
    default: .base
    }
  }

  var weight: Font.Weight {
    switch self {
    case .h1, .h2: .bold
    case .h3, .h4, .large, .code: .semibold
    case .small: .medium
    default: .regular
    }
  }

  var color: Color {
    switch self {
    case .lead, .muted: .labelSecondary
    default: .label
    }
  }

  var isHeading: Bool {
    switch self {
    case .h1, .h2, .h3, .h4: true
    default: false
    }
  }
}

private struct TextVariantModifier: ViewModifier {
  let variant: TextVariant

  func body(content: Content) -> some View {
    switch variant {
    case .blockquote:
      styled(content)
        .italic()
        .padding(.leading, 12)
        .overlay(alignment: .leading) {
          Rectangle().fill(Color.separator).frame(width: 2)
        }
        .padding(.top, 16)
    case .code:
      styled(content)
        .monospaced()
        .padding(.horizontal, 4)
        .padding(.vertical, 2)
        .background(Color.surfaceSecondary, in: RoundedRectangle(cornerRadius: Radius.sm, style: .continuous))
    case .p:
      styled(content).padding(.top, 12)
    default:
      styled(content)
    }
  }

  private func styled(_ content: Content) -> some View {
    content
      .scaledTextStyle(variant.style, weight: variant.weight)
      .foregroundStyle(variant.color)
      .accessibilityAddTraits(variant.isHeading ? .isHeader : [])
  }
}

extension View {
  public func textVariant(_ variant: TextVariant) -> some View {
    modifier(TextVariantModifier(variant: variant))
  }
}

private struct ScaledTextStyleModifier: ViewModifier {
  let style: TextStyle
  let weight: Font.Weight

  @ScaledMetric(relativeTo: .body) private var scale: CGFloat = 1

  func body(content: Content) -> some View {
    let size = style.size * scale
    let lineSpacing = max(0, style.lineHeight * scale - UIFont.systemFont(ofSize: size).lineHeight)
    content
      .font(.system(size: size, weight: weight))
      .tracking(style.letterSpacing)
      .lineSpacing(lineSpacing)
      .padding(.vertical, lineSpacing / 2)
  }
}

extension View {
  func scaledTextStyle(_ style: TextStyle, weight: Font.Weight = .regular) -> some View {
    modifier(ScaledTextStyleModifier(style: style, weight: weight))
  }

  func scaledFont(_ style: TextStyle, weight: Font.Weight = .regular) -> some View {
    modifier(ScaledFontModifier(style: style, weight: weight))
  }
}

private struct ScaledFontModifier: ViewModifier {
  let style: TextStyle
  let weight: Font.Weight

  @ScaledMetric(relativeTo: .body) private var scale: CGFloat = 1

  func body(content: Content) -> some View {
    content
      .font(.system(size: style.size * scale, weight: weight))
      .tracking(style.letterSpacing)
  }
}
```

5. Add the files to your app target.

**Jetpack Compose**

1. Set `minSdk` to 24 or higher and add the dependencies:

```kotlin title="build.gradle.kts"
implementation(platform("androidx.compose:compose-bom:2026.09.00"))
implementation("androidx.compose.foundation:foundation")
implementation("androidx.compose.ui:ui")
implementation("com.adamglin:phosphor-icon-android:1.0.0")
```

2. Copy the theme files every view uses:

```kt title="kotlin/theme/Theme.kt"
package com.esuiss.ui.theme

import androidx.compose.foundation.isSystemInDarkTheme
import androidx.compose.runtime.Composable
import androidx.compose.runtime.CompositionLocalProvider
import androidx.compose.runtime.Immutable
import androidx.compose.runtime.staticCompositionLocalOf
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.dropShadow
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.Shape
import androidx.compose.ui.graphics.shadow.Shadow as DropShadow
import androidx.compose.ui.text.TextStyle
import androidx.compose.ui.text.style.LineHeightStyle
import androidx.compose.ui.unit.Dp
import androidx.compose.ui.unit.DpOffset
import androidx.compose.ui.unit.em
import androidx.compose.ui.unit.sp

internal fun textStyle(size: Double, lineHeight: Double, letterSpacing: Double) = TextStyle(
    fontSize = size.sp,
    lineHeight = lineHeight.sp,
    letterSpacing = letterSpacing.em,
    lineHeightStyle = LineHeightStyle(
        alignment = LineHeightStyle.Alignment.Center,
        trim = LineHeightStyle.Trim.None,
    ),
)

@Immutable
data class Shadow(
    val offsetX: Dp,
    val offsetY: Dp,
    val blur: Dp,
    val color: Color,
)

fun Modifier.shadow(shadow: Shadow, shape: Shape): Modifier = dropShadow(
    shape,
    DropShadow(
        radius = shadow.blur,
        color = shadow.color,
        offset = DpOffset(shadow.offsetX, shadow.offsetY),
    ),
)

val LocalColors = staticCompositionLocalOf { LightColors }

object EsuissTheme {
    val colors: Colors
        @Composable get() = LocalColors.current

    val typography: Typography
        get() = Typography

    val radius: Radius
        get() = Radius

    val shadows: Shadows
        get() = Shadows
}

@Composable
fun EsuissTheme(
    darkTheme: Boolean = isSystemInDarkTheme(),
    content: @Composable () -> Unit,
) {
    CompositionLocalProvider(
        LocalColors provides if (darkTheme) DarkColors else LightColors,
        content = content,
    )
}
```

```kt title="kotlin/theme/Tokens.kt"
package com.esuiss.ui.theme

import androidx.compose.runtime.Immutable
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.unit.dp

@Immutable
data class Colors(
    val surface: Color,
    val surfaceSecondary: Color,
    val surfaceTertiary: Color,
    val surfaceRaised: Color,
    val label: Color,
    val labelSecondary: Color,
    val labelTertiary: Color,
    val labelQuaternary: Color,
    val control: Color,
    val controlPressed: Color,
    val controlSelected: Color,
    val controlDisabled: Color,
    val onControlSelected: Color,
    val itemPressed: Color,
    val itemSelected: Color,
    val separator: Color,
    val separatorStrong: Color,
    val accent: Color,
    val accentPressed: Color,
    val accentSelected: Color,
    val accentDisabled: Color,
    val onAccent: Color,
    val accentSurface: Color,
    val accentSurfacePressed: Color,
    val link: Color,
    val focus: Color,
    val scrim: Color,
    val media: Color,
    val onMedia: Color,
    val danger: Color,
    val dangerSurface: Color,
    val dangerSurfacePressed: Color,
    val success: Color,
    val successSurface: Color,
    val warning: Color,
    val warningSurface: Color,
    val blue: Color,
    val green: Color,
    val orange: Color,
    val red: Color,
    val yellow: Color,
    val purple: Color,
    val pink: Color,
    val indigo: Color,
    val teal: Color,
    val mint: Color,
    val cyan: Color,
    val brown: Color,
    val gray: Color,
    val isDark: Boolean,
)

val LightColors = Colors(
    surface = Color(0xFFFFFFFF),
    surfaceSecondary = Color(0xFFF5F5F7),
    surfaceTertiary = Color(0xFFE8E8ED),
    surfaceRaised = Color(0xFFFFFFFF),
    label = Color(0xFF1D1D1F),
    labelSecondary = Color(0xFF6E6E73),
    labelTertiary = Color(0xFF86868B),
    labelQuaternary = Color(0xFFD2D2D7),
    control = Color(0xFF000000).copy(alpha = 0.04f),
    controlPressed = Color(0xFF000000).copy(alpha = 0.12f),
    controlSelected = Color(0xFF1D1D1F),
    controlDisabled = Color(0xFF000000).copy(alpha = 0.03f),
    onControlSelected = Color(0xFFFFFFFF),
    itemPressed = Color(0xFF000000).copy(alpha = 0.08f),
    itemSelected = Color(0xFF000000).copy(alpha = 0.06f),
    separator = Color(0xFFD2D2D7),
    separatorStrong = Color(0xFF86868B),
    accent = Color(0xFF0071E3),
    accentPressed = Color(0xFF005BB8),
    accentSelected = Color(0xFF0071E3),
    accentDisabled = Color(0xFF0071E3).copy(alpha = 0.4f),
    onAccent = Color(0xFFFFFFFF),
    accentSurface = Color(0xFF0071E3).copy(alpha = 0.09f),
    accentSurfacePressed = Color(0xFF0071E3).copy(alpha = 0.18f),
    link = Color(0xFF0066CC),
    focus = Color(0xFF0071E3),
    scrim = Color(0xFF000000).copy(alpha = 0.48f),
    media = Color(0xFF000000),
    onMedia = Color(0xFFFFFFFF),
    danger = Color(0xFFD0000A),
    dangerSurface = Color(0xFFD70015).copy(alpha = 0.08f),
    dangerSurfacePressed = Color(0xFFD70015).copy(alpha = 0.16f),
    success = Color(0xFF008009),
    successSurface = Color(0xFFEFFAF1),
    warning = Color(0xFFB64400),
    warningSurface = Color(0xFFFFF5EA),
    blue = Color(0xFF007AFF),
    green = Color(0xFF34C759),
    orange = Color(0xFFFF9500),
    red = Color(0xFFFF3B30),
    yellow = Color(0xFFFFCC00),
    purple = Color(0xFFAF52DE),
    pink = Color(0xFFFF2D55),
    indigo = Color(0xFF5856D6),
    teal = Color(0xFF30B0C7),
    mint = Color(0xFF00C7BE),
    cyan = Color(0xFF32ADE6),
    brown = Color(0xFFA2845E),
    gray = Color(0xFF8E8E93),
    isDark = false,
)

val DarkColors = Colors(
    surface = Color(0xFF000000),
    surfaceSecondary = Color(0xFF161617),
    surfaceTertiary = Color(0xFF2C2C2E),
    surfaceRaised = Color(0xFF1D1D1F),
    label = Color(0xFFF5F5F7),
    labelSecondary = Color(0xFFA1A1A6),
    labelTertiary = Color(0xFF86868B),
    labelQuaternary = Color(0xFF424245),
    control = Color(0xFFFFFFFF).copy(alpha = 0.1f),
    controlPressed = Color(0xFFFFFFFF).copy(alpha = 0.22f),
    controlSelected = Color(0xFFF5F5F7),
    controlDisabled = Color(0xFFFFFFFF).copy(alpha = 0.05f),
    onControlSelected = Color(0xFF000000),
    itemPressed = Color(0xFFFFFFFF).copy(alpha = 0.12f),
    itemSelected = Color(0xFFFFFFFF).copy(alpha = 0.1f),
    separator = Color(0xFF424245),
    separatorStrong = Color(0xFF6E6E73),
    accent = Color(0xFF0071E3),
    accentPressed = Color(0xFF004D9E),
    accentSelected = Color(0xFF0071E3),
    accentDisabled = Color(0xFF0071E3).copy(alpha = 0.4f),
    onAccent = Color(0xFFFFFFFF),
    accentSurface = Color(0xFF0071E3).copy(alpha = 0.18f),
    accentSurfacePressed = Color(0xFF0071E3).copy(alpha = 0.3f),
    link = Color(0xFF2997FF),
    focus = Color(0xFF0071E3),
    scrim = Color(0xFF000000).copy(alpha = 0.48f),
    media = Color(0xFF000000),
    onMedia = Color(0xFFFFFFFF),
    danger = Color(0xFFFF5447),
    dangerSurface = Color(0xFFFF453A).copy(alpha = 0.2f),
    dangerSurfacePressed = Color(0xFFFF453A).copy(alpha = 0.36f),
    success = Color(0xFF30D158),
    successSurface = Color(0xFF30D158).copy(alpha = 0.16f),
    warning = Color(0xFFFF9F0A),
    warningSurface = Color(0xFFFF9F0A).copy(alpha = 0.16f),
    blue = Color(0xFF0A84FF),
    green = Color(0xFF30D158),
    orange = Color(0xFFFF9F0A),
    red = Color(0xFFFF453A),
    yellow = Color(0xFFFFD60A),
    purple = Color(0xFFBF5AF2),
    pink = Color(0xFFFF375F),
    indigo = Color(0xFF5E5CE6),
    teal = Color(0xFF40C8E0),
    mint = Color(0xFF66D4CF),
    cyan = Color(0xFF64D2FF),
    brown = Color(0xFFAC8E68),
    gray = Color(0xFF8E8E93),
    isDark = true,
)

object Radius {
    val xs = 3.dp
    val sm = 5.dp
    val md = 8.dp
    val lg = 10.dp
    val xl = 12.dp
    val xl2 = 18.dp
    val xl3 = 28.dp
    val full = 9999.dp
}

object Typography {
    val xs3 = textStyle(11.0, 13.0, 0.006)
    val xs2 = textStyle(12.0, 16.0, 0.0)
    val xs = textStyle(13.0, 18.0, -0.006)
    val sm = textStyle(15.0, 20.0, -0.016)
    val md = textStyle(16.0, 21.0, -0.02)
    val base = textStyle(17.0, 22.0, -0.026)
    val lg = textStyle(20.0, 25.0, -0.023)
    val xl = textStyle(22.0, 28.0, -0.012)
    val xl2 = textStyle(28.0, 34.0, 0.014)
    val xl3 = textStyle(34.0, 41.0, 0.012)

    val all = listOf(xs3, xs2, xs, sm, md, base, lg, xl, xl2, xl3)
}

object Shadows {
    val md = Shadow(2.dp, 4.dp, 12.dp, Color.Black.copy(alpha = 0.08f))
    val lg = Shadow(0.dp, 4.dp, 24.dp, Color.Black.copy(alpha = 0.12f))
}
```

3. Copy the source and every file it uses:

```kt title="kotlin/components/PageIndicator.kt"
package com.esuiss.ui.components

import androidx.compose.animation.animateColorAsState
import androidx.compose.animation.core.animateDpAsState
import androidx.compose.animation.core.animateFloatAsState
import androidx.compose.animation.core.tween
import androidx.compose.foundation.background
import androidx.compose.foundation.clickable
import androidx.compose.foundation.interaction.MutableInteractionSource
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.height
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.layout.width
import androidx.compose.foundation.shape.CircleShape
import androidx.compose.runtime.Composable
import androidx.compose.runtime.getValue
import androidx.compose.runtime.key
import androidx.compose.runtime.remember
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.clip
import androidx.compose.ui.graphics.graphicsLayer
import androidx.compose.ui.semantics.Role
import androidx.compose.ui.semantics.clearAndSetSemantics
import androidx.compose.ui.semantics.contentDescription
import androidx.compose.ui.semantics.selected
import androidx.compose.ui.semantics.semantics
import androidx.compose.ui.semantics.stateDescription
import androidx.compose.ui.unit.Dp
import androidx.compose.ui.unit.dp
import com.esuiss.ui.theme.EsuissTheme

enum class PageIndicatorSize(val dot: Dp, val active: Dp, val gap: Dp) {
    Sm(6.dp, 14.dp, 6.dp),
    Default(8.dp, 20.dp, 8.dp),
}

enum class PageIndicatorVariant { Default, Accent }

@Composable
fun PageIndicator(
    count: Int,
    index: Int,
    modifier: Modifier = Modifier,
    onIndexChange: ((Int) -> Unit)? = null,
    size: PageIndicatorSize = PageIndicatorSize.Default,
    variant: PageIndicatorVariant = PageIndicatorVariant.Default,
    maxVisible: Int = 7,
    accessibilityLabel: String? = null,
) {
    if (count <= 0) return
    val colors = EsuissTheme.colors
    val haptics = rememberHaptics()
    val current = index.coerceIn(0, count - 1)
    val visible = maxVisible.coerceAtLeast(5)
    val start = if (count <= visible) 0 else (current - visible / 2).coerceIn(0, count - visible)
    val end = if (count <= visible) count else start + visible
    val activeColor = if (variant == PageIndicatorVariant.Accent) colors.accent else colors.label
    val summary = "Page ${current + 1} of $count"
    Row(
        modifier = modifier
            .height(24.dp)
            .then(
                if (onIndexChange == null) {
                    Modifier.clearAndSetSemantics {
                        contentDescription = accessibilityLabel ?: summary
                        if (accessibilityLabel != null) stateDescription = summary
                    }
                } else {
                    Modifier.semantics {
                        if (accessibilityLabel != null) contentDescription = accessibilityLabel
                        stateDescription = summary
                    }
                },
            ),
        verticalAlignment = Alignment.CenterVertically,
    ) {
        for (page in start until end) {
            key(page) {
                val position = page - start
                val edge = when {
                    start > 0 && position == 0 -> 0.5f
                    start > 0 && position == 1 -> 0.75f
                    end < count && position == visible - 1 -> 0.5f
                    end < count && position == visible - 2 -> 0.75f
                    else -> 1f
                }
                val active = page == current
                val scale by animateFloatAsState(edge, tween(250), label = "scale")
                val width by animateDpAsState(if (active) size.active else size.dot, tween(300, easing = CarouselEasing), label = "width")
                val color by animateColorAsState(if (active) activeColor else colors.labelQuaternary, tween(300), label = "color")
                Box(
                    modifier = Modifier
                        .height(24.dp)
                        .then(
                            if (onIndexChange != null) {
                                Modifier
                                    .clickable(
                                        interactionSource = remember { MutableInteractionSource() },
                                        indication = null,
                                        role = Role.Button,
                                    ) {
                                        if (page != current) haptics.selection()
                                        onIndexChange(page)
                                    }
                                    .semantics {
                                        contentDescription = "Page ${page + 1}"
                                        selected = active
                                    }
                            } else {
                                Modifier
                            },
                        )
                        .padding(horizontal = size.gap / 2),
                    contentAlignment = Alignment.Center,
                ) {
                    Box(
                        modifier = Modifier
                            .graphicsLayer {
                                scaleX = scale
                                scaleY = scale
                            }
                            .width(width)
                            .height(size.dot)
                            .clip(CircleShape)
                            .background(color, CircleShape),
                    )
                }
            }
        }
    }
}
```

```kt title="kotlin/components/Button.kt"
package com.esuiss.ui.components

import androidx.compose.foundation.background
import androidx.compose.foundation.border
import androidx.compose.foundation.clickable
import androidx.compose.foundation.interaction.MutableInteractionSource
import androidx.compose.foundation.interaction.collectIsPressedAsState
import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.RowScope
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.height
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.layout.size
import androidx.compose.foundation.shape.CircleShape
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.foundation.text.BasicText
import androidx.compose.runtime.Composable
import androidx.compose.runtime.CompositionLocalProvider
import androidx.compose.runtime.getValue
import androidx.compose.runtime.remember
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.clip
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.semantics.Role
import androidx.compose.ui.text.TextStyle
import androidx.compose.ui.text.style.TextDecoration
import androidx.compose.ui.unit.Dp
import androidx.compose.ui.unit.dp
import com.esuiss.ui.theme.Colors
import com.esuiss.ui.theme.EsuissTheme
import com.esuiss.ui.theme.Radius
import com.esuiss.ui.theme.Typography

enum class ButtonVariant { Default, Outline, Secondary, Tinted, Ghost, Plain, Destructive, Link }

enum class ButtonSize(
    val height: Dp,
    val horizontalPadding: Dp,
    val spacing: Dp,
    val iconSize: Dp,
    val blockRadius: Dp,
    val isIcon: Boolean,
) {
    Default(36.dp, 16.dp, 6.dp, 16.dp, Radius.md, false),
    Xs(24.dp, 11.dp, 4.dp, 12.dp, Radius.sm, false),
    Sm(32.dp, 12.dp, 4.dp, 16.dp, Radius.md, false),
    Lg(44.dp, 22.dp, 6.dp, 16.dp, Radius.lg, false),
    Xl(56.dp, 31.dp, 8.dp, 16.dp, Radius.xl, false),
    Icon(36.dp, 0.dp, 6.dp, 16.dp, Radius.md, true),
    IconXs(24.dp, 0.dp, 4.dp, 12.dp, Radius.sm, true),
    IconSm(32.dp, 0.dp, 4.dp, 16.dp, Radius.md, true),
    IconLg(44.dp, 0.dp, 6.dp, 16.dp, Radius.lg, true),
    IconXl(56.dp, 0.dp, 8.dp, 16.dp, Radius.xl, true),
    ;

    val textStyle: TextStyle
        get() = when (this) {
            Xs, IconXs -> Typography.xs2
            Lg, Xl -> Typography.base
            else -> Typography.sm
        }
}

@Composable
fun Button(
    onClick: () -> Unit,
    modifier: Modifier = Modifier,
    variant: ButtonVariant = ButtonVariant.Default,
    size: ButtonSize = ButtonSize.Default,
    block: Boolean = false,
    enabled: Boolean = true,
    content: @Composable RowScope.() -> Unit,
) {
    val colors = EsuissTheme.colors
    val interaction = remember { MutableInteractionSource() }
    val pressed by interaction.collectIsPressedAsState()
    val foreground = buttonForeground(variant, colors, enabled)
    val group = LocalButtonGroup.current?.takeIf { variant != ButtonVariant.Ghost && variant != ButtonVariant.Plain }
    RegisterButtonGroupOutline(group, variant == ButtonVariant.Outline)
    val shape = group.itemShape(if (block) RoundedCornerShape(size.blockRadius) else CircleShape)
    val sizing = when {
        block -> Modifier.fillMaxWidth().height(size.height)
        size.isIcon -> Modifier.size(size.height)
        else -> Modifier.height(size.height)
    }

    Row(
        modifier = modifier
            .then(sizing)
            .clip(shape)
            .background(buttonBackground(variant, colors, pressed && enabled, enabled), shape)
            .then(
                when {
                    variant != ButtonVariant.Outline -> Modifier
                    group != null -> Modifier.buttonGroupEdge(group, colors.separator)
                    else -> Modifier.border(1.dp, colors.separator, shape)
                },
            )
            .clickable(
                interactionSource = interaction,
                indication = null,
                enabled = enabled,
                role = Role.Button,
                onClick = onClick,
            )
            .padding(horizontal = size.horizontalPadding),
        horizontalArrangement = Arrangement.spacedBy(size.spacing, Alignment.CenterHorizontally),
        verticalAlignment = Alignment.CenterVertically,
    ) {
        CompositionLocalProvider(
            LocalButtonGroup provides null,
            LocalContentStyle provides size.textStyle.copy(
                color = foreground,
                textDecoration = if (variant == ButtonVariant.Link && pressed && enabled) {
                    TextDecoration.Underline
                } else {
                    null
                },
            ),
            LocalContentColor provides foreground,
            LocalIconSize provides size.iconSize,
        ) {
            content()
        }
    }
}

@Composable
fun Button(
    text: String,
    onClick: () -> Unit,
    modifier: Modifier = Modifier,
    variant: ButtonVariant = ButtonVariant.Default,
    size: ButtonSize = ButtonSize.Default,
    block: Boolean = false,
    enabled: Boolean = true,
) {
    Button(onClick, modifier, variant, size, block, enabled) {
        BasicText(text, style = LocalContentStyle.current, maxLines = 1)
    }
}

private fun buttonForeground(variant: ButtonVariant, colors: Colors, enabled: Boolean): Color =
    when (variant) {
        ButtonVariant.Default -> colors.onAccent
        ButtonVariant.Outline, ButtonVariant.Secondary, ButtonVariant.Ghost ->
            if (enabled) colors.label else colors.labelQuaternary
        ButtonVariant.Tinted, ButtonVariant.Plain ->
            if (enabled) colors.link else colors.link.copy(alpha = 0.4f)
        ButtonVariant.Destructive ->
            if (enabled) colors.danger else colors.danger.copy(alpha = 0.4f)
        ButtonVariant.Link -> if (enabled) colors.link else colors.labelQuaternary
    }

private fun buttonBackground(variant: ButtonVariant, colors: Colors, pressed: Boolean, enabled: Boolean): Color =
    when (variant) {
        ButtonVariant.Default -> when {
            !enabled -> colors.accentDisabled
            pressed -> colors.accentPressed
            else -> colors.accent
        }
        ButtonVariant.Outline -> when {
            pressed -> colors.itemPressed
            colors.isDark -> Color.Transparent
            else -> colors.surface
        }
        ButtonVariant.Secondary -> when {
            !enabled -> colors.controlDisabled
            pressed -> colors.controlPressed
            else -> colors.control
        }
        ButtonVariant.Tinted -> if (pressed) colors.accentSurfacePressed else colors.accentSurface
        ButtonVariant.Ghost -> if (pressed) colors.itemPressed else Color.Transparent
        ButtonVariant.Plain -> if (pressed) colors.itemPressed else Color.Transparent
        ButtonVariant.Destructive -> if (pressed) colors.dangerSurfacePressed else colors.dangerSurface
        ButtonVariant.Link -> Color.Transparent
    }
```

```kt title="kotlin/components/ButtonGroup.kt"
package com.esuiss.ui.components

import androidx.compose.foundation.background
import androidx.compose.foundation.gestures.Orientation
import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.RowScope
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.shape.CircleShape
import androidx.compose.foundation.shape.CornerSize
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.runtime.Composable
import androidx.compose.runtime.CompositionLocalProvider
import androidx.compose.runtime.DisposableEffect
import androidx.compose.runtime.Immutable
import androidx.compose.runtime.Stable
import androidx.compose.runtime.compositionLocalOf
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableIntStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.setValue
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.clip
import androidx.compose.ui.draw.drawBehind
import androidx.compose.ui.draw.drawWithContent
import androidx.compose.ui.geometry.Offset
import androidx.compose.ui.geometry.Size
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.RectangleShape
import androidx.compose.ui.graphics.Shape
import androidx.compose.ui.graphics.drawOutline
import androidx.compose.ui.graphics.drawscope.Stroke
import androidx.compose.ui.graphics.drawscope.translate
import androidx.compose.ui.graphics.takeOrElse
import androidx.compose.ui.layout.Layout
import androidx.compose.ui.layout.Placeable
import androidx.compose.ui.layout.layout
import androidx.compose.ui.layout.layoutId
import androidx.compose.ui.layout.onPlaced
import androidx.compose.ui.platform.LocalLayoutDirection
import androidx.compose.ui.semantics.isTraversalGroup
import androidx.compose.ui.semantics.semantics
import androidx.compose.ui.unit.Constraints
import androidx.compose.ui.unit.LayoutDirection
import androidx.compose.ui.unit.constrainHeight
import androidx.compose.ui.unit.constrainWidth
import androidx.compose.ui.unit.dp
import com.esuiss.ui.theme.EsuissTheme
import com.esuiss.ui.theme.Radius
import com.esuiss.ui.theme.Typography

enum class ButtonGroupOrientation { Horizontal, Vertical }

@Stable
internal class ButtonGroupState(val orientation: ButtonGroupOrientation) {
    var nested by mutableIntStateOf(0)
    var outlined by mutableIntStateOf(0)
}

internal val LocalButtonGroup = compositionLocalOf<ButtonGroupState?> { null }

internal object ButtonGroupFill

private object ButtonGroupDivider

internal fun ButtonGroupState?.itemShape(default: Shape): Shape = if (this == null) default else RectangleShape

@Immutable
internal class ButtonGroupItem(val shape: Shape, val modifier: Modifier)

@Composable
internal fun rememberButtonGroupItem(group: ButtonGroupState?, default: Shape): ButtonGroupItem {
    var edges by remember { mutableIntStateOf(0) }
    val horizontal = group?.orientation != ButtonGroupOrientation.Vertical
    val rtl = LocalLayoutDirection.current == LayoutDirection.Rtl
    val shape = remember(edges, horizontal) {
        val round = if (horizontal) CornerSize(50) else CornerSize(Radius.xl2)
        val square = CornerSize(0)
        val start = if (edges and 1 != 0) round else square
        val end = if (edges and 2 != 0) round else square
        if (horizontal) {
            RoundedCornerShape(topStart = start, topEnd = end, bottomEnd = end, bottomStart = start)
        } else {
            RoundedCornerShape(topStart = start, topEnd = start, bottomEnd = end, bottomStart = end)
        }
    }
    if (group == null || group.nested > 0) return ButtonGroupItem(default, Modifier)
    return ButtonGroupItem(
        shape = shape,
        modifier = Modifier.onPlaced { coordinates ->
            val parent = coordinates.parentLayoutCoordinates ?: return@onPlaced
            val bounds = parent.localBoundingBoxOf(coordinates, clipBounds = false)
            val first: Boolean
            val last: Boolean
            if (horizontal) {
                val left = bounds.left <= 0.5f
                val right = bounds.right >= parent.size.width - 0.5f
                first = if (rtl) right else left
                last = if (rtl) left else right
            } else {
                first = bounds.top <= 0.5f
                last = bounds.bottom >= parent.size.height - 0.5f
            }
            edges = (if (first) 1 else 0) or (if (last) 2 else 0)
        },
    )
}

internal fun Modifier.buttonGroupEdge(group: ButtonGroupState?, color: Color): Modifier {
    if (group == null) return this
    return drawBehind {
        val stroke = 1.dp.toPx()
        if (group.orientation == ButtonGroupOrientation.Horizontal) {
            val x = if (layoutDirection == LayoutDirection.Rtl) 0f else size.width - stroke
            drawRect(color, Offset(x, 0f), Size(stroke, size.height))
        } else {
            drawRect(color, Offset(0f, size.height - stroke), Size(size.width, stroke))
        }
    }
}

@Composable
internal fun RegisterButtonGroupOutline(group: ButtonGroupState?, outlined: Boolean) {
    DisposableEffect(group, outlined) {
        if (group != null && outlined) group.outlined += 1
        onDispose {
            if (group != null && outlined) group.outlined -= 1
        }
    }
}

@Composable
fun ButtonGroup(
    modifier: Modifier = Modifier,
    orientation: ButtonGroupOrientation = ButtonGroupOrientation.Horizontal,
    content: @Composable () -> Unit,
) {
    val parent = LocalButtonGroup.current
    DisposableEffect(parent) {
        parent?.let { it.nested += 1 }
        onDispose { parent?.let { it.nested -= 1 } }
    }
    val state = remember(orientation) { ButtonGroupState(orientation) }
    val colors = EsuissTheme.colors
    val joined = state.nested == 0
    val horizontal = orientation == ButtonGroupOrientation.Horizontal
    val shape = if (horizontal) CircleShape else RoundedCornerShape(Radius.xl2)
    val outline = colors.separator
    Layout(
        content = {
            CompositionLocalProvider(LocalButtonGroup provides state, content = content)
        },
        modifier = modifier
            .semantics { isTraversalGroup = true }
            .then(
                if (joined) {
                    Modifier
                        .clip(shape)
                        .drawWithContent {
                            drawContent()
                            if (state.outlined > 0) {
                                val stroke = 1.dp.toPx()
                                val inset = stroke / 2
                                val path = shape.createOutline(
                                    Size(size.width - stroke, size.height - stroke),
                                    layoutDirection,
                                    this,
                                )
                                translate(inset, inset) {
                                    drawOutline(path, outline, style = Stroke(stroke))
                                }
                            }
                        }
                } else {
                    Modifier
                },
            ),
    ) { measurables, constraints ->
        val gap = if (joined) 0 else 8.dp.roundToPx()
        val items = measurables.filter { it.layoutId != ButtonGroupDivider }
        if (horizontal) {
            val height = if (constraints.hasFixedHeight) {
                constraints.maxHeight
            } else {
                constraints.constrainHeight(items.maxOfOrNull { it.maxIntrinsicHeight(Constraints.Infinity) } ?: 0)
            }
            val fills = measurables.count { it.layoutId == ButtonGroupFill }
            val placeables = arrayOfNulls<Placeable>(measurables.size)
            var used = 0
            measurables.forEachIndexed { index, measurable ->
                if (measurable.layoutId != ButtonGroupFill) {
                    val placeable = measurable.measure(Constraints(minHeight = height, maxHeight = height))
                    placeables[index] = placeable
                    used += placeable.width
                }
            }
            val gaps = gap * (items.size - 1).coerceAtLeast(0)
            val remaining = if (constraints.hasBoundedWidth) {
                (constraints.maxWidth - used - gaps).coerceAtLeast(0)
            } else {
                0
            }
            measurables.forEachIndexed { index, measurable ->
                if (measurable.layoutId == ButtonGroupFill) {
                    val placeable = if (constraints.hasBoundedWidth) {
                        val width = remaining / fills
                        measurable.measure(Constraints(width, width, height, height))
                    } else {
                        measurable.measure(Constraints(minHeight = height, maxHeight = height))
                    }
                    placeables[index] = placeable
                    used += placeable.width
                }
            }
            val width = constraints.constrainWidth(used + gaps)
            layout(width, height) {
                var x = 0
                measurables.forEachIndexed { index, measurable ->
                    val placeable = placeables[index] ?: return@forEachIndexed
                    val divider = measurable.layoutId == ButtonGroupDivider
                    placeable.placeRelative(x, 0, zIndex = if (divider) 1f else 0f)
                    if (!divider) x += placeable.width + gap
                }
            }
        } else {
            val width = if (constraints.hasFixedWidth) {
                constraints.maxWidth
            } else {
                constraints.constrainWidth(items.maxOfOrNull { it.maxIntrinsicWidth(Constraints.Infinity) } ?: 0)
            }
            val placeables = measurables.map { it.measure(Constraints(minWidth = width, maxWidth = width)) }
            val gaps = gap * (items.size - 1).coerceAtLeast(0)
            val height = constraints.constrainHeight(
                placeables.filterIndexed { index, _ -> measurables[index].layoutId != ButtonGroupDivider }.sumOf { it.height } + gaps,
            )
            layout(width, height) {
                var y = 0
                measurables.forEachIndexed { index, measurable ->
                    val divider = measurable.layoutId == ButtonGroupDivider
                    placeables[index].placeRelative(0, y, zIndex = if (divider) 1f else 0f)
                    if (!divider) y += placeables[index].height + gap
                }
            }
        }
    }
}

@Composable
fun ButtonGroupText(
    modifier: Modifier = Modifier,
    content: @Composable RowScope.() -> Unit,
) {
    val colors = EsuissTheme.colors
    val shape = LocalButtonGroup.current.itemShape(CircleShape)
    Row(
        modifier = modifier
            .clip(shape)
            .background(colors.control, shape)
            .padding(horizontal = 10.dp),
        horizontalArrangement = Arrangement.spacedBy(8.dp),
        verticalAlignment = Alignment.CenterVertically,
    ) {
        CompositionLocalProvider(
            LocalButtonGroup provides null,
            LocalContentStyle provides Typography.sm.copy(color = colors.label),
            LocalContentColor provides colors.label,
            LocalIconSize provides 16.dp,
        ) {
            content()
        }
    }
}

@Composable
fun ButtonGroupSeparator(
    modifier: Modifier = Modifier,
    orientation: Orientation = Orientation.Vertical,
    color: Color = Color.Unspecified,
) {
    val line = color.takeOrElse { EsuissTheme.colors.label.copy(alpha = 0.2f) }
    Box(
        modifier = modifier
            .layoutId(ButtonGroupDivider)
            .then(
                if (orientation == Orientation.Vertical) {
                    Modifier.layout { measurable, constraints ->
                        val placeable = measurable.measure(constraints.copy(minWidth = 0, maxWidth = 0))
                        layout(0, placeable.height) { placeable.place(0, 0) }
                    }
                } else {
                    Modifier.layout { measurable, constraints ->
                        val placeable = measurable.measure(constraints.copy(minHeight = 0, maxHeight = 0))
                        layout(placeable.width, 0) { placeable.place(0, 0) }
                    }
                },
            )
            .drawBehind {
                val stroke = 1.dp.toPx()
                val inset = 9.dp.toPx()
                if (orientation == Orientation.Vertical) {
                    val x = if (layoutDirection == LayoutDirection.Rtl) -stroke else 0f
                    drawRect(line, Offset(x, inset), Size(stroke, (size.height - inset * 2).coerceAtLeast(0f)))
                } else {
                    drawRect(line, Offset(inset, 0f), Size((size.width - inset * 2).coerceAtLeast(0f), stroke))
                }
            },
    )
}
```

```kt title="kotlin/components/Carousel.kt"
package com.esuiss.ui.components

import androidx.compose.animation.animateColorAsState
import androidx.compose.animation.core.Animatable
import androidx.compose.animation.core.CubicBezierEasing
import androidx.compose.animation.core.LinearEasing
import androidx.compose.animation.core.animateDpAsState
import androidx.compose.animation.core.tween
import androidx.compose.foundation.background
import androidx.compose.foundation.clickable
import androidx.compose.foundation.interaction.MutableInteractionSource
import androidx.compose.foundation.interaction.collectIsDraggedAsState
import androidx.compose.foundation.interaction.collectIsPressedAsState
import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.BoxScope
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.ColumnScope
import androidx.compose.foundation.layout.PaddingValues
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.RowScope
import androidx.compose.foundation.layout.fillMaxHeight
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.height
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.layout.width
import androidx.compose.foundation.pager.HorizontalPager
import androidx.compose.foundation.pager.PagerState
import androidx.compose.foundation.pager.VerticalPager
import androidx.compose.foundation.pager.rememberPagerState
import androidx.compose.foundation.shape.CircleShape
import androidx.compose.runtime.Composable
import androidx.compose.runtime.CompositionLocalProvider
import androidx.compose.runtime.LaunchedEffect
import androidx.compose.runtime.Stable
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.rememberCoroutineScope
import androidx.compose.runtime.rememberUpdatedState
import androidx.compose.runtime.setValue
import androidx.compose.runtime.snapshotFlow
import androidx.compose.runtime.staticCompositionLocalOf
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.clip
import androidx.compose.ui.draw.drawBehind
import androidx.compose.ui.geometry.CornerRadius
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.semantics.Role
import androidx.compose.ui.semantics.contentDescription
import androidx.compose.ui.semantics.selected
import androidx.compose.ui.semantics.semantics
import androidx.compose.ui.unit.Dp
import androidx.compose.ui.unit.dp
import com.adamglin.PhosphorIcons
import com.adamglin.phosphoricons.Fill
import com.adamglin.phosphoricons.Regular
import com.adamglin.phosphoricons.fill.Pause
import com.adamglin.phosphoricons.fill.Play
import com.adamglin.phosphoricons.regular.CaretDown
import com.adamglin.phosphoricons.regular.CaretLeft
import com.adamglin.phosphoricons.regular.CaretRight
import com.adamglin.phosphoricons.regular.CaretUp
import com.esuiss.ui.theme.EsuissTheme
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.flow.distinctUntilChanged
import kotlinx.coroutines.flow.drop
import kotlinx.coroutines.launch

enum class CarouselOrientation { Horizontal, Vertical }

enum class CarouselDotsVariant { Default, Plain }

internal val CarouselEasing = CubicBezierEasing(0.32f, 0.72f, 0f, 1f)

@Stable
class CarouselState internal constructor(
    internal val pager: PagerState,
    private val scope: CoroutineScope,
    val loop: Boolean,
) {
    val pageCount: Int get() = pager.pageCount

    val selectedIndex: Int get() = pager.currentPage

    val canScrollPrev: Boolean get() = pageCount > 1 && (loop || selectedIndex > 0)

    val canScrollNext: Boolean get() = pageCount > 1 && (loop || selectedIndex < pageCount - 1)

    internal var autoplayEnabled by mutableStateOf(false)

    internal var playing by mutableStateOf(false)

    internal val progress = Animatable(0f)

    fun scrollTo(index: Int, animate: Boolean = true) {
        if (pageCount == 0) return
        val target = index.coerceIn(0, pageCount - 1)
        scope.launch {
            if (animate) pager.animateScrollToPage(target, animationSpec = tween(500, easing = CarouselEasing))
            else pager.scrollToPage(target)
        }
    }

    fun scrollPrev() {
        if (!canScrollPrev) return
        scrollTo(if (selectedIndex == 0) pageCount - 1 else selectedIndex - 1)
    }

    fun scrollNext() {
        if (!canScrollNext) return
        scrollTo(if (selectedIndex == pageCount - 1) 0 else selectedIndex + 1)
    }

    fun setPlaying(playing: Boolean) {
        this.playing = playing
    }

    val isPlaying: Boolean get() = autoplayEnabled && playing
}

@Composable
fun rememberCarouselState(pageCount: Int, initialPage: Int = 0, loop: Boolean = false): CarouselState {
    val pager = rememberPagerState(initialPage) { pageCount }
    val scope = rememberCoroutineScope()
    return remember(pager, scope, loop) { CarouselState(pager, scope, loop) }
}

@Stable
private class CarouselContext(val state: CarouselState, val orientation: CarouselOrientation)

private val LocalCarousel = staticCompositionLocalOf<CarouselContext?> { null }

@Composable
private fun carousel(): CarouselContext =
    checkNotNull(LocalCarousel.current) { "Carousel parts must be used within a Carousel" }

@Composable
fun Carousel(
    state: CarouselState,
    modifier: Modifier = Modifier,
    orientation: CarouselOrientation = CarouselOrientation.Horizontal,
    autoplay: Boolean = false,
    autoplayDelayMillis: Long = 5000L,
    onSelect: ((Int) -> Unit)? = null,
    content: @Composable ColumnScope.() -> Unit,
) {
    val select by rememberUpdatedState(onSelect)
    LaunchedEffect(state) {
        snapshotFlow { state.selectedIndex }.distinctUntilChanged().drop(1).collect { select?.invoke(it) }
    }
    LaunchedEffect(state, autoplay) {
        state.autoplayEnabled = autoplay
        state.playing = autoplay
    }
    val dragged by state.pager.interactionSource.collectIsDraggedAsState()
    val running = state.autoplayEnabled && state.playing && !dragged
    val selected = state.selectedIndex
    LaunchedEffect(selected) { state.progress.snapTo(0f) }
    LaunchedEffect(state, running, selected, autoplayDelayMillis) {
        if (!running) return@LaunchedEffect
        val remaining = (autoplayDelayMillis * (1f - state.progress.value)).toInt().coerceAtLeast(0)
        state.progress.animateTo(1f, tween(remaining, easing = LinearEasing))
        if (state.selectedIndex != selected) return@LaunchedEffect
        if (state.selectedIndex < state.pageCount - 1) state.scrollTo(state.selectedIndex + 1) else state.scrollTo(0)
    }
    CompositionLocalProvider(LocalCarousel provides remember(state, orientation) { CarouselContext(state, orientation) }) {
        Column(modifier = modifier, content = content)
    }
}

@Composable
fun CarouselContent(
    modifier: Modifier = Modifier,
    contentPadding: PaddingValues = PaddingValues(0.dp),
    pageSpacing: Dp = 16.dp,
    key: ((Int) -> Any)? = null,
    content: @Composable (page: Int) -> Unit,
) {
    val context = carousel()
    if (context.orientation == CarouselOrientation.Horizontal) {
        HorizontalPager(
            state = context.state.pager,
            modifier = modifier.fillMaxWidth(),
            contentPadding = contentPadding,
            pageSpacing = pageSpacing,
            key = key,
            verticalAlignment = Alignment.Top,
        ) { page -> content(page) }
    } else {
        VerticalPager(
            state = context.state.pager,
            modifier = modifier,
            contentPadding = contentPadding,
            pageSpacing = pageSpacing,
            key = key,
            horizontalAlignment = Alignment.Start,
        ) { page -> content(page) }
    }
}

@Composable
fun CarouselItem(
    modifier: Modifier = Modifier,
    content: @Composable BoxScope.() -> Unit,
) {
    Box(modifier = modifier, content = content)
}

@Composable
fun CarouselPrevious(
    modifier: Modifier = Modifier,
    variant: ButtonVariant = ButtonVariant.Secondary,
    size: ButtonSize = ButtonSize.Icon,
    contentDescription: String = "Previous slide",
) {
    val context = carousel()
    Button(
        onClick = { context.state.scrollPrev() },
        modifier = modifier,
        variant = variant,
        size = size,
        enabled = context.state.canScrollPrev,
    ) {
        Icon(
            if (context.orientation == CarouselOrientation.Horizontal) PhosphorIcons.Regular.CaretLeft else PhosphorIcons.Regular.CaretUp,
            contentDescription = contentDescription,
        )
    }
}

@Composable
fun CarouselNext(
    modifier: Modifier = Modifier,
    variant: ButtonVariant = ButtonVariant.Secondary,
    size: ButtonSize = ButtonSize.Icon,
    contentDescription: String = "Next slide",
) {
    val context = carousel()
    Button(
        onClick = { context.state.scrollNext() },
        modifier = modifier,
        variant = variant,
        size = size,
        enabled = context.state.canScrollNext,
    ) {
        Icon(
            if (context.orientation == CarouselOrientation.Horizontal) PhosphorIcons.Regular.CaretRight else PhosphorIcons.Regular.CaretDown,
            contentDescription = contentDescription,
        )
    }
}

@Composable
fun CarouselControls(
    modifier: Modifier = Modifier,
    content: @Composable RowScope.() -> Unit,
) {
    Row(
        modifier = modifier.padding(top = 24.dp),
        horizontalArrangement = Arrangement.spacedBy(12.dp),
        verticalAlignment = Alignment.CenterVertically,
        content = content,
    )
}

@Composable
fun CarouselDots(
    modifier: Modifier = Modifier,
    variant: CarouselDotsVariant = CarouselDotsVariant.Default,
) {
    val context = carousel()
    val state = context.state
    val colors = EsuissTheme.colors
    val plain = variant == CarouselDotsVariant.Plain
    Row(
        modifier = modifier
            .height(36.dp)
            .clip(CircleShape)
            .background(if (plain) Color.Transparent else colors.control, CircleShape)
            .padding(horizontal = if (plain) 0.dp else 8.dp),
        verticalAlignment = Alignment.CenterVertically,
    ) {
        for (index in 0 until state.pageCount) {
            val active = index == state.selectedIndex
            val interaction = remember { MutableInteractionSource() }
            val pressed by interaction.collectIsPressedAsState()
            val width by animateDpAsState(if (active) 24.dp else 8.dp, tween(500, easing = CarouselEasing), label = "dot")
            val target = when {
                active && !state.autoplayEnabled -> colors.label
                pressed -> colors.labelSecondary
                else -> colors.labelTertiary
            }
            val color by animateColorAsState(target, tween(500, easing = CarouselEasing), label = "dotColor")
            val fill = colors.label
            Box(
                modifier = Modifier
                    .fillMaxHeight()
                    .clickable(interactionSource = interaction, indication = null, role = Role.Button) { state.scrollTo(index) }
                    .semantics {
                        contentDescription = "Go to slide ${index + 1}"
                        selected = active
                    }
                    .padding(horizontal = 8.dp),
                contentAlignment = Alignment.Center,
            ) {
                Box(
                    modifier = Modifier
                        .width(width)
                        .height(8.dp)
                        .clip(CircleShape)
                        .background(color, CircleShape)
                        .then(
                            if (active && state.autoplayEnabled) {
                                Modifier.drawBehind {
                                    val fraction = if (state.playing) state.progress.value else 1f
                                    drawRoundRect(
                                        color = fill,
                                        size = size.copy(width = size.width * fraction),
                                        cornerRadius = CornerRadius(size.height / 2f),
                                    )
                                }
                            } else {
                                Modifier
                            },
                        ),
                )
            }
        }
    }
}

@Composable
fun CarouselPlayButton(
    modifier: Modifier = Modifier,
    variant: ButtonVariant = ButtonVariant.Secondary,
    size: ButtonSize = ButtonSize.IconSm,
) {
    val state = carousel().state
    if (!state.autoplayEnabled) return
    Button(
        onClick = { state.setPlaying(!state.playing) },
        modifier = modifier,
        variant = variant,
        size = size,
    ) {
        Icon(
            if (state.playing) PhosphorIcons.Fill.Pause else PhosphorIcons.Fill.Play,
            contentDescription = if (state.playing) "Pause slideshow" else "Play slideshow",
        )
    }
}
```

```kt title="kotlin/components/Content.kt"
package com.esuiss.ui.components

import androidx.compose.runtime.compositionLocalOf
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.text.TextStyle
import androidx.compose.ui.unit.Dp
import androidx.compose.ui.unit.dp

val LocalContentStyle = compositionLocalOf { TextStyle.Default }

val LocalContentColor = compositionLocalOf { Color.Unspecified }

val LocalIconSize = compositionLocalOf { 20.dp }
```

```kt title="kotlin/components/Haptics.kt"
package com.esuiss.ui.components

import androidx.compose.runtime.Composable
import androidx.compose.runtime.CompositionLocalProvider
import androidx.compose.runtime.remember
import androidx.compose.runtime.staticCompositionLocalOf
import androidx.compose.ui.hapticfeedback.HapticFeedback
import androidx.compose.ui.hapticfeedback.HapticFeedbackType
import androidx.compose.ui.platform.LocalHapticFeedback

val LocalHapticsEnabled = staticCompositionLocalOf { true }

@Composable
fun ProvideHaptics(enabled: Boolean, content: @Composable () -> Unit) {
    CompositionLocalProvider(LocalHapticsEnabled provides enabled, content = content)
}

internal class Haptics(private val feedback: HapticFeedback, private val enabled: Boolean) {
    fun perform(type: HapticFeedbackType) {
        if (enabled) feedback.performHapticFeedback(type)
    }

    fun toggle(on: Boolean) = perform(if (on) HapticFeedbackType.ToggleOn else HapticFeedbackType.ToggleOff)

    fun selection() = perform(HapticFeedbackType.SegmentTick)
}

@Composable
internal fun rememberHaptics(): Haptics {
    val feedback = LocalHapticFeedback.current
    val enabled = LocalHapticsEnabled.current
    return remember(feedback, enabled) { Haptics(feedback, enabled) }
}
```

```kt title="kotlin/components/Icon.kt"
package com.esuiss.ui.components

import androidx.compose.foundation.Image
import androidx.compose.foundation.layout.size
import androidx.compose.runtime.Composable
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.ColorFilter
import androidx.compose.ui.graphics.takeOrElse
import androidx.compose.ui.graphics.vector.ImageVector
import androidx.compose.ui.unit.Dp
import com.esuiss.ui.theme.EsuissTheme

@Composable
fun Icon(
    imageVector: ImageVector,
    contentDescription: String?,
    modifier: Modifier = Modifier,
    size: Dp = LocalIconSize.current,
    tint: Color = LocalContentColor.current.takeOrElse { EsuissTheme.colors.label },
) {
    Image(
        imageVector = imageVector,
        contentDescription = contentDescription,
        modifier = modifier.size(size),
        colorFilter = ColorFilter.tint(tint),
    )
}
```

4. Update the `com.esuiss.ui` package names to match your project.

## Usage

```tsx
import { PageIndicator } from "@/components/ui/page-indicator"
```

```tsx
<PageIndicator count={5} index={1} />
```

The component is controlled: pass `count` and the current `index`. Pass `onIndexChange` to make the dots pressable; without it the indicator is display-only. Pressing a dot plays a selection haptic.

The `PageIndicatorSize` and `PageIndicatorVariant` types are also exported.

## Examples

### Sizes

The `sm` and `default` sizes.

![Preview](https://uim.suiss.app/previews/components-page-indicator--sizes.light.webp)

```tsx
import { View } from "react-native"
import { PageIndicator } from "@/components/ui/page-indicator"

export function PageIndicatorSizesExample() {
  return (
    <View className="items-center gap-6">
      <PageIndicator count={5} index={1} size="sm" />
      <PageIndicator count={5} index={1} />
    </View>
  )
}
```

```swift
import EsuissUI
import SwiftUI

struct PageIndicatorSizesExample: View {
  var body: some View {
    VStack(spacing: 24) {
      PageIndicator(count: 5, index: 1, size: .sm)
      PageIndicator(count: 5, index: 1)
    }
    .frame(maxWidth: .infinity)
  }
}
```

```kotlin
import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.runtime.Composable
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.unit.dp
import com.esuiss.ui.components.PageIndicator
import com.esuiss.ui.components.PageIndicatorSize

@Composable
fun PageIndicatorCentered(spacing: Int, content: @Composable () -> Unit) {
    Column(
        modifier = Modifier.fillMaxWidth(),
        horizontalAlignment = Alignment.CenterHorizontally,
        verticalArrangement = Arrangement.spacedBy(spacing.dp),
    ) {
        content()
    }
}

@Composable
fun PageIndicatorSizes() {
    PageIndicatorCentered(24) {
        PageIndicator(count = 5, index = 1, size = PageIndicatorSize.Sm)
        PageIndicator(count = 5, index = 1)
    }
}
```

### Accent

The `accent` variant.

![Preview](https://uim.suiss.app/previews/components-page-indicator--accent.light.webp)

```tsx
import { PageIndicator } from "@/components/ui/page-indicator"

export function PageIndicatorAccentExample() {
  return (
    <PageIndicator count={5} index={1} variant="accent" />
  )
}
```

```swift
import EsuissUI
import SwiftUI

struct PageIndicatorAccentExample: View {
  var body: some View {
    PageIndicator(count: 5, index: 1, variant: .accent)
  }
}
```

```kotlin
import androidx.compose.runtime.Composable
import com.esuiss.ui.components.PageIndicator
import com.esuiss.ui.components.PageIndicatorVariant

@Composable
fun PageIndicatorAccentExample() {
    PageIndicator(count = 5, index = 1, variant = PageIndicatorVariant.Accent)
}
```

### Many pages

Twelve pages shown in a sliding window at the start, middle and end.

![Preview](https://uim.suiss.app/previews/components-page-indicator--many-pages.light.webp)

```tsx
import { View } from "react-native"
import { PageIndicator } from "@/components/ui/page-indicator"

export function PageIndicatorManyPagesExample() {
  return (
    <View className="items-center gap-6">
      <PageIndicator count={12} index={0} />
      <PageIndicator count={12} index={5} />
      <PageIndicator count={12} index={11} />
    </View>
  )
}
```

```swift
import EsuissUI
import SwiftUI

struct PageIndicatorManyPagesExample: View {
  var body: some View {
    VStack(spacing: 24) {
      PageIndicator(count: 12, index: 0)
      PageIndicator(count: 12, index: 5)
      PageIndicator(count: 12, index: 11)
    }
    .frame(maxWidth: .infinity)
  }
}
```

```kotlin
import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.runtime.Composable
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.unit.dp
import com.esuiss.ui.components.PageIndicator

@Composable
fun PageIndicatorCentered(spacing: Int, content: @Composable () -> Unit) {
    Column(
        modifier = Modifier.fillMaxWidth(),
        horizontalAlignment = Alignment.CenterHorizontally,
        verticalArrangement = Arrangement.spacedBy(spacing.dp),
    ) {
        content()
    }
}

@Composable
fun PageIndicatorManyPages() {
    PageIndicatorCentered(24) {
        PageIndicator(count = 12, index = 0)
        PageIndicator(count = 12, index = 5)
        PageIndicator(count = 12, index = 11)
    }
}
```

### Interactive

Pressable dots that change the page through `onIndexChange`.

![Preview](https://uim.suiss.app/previews/components-page-indicator--interactive.light.webp)

```tsx
import * as React from "react"
import { View } from "react-native"
import { PageIndicator } from "@/components/ui/page-indicator"
import { Text } from "@/components/ui/text"

function InteractiveIndicator({ count }: { count: number }) {
  const [index, setIndex] = React.useState(0)
  return (
    <View className="items-center gap-3">
      <PageIndicator count={count} index={index} onIndexChange={setIndex} />
      <Text variant="muted">
        Page {index + 1} of {count}
      </Text>
    </View>
  )
}

export function PageIndicatorInteractiveExample() {
  return (
    <InteractiveIndicator count={12} />
  )
}
```

```swift
import EsuissUI
import SwiftUI

struct PageIndicatorInteractiveExample: View {
  var body: some View {
    PageIndicatorInteractive(count: 12)
  }
}

struct PageIndicatorInteractive: View {
  let count: Int

  @State private var index = 0

  var body: some View {
    VStack(spacing: 12) {
      PageIndicator(count: count, index: index) { index = $0 }
      Text(verbatim: "Page \(index + 1) of \(count)")
        .textVariant(.muted)
    }
    .frame(maxWidth: .infinity)
  }
}
```

```kotlin
import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.runtime.Composable
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableIntStateOf
import androidx.compose.runtime.saveable.rememberSaveable
import androidx.compose.runtime.setValue
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.unit.dp
import com.esuiss.ui.components.PageIndicator
import com.esuiss.ui.components.Text
import com.esuiss.ui.components.TextVariant

@Composable
fun PageIndicatorInteractiveExample() {
    PageIndicatorInteractive(12)
}

@Composable
fun PageIndicatorCentered(spacing: Int, content: @Composable () -> Unit) {
    Column(
        modifier = Modifier.fillMaxWidth(),
        horizontalAlignment = Alignment.CenterHorizontally,
        verticalArrangement = Arrangement.spacedBy(spacing.dp),
    ) {
        content()
    }
}

@Composable
fun PageIndicatorInteractive(count: Int) {
    var index by rememberSaveable { mutableIntStateOf(0) }
    PageIndicatorCentered(12) {
        PageIndicator(count = count, index = index, onIndexChange = { index = it })
        Text("Page ${index + 1} of $count", variant = TextVariant.Muted)
    }
}
```

## API Reference

### PageIndicator

## Accessibility

- The indicator is a single element with the `adjustable` role, and the dots are not focusable on their own.
- Its value is announced as "2 of 5".
- When `onIndexChange` is set, VoiceOver and TalkBack users swipe up or down to move to the next or previous page.
- Animations respect the system reduce motion setting.

## Notes

- Uses `bg-label` or `bg-accent` for the active dot and `bg-label-quaternary` for the others; colors follow the system appearance.