# Toggle (Notchset): prompt.md (v1.0.0)

- id: `toggle` · version 1.0.0 · component · free
- category: Actions
- build: Base UI (this item also ships a Radix build)
- install (this build): `npx shadcn@latest add https://beautiful-ui.dev/r/toggle.json`
- npm dependencies: @base-ui/react@^1, class-variance-authority@^0.7
- registry dependencies: utils, https://beautiful-ui.dev/r/notchset-foundation.json
- docs: https://beautiful-ui.dev/components/toggle
- The install command carries everything this item needs (files, CSS, tokens, npm and registry dependencies). Prefer it to copying source by hand.

shadcn's Toggle in Notchset, plus the latch: a key that stays down on its plate while on, its node lit and its sub-label flipping to ON. State reads from position as well as colour.

## Build it
- Stack: React 19 (`ref` is a plain prop), TypeScript, Tailwind CSS v4 utilities, a shadcn-initialised project with the `@/*` alias.
- Packages: `@base-ui/react@^1`, `class-variance-authority@^0.7` (Base UI build); `class-variance-authority@^0.7`, `radix-ui@^1` (Radix build).
- Files: `components/ui/notchset/toggle.tsx`; shared code: `lib/beautiful-ui/notchset/toggle.tsx`, `lib/beautiful-ui/notchset/instrument.tsx`, `lib/beautiful-ui/notchset/root.ts`.
- Registry dependencies, installed with it automatically: shadcn `utils` (cn), `notchset-foundation`.
- Builds: separate Base UI and Radix files. Install the one that matches the project (see Install): a free item's bare URL installs the Base UI build of it and its dependencies.
- Exports to keep: `Toggle`, `toggleVariants`, and every exported type.
- CSS: the install adds the notchset foundation (tokens, keyframes, motion levels) to your global stylesheet once. Nothing to import by hand.
- Re-running `add` (or `--overwrite`) re-applies those rules: put overrides in your own CSS, never in the installed rules.
- Tokens: retheme with the `--notchset-*` custom properties (`--notchset-check`, `--notchset-control-edge`, `--notchset-draw-from`, `--notchset-ease-bloom`, `--notchset-ease-travel`, `--notchset-fade`, `--notchset-focus-color`, `--notchset-focus-inset`, `--notchset-life-from`, `--notchset-life-ms`, `--notchset-node-blink`, `--notchset-node-bloom`, `--notchset-node-delay`, `--notchset-plate-color`, `--notchset-rise-from`, `--notchset-rule`, `--notchset-scroll`, `--notchset-signal`, `--notchset-sweep-to`). Never add Tailwind colour classes inside the component.

```tsx
import { Toggle } from "@/components/ui/notchset/toggle";
```

## Parts

| Part | data-slot | What it is for |
|---|---|---|
| `Toggle` | `toggle` | The key (and, as a latch, its plate and node). |
| `Latch` | `toggle-latch` | The latch's frame: node above, key on its plate. |

Style a part with `[data-slot="<slot>"]` selectors or its `className`; keep the attributes when editing.

## Sound
- Keep every `data-slot` and `data-sound` attribute: the sound layer reads them.
- Installing this item adds no audio. Nothing plays until the app mounts `SoundProvider` once (install: `npx shadcn@latest add https://beautiful-ui.dev/r/notchset-sound.json`, import from `@/components/ui/notchset/sound-provider`); `useSound()` gives `muted` and `setMuted` for a mute control. Without a provider the audio engine never loads.

## Match the original
- Read `components/ui/notchset/toggle.tsx` as the reference implementation before changing or recreating anything, and match it: sizes, colours per theme, motion timings, copy and behaviour.
- If you deviate (a prop you can't honour, a style you changed, a dependency you swapped), say so in your reply, part by part.
- Keep the accessibility contract, the keyboard map and the motion levels listed below.

## Use it when
- toggle, latch, on off key, pressed button, toolbar toggle, option key, Notchset
- Options that stay on: stream logs, verbose output, pin a run
- A drop-in for shadcn's Toggle: same exports, variants and sizes

### Not when
- Settings that save immediately: use a Switch
- One choice from several: use Button Group

## Mistakes
- Give a latch a description, or it has only its name

## Usage

```tsx
"use client";

import * as React from "react";
import { Toggle } from "@/components/ui/notchset/toggle";

export function StreamLogs() {
  const [stream, setStream] = React.useState(true);
  return (
    <Toggle variant="latch" description="LOGS" pressed={stream} onPressedChange={setStream}>
      STREAM
    </Toggle>
  );
}
```

## Props

| Prop | Type | Default | What it does |
|---|---|---|---|
| `variant` | `"default" \| "outline" \| "latch"` |  | shadcn's two, plus the instrument latch. |
| `size` | `"default" \| "sm" \| "lg"` |  | shadcn's sizes. |
| `pressed / defaultPressed / onPressedChange` | `boolean / (pressed) => void` |  | As shadcn. |
| `description` | `string` |  | The latch's sub-label while off; it flips to onLabel while on. |
| `onLabel` | `string` |  | Default "ON". |
| `node` | `boolean` |  | The latch's node above the key. Default true. |

Full docs: https://beautiful-ui.dev/components/toggle

## Customising
- Colours: the component reads your shadcn tokens (`--background`, `--foreground`, `--border` …), refined by the `--notchset-*` tokens. The signal colour is `--notchset-signal` (it falls back to `--destructive`). Set tokens on `:root`, or on any container to retheme one area.
- Dark mode follows the `.dark` class on an ancestor (the shadcn and next-themes convention).
- Update later by re-running the install with `--overwrite` (review the diff if you edited it). Changelog: https://beautiful-ui.dev/r/changelog.json

## Keyboard

| Keys | Action |
|---|---|
| Enter / Space | Toggle |

## Performance

- Latching is a CSS transition on the plate and node; state comes from aria-pressed, read without effects.

## Responsive

- Fixed height per size; labels stay on one line.
- 44px on touch screens.

## Motion inventory

| Interaction | What moves |
|---|---|
| Latch | The key travels 2px onto its plate and stays; release springs back in 200ms cubic-bezier(.34,1.5,.5,1); the node blooms after 60ms; the sub-label flips |

## Accessibility contract (preserve when editing)
- aria-pressed from the Base UI or Radix primitive
- On is shown by position (the key stays down) and the node, not colour alone
- Focus-visible crop marks only

## Install

Base UI project (a base-* style in components.json):

```bash
npx shadcn@latest add https://beautiful-ui.dev/r/toggle.json
```

Radix project (a radix-*, new-york or default style):

```bash
npx shadcn@latest add https://beautiful-ui.dev/r/radix-nova/toggle.json
```

Or add the `@beautiful-ui` registry to components.json and run `npx shadcn@latest add @beautiful-ui/toggle`: the CLI picks the build from your style.

## Credits
- Built on shadcn/ui (https://ui.shadcn.com)

## Source (Base UI build)

### components/ui/notchset/toggle.tsx

```tsx
"use client";

/**
 * Toggle (Notchset) v1.0.0 · Beautiful UI, by Chimpy (https://x.com/stochastichimp)
 * Docs: https://beautiful-ui.dev/components/toggle · Agent prompt: https://beautiful-ui.dev/md/toggle.md
 * MIT licensed: free to use, change and share.
 */

import * as React from "react";
import { Toggle as TogglePrimitive } from "@base-ui/react/toggle";
import type { VariantProps } from "class-variance-authority";
import { cn } from "@/lib/utils";
import { OWN_SOUND, NOTCHSET_ROOT, playCue, useComposedRefs } from "@/lib/beautiful-ui/notchset/instrument";
import { LatchFace, LatchFrame, TOGGLE_FOCUS, toggleVariants, usePressedState } from "@/lib/beautiful-ui/notchset/toggle";

/*
 * Notchset Toggle (Base UI build). shadcn's Toggle in Notchset; variant="latch" is the instrument latch:
 * a 96×40 key that stays down on its plate while on, its node lit, its sub-label flipping to ON.
 * Same exports, variants, sizes and data-slot as shadcn. The primitive owns the pressed state; the
 * latch reads it back, so it never disagrees (in a toggle group too).
 */

function Toggle({
  className,
  variant = "default",
  size = "default",
  description,
  onLabel,
  node,
  onPressedChange,
  children,
  ref,
  ...props
}: TogglePrimitive.Props &
  VariantProps<typeof toggleVariants> & {
    /** The latch's sub-label while off ("LOGS"); it flips to `onLabel` while on. */
    description?: string;
    onLabel?: string;
    /** The latch's node above the key. Default true. */
    node?: boolean;
  }) {
  const [on, setEl] = usePressedState(Boolean(props.pressed ?? props.defaultPressed));
  const keyRef = React.useRef<HTMLButtonElement>(null);
  const composed = useComposedRefs<HTMLButtonElement>(ref, keyRef);
  const refs = useComposedRefs<HTMLButtonElement>(composed, setEl);
  const key = (
    <TogglePrimitive
      {...(variant === "latch" ? OWN_SOUND : NOTCHSET_ROOT)}
      ref={refs}
      data-slot="toggle"
      data-variant={variant}
      data-size={size}
      onPressedChange={(next, details) => {
        onPressedChange?.(next, details);
        if (!details.isCanceled) playCue(keyRef.current, variant === "latch" ? "latch" : "tick");
      }}
      className={(state) => cn(TOGGLE_FOCUS, toggleVariants({ variant, size }), typeof className === "function" ? className(state) : className)}
      {...props}
    >
      {variant === "latch" ? (
        <LatchFace on={on} description={description} onLabel={onLabel}>
          {children as React.ReactNode}
        </LatchFace>
      ) : (
        children
      )}
    </TogglePrimitive>
  );
  return variant === "latch" ? (
    <LatchFrame on={on} node={node}>
      {key}
    </LatchFrame>
  ) : (
    key
  );
}

export { Toggle, toggleVariants };
```

### lib/beautiful-ui/notchset/toggle.tsx

```tsx
"use client";

import * as React from "react";
import { cva } from "class-variance-authority";
import { FlipText, Node, NOTCHSET_ROOT } from "@/lib/beautiful-ui/notchset/instrument";

/*
 * Notchset Toggle (the latch), shared by both builds: a key on its plate that stays down while it is
 * on. Two lines inside, the name and a sub-label that flips between ON and its description, and a
 * node above that lights. Position reports the state as well as colour. With plain children (an
 * icon, one word) it is shadcn's Toggle in Notchset: square, flat, ink when pressed.
 */

const toggleVariants = cva(
  "inline-flex shrink-0 cursor-pointer items-center justify-center gap-2 rounded-none border border-solid font-mono font-medium tracking-[0.08em] uppercase select-none disabled:pointer-events-none disabled:opacity-40 [&_svg]:pointer-events-none [&_svg]:shrink-0 [&_svg:not([class*='size-'])]:size-4",
  {
    variants: {
      variant: {
        default: "border-transparent bg-transparent text-foreground hover:bg-accent data-[pressed]:bg-primary data-[pressed]:text-primary-foreground data-[state=on]:bg-primary data-[state=on]:text-primary-foreground",
        outline: "border-[var(--notchset-control-edge,var(--input))] bg-background text-foreground hover:border-foreground data-[pressed]:border-foreground data-[pressed]:bg-accent data-[state=on]:border-foreground data-[state=on]:bg-accent",
        latch:
          "relative h-10 w-24 flex-col !items-start !justify-center !gap-[5px] border-[var(--notchset-control-edge,var(--input))] bg-background px-2.5 text-left text-foreground transition-[transform,background-color,border-color] duration-[var(--notchset-key-up),120ms,120ms] ease-[var(--notchset-ease-key-up),linear,linear] hover:border-foreground active:translate-x-[2px] active:translate-y-[2px] active:duration-[var(--notchset-key-down)] active:ease-linear data-[pressed]:translate-x-[2px] data-[pressed]:translate-y-[2px] data-[pressed]:border-foreground data-[pressed]:bg-accent data-[state=on]:translate-x-[2px] data-[state=on]:translate-y-[2px] data-[state=on]:border-foreground data-[state=on]:bg-accent pointer-coarse:h-11",
      },
      size: {
        default: "h-8 min-w-8 px-2 text-[11px]",
        sm: "h-7 min-w-7 px-1.5 text-[10px]",
        lg: "h-10 min-w-10 px-2.5 text-[12px]",
      },
    },
    compoundVariants: [{ variant: "latch", class: "h-10 w-24 px-2.5" }],
    defaultVariants: { variant: "default", size: "default" },
  },
);

/** The latch's inside: the name, and a sub-label that flips between ON and the description. */
function LatchFace({ on, children, description, onLabel = "ON" }: { on: boolean; children: React.ReactNode; description?: string; onLabel?: string }) {
  return (
    <>
      <span data-slot="toggle-label" className="text-[10.5px] leading-none font-medium tracking-[0.08em]">
        {children}
      </span>
      {description !== undefined && (
        <span data-slot="toggle-description" className={on ? "text-[8px] leading-none font-normal tracking-[0.1em] text-foreground" : "text-[8px] leading-none font-normal tracking-[0.1em] text-muted-foreground"}>
          <FlipText>{on ? onLabel : description}</FlipText>
        </span>
      )}
    </>
  );
}

/** A latch with its plate behind it and its node above. */
function LatchFrame({ on, node = true, children }: { on: boolean; node?: boolean; children: React.ReactNode }) {
  return (
    <span {...NOTCHSET_ROOT} data-slot="toggle-latch" className="inline-flex flex-col items-center gap-2.5">
      {node && <Node state={on ? "on" : "off"} delay={on ? 60 : 0} />}
      <span className="relative inline-flex [--notchset-plate-color:var(--notchset-control-edge,var(--input))] has-[[aria-pressed=true]]:[--notchset-plate-color:var(--foreground)] has-[:hover]:[--notchset-plate-color:var(--foreground)]">
        <span aria-hidden data-slot="plate" className={`notchset-plate`} />
        {children}
      </span>
    </span>
  );
}

/**
 * The key's real pressed state, read from the primitive's aria-pressed, so the latch's node and
 * sub-label always agree with it (controlled, uncontrolled or driven by a toggle group). Pass the
 * returned callback as a ref; the server renders `initial`.
 */
function usePressedState(initial: boolean) {
  const [el, setEl] = React.useState<HTMLElement | null>(null);
  const subscribe = React.useCallback(
    (onChange: () => void) => {
      if (!el) return () => {};
      const mo = new MutationObserver(onChange);
      mo.observe(el, { attributes: true, attributeFilter: ["aria-pressed"] });
      return () => mo.disconnect();
    },
    [el],
  );
  const pressed = React.useSyncExternalStore(
    subscribe,
    () => (el ? el.getAttribute("aria-pressed") === "true" : initial),
    () => initial,
  );
  return [pressed, setEl] as const;
}

/** The class Notchset adds to every key, kept out of the cva string so the build can split it. */
const TOGGLE_FOCUS = `notchset-focus`;

export { LatchFace, LatchFrame, TOGGLE_FOCUS, toggleVariants, usePressedState };
```

### lib/beautiful-ui/notchset/instrument.tsx

```tsx
"use client";

import * as React from "react";
import { cn } from "@/lib/utils";

/*
 * Notchset instrument parts, shared by every member of a pack: the node (a round light that reports
 * state), the legend printed above a control, the plate a key presses onto, the traced check, the
 * five-tick scanner, and the glyph flip that lands a changed label left to right. Nodes and checks
 * are inline SVG (round at every DPR); the CSS lives in the Notchset foundation. Also: the one motion
 * policy (reduced motion or a data-motion="off" ancestor), ref composition, the portal container
 * and the sound attributes every Notchset root carries.
 */

// ---------------------------------------------------------------------------------------------
// Motion, refs, portals, sound
// ---------------------------------------------------------------------------------------------

/** True under prefers-reduced-motion or inside a data-motion="off" scope. Checked when an effect runs. */
/**
 * Whether motion is off for an element, kept live: it follows the OS reduced-motion setting and any
 * data-motion attribute change above it, so a preference switched mid-playback stops decoration at once.
 */
export function useMotionOff(ref: React.RefObject<Element | null>) {
  const [off, setOff] = React.useState(false);
  React.useEffect(() => {
    const read = () => setOff(motionOff(ref.current));
    const r = requestAnimationFrame(read);
    const mq = window.matchMedia?.("(prefers-reduced-motion: reduce)");
    mq?.addEventListener?.("change", read);
    const mo = new MutationObserver(read);
    mo.observe(document.documentElement, { attributes: true, attributeFilter: ["data-motion"], subtree: true });
    return () => {
      cancelAnimationFrame(r);
      mq?.removeEventListener?.("change", read);
      mo.disconnect();
    };
  }, [ref]);
  return off;
}

/**
 * The microphone, or a rejection after `timeoutMs` (a prompt left open, a denied permission). A stream
 * that arrives after the timeout is stopped at once, so a late "Allow" never leaves the mic on.
 */
export function requestMic(timeoutMs = 5000): Promise<MediaStream> {
  if (typeof navigator === "undefined" || !navigator.mediaDevices?.getUserMedia) return Promise.reject(new Error("no mic"));
  const ask = navigator.mediaDevices.getUserMedia({ audio: true });
  return new Promise((resolve, reject) => {
    let late = false;
    const t = setTimeout(() => {
      late = true;
      reject(new Error("timeout"));
    }, timeoutMs);
    ask.then(
      (stream) => {
        clearTimeout(t);
        if (late) stream.getTracks().forEach((track) => track.stop());
        else resolve(stream);
      },
      (err) => {
        clearTimeout(t);
        reject(err);
      },
    );
  });
}

export function motionOff(el: Element | null | undefined) {
  if (typeof window === "undefined") return true;
  if (window.matchMedia?.("(prefers-reduced-motion: reduce)").matches) return true;
  return Boolean(el?.closest('[data-motion="off"]'));
}

function assignRef<T>(ref: React.Ref<T> | undefined, node: T | null): () => void {
  if (typeof ref === "function") {
    const cleanup = ref(node);
    return typeof cleanup === "function" ? cleanup : () => ref(null);
  }
  if (ref) (ref as React.RefObject<T | null>).current = node;
  return () => {
    if (ref) (ref as React.RefObject<T | null>).current = null;
  };
}

/** Composes two refs, keeping React 19 ref cleanups. */
export function useComposedRefs<T>(a: React.Ref<T> | undefined, b: React.Ref<T> | undefined): React.RefCallback<T> {
  return React.useCallback(
    (node: T | null) => {
      const release = [assignRef(a, node), assignRef(b, node)];
      return () => release.forEach((f) => f());
    },
    [a, b],
  );
}

/** Runs ours after theirs, unless theirs called preventDefault. */
export function composeHandler<E extends { defaultPrevented: boolean }>(theirs: ((e: E) => void) | undefined, ours: (e: E) => void) {
  return (e: E) => {
    theirs?.(e);
    if (!e.defaultPrevented) ours(e);
  };
}

/** Keeps the latest value in a ref, for callbacks read inside timers and animation frames. */
export function useLatest<T>(value: T) {
  const ref = React.useRef(value);
  React.useLayoutEffect(() => {
    ref.current = value;
  });
  return ref;
}

/*
 * Where Notchset overlays (menus, popovers, tooltips) portal to. Unset, document.body, as shadcn's
 * do. Provide an element to keep them inside a scoped theme: a preview, a widget, a shadow root.
 */
export const NotchsetPortalContext = React.createContext<HTMLElement | null>(null);
export function useNotchsetPortal(): HTMLElement | undefined {
  return React.useContext(NotchsetPortalContext) ?? undefined;
}

export { NOTCHSET_ROOT, OWN_SOUND } from "@/lib/beautiful-ui/notchset/root";

// ---------------------------------------------------------------------------------------------
// Parts
// ---------------------------------------------------------------------------------------------

export type NodeState = "off" | "on" | "live" | "signal";

/** The node: a 9×9 ring whose dot blooms on (`on`), blinks (`live`) or turns signal. */
function Node({ state = "off", delay, className, style, ...props }: Omit<React.ComponentProps<"svg">, "children"> & { state?: NodeState; delay?: number }) {
  return (
    <svg
      aria-hidden
      data-slot="indicator"
      data-state={state}
      width="9"
      height="9"
      viewBox="0 0 9 9"
      className={cn(`notchset-node`, className)}
      style={delay ? ({ "--notchset-node-delay": `${delay}ms`, ...style } as React.CSSProperties) : style}
      {...props}
    >
      <circle data-slot="indicator-ring" cx="4.5" cy="4.5" r="3.25" fill="none" strokeWidth="1" />
      <circle data-slot="indicator-dot" cx="4.5" cy="4.5" />
    </svg>
  );
}

/** A small solid round mark (the node where a leader meets a popup, a pointer): SVG, round at every DPR. */
function Dot({ size = 7, className, style }: { size?: number; className?: string; style?: React.CSSProperties }) {
  return (
    <svg aria-hidden width={size} height={size} viewBox={`0 0 ${size} ${size}`} className={cn("pointer-events-none absolute overflow-visible", className)} style={style}>
      <circle cx={size / 2} cy={size / 2} r={size / 2} fill="currentColor" />
    </svg>
  );
}

/** The legend: a mono label above a control, with an optional node (or any trailing reading). */
function Legend({ label, node, children, className, ...props }: React.ComponentProps<"div"> & { label?: React.ReactNode; node?: NodeState }) {
  return (
    <div data-slot="legend" className={cn(`notchset-legend`, className)} {...props}>
      <span data-slot="legend-label">{label}</span>
      {(children != null || node) && (
        <span data-slot="legend-reading" className="flex items-center gap-2">
          {children}
          {node && <Node state={node} />}
        </span>
      )}
    </div>
  );
}

/** A key on its plate: the plate is an offset frame behind the child; `--notchset-plate-color` tints it. */
function Plated({ className, children, ...props }: React.ComponentProps<"span">) {
  return (
    <span data-slot="plated" className={cn("relative inline-flex", className)} {...props}>
      <span aria-hidden data-slot="plate" className={`notchset-plate`} />
      {children}
    </span>
  );
}

/**
 * The success check. Mounted, it traces itself in over --notchset-check (instant under reduced
 * motion); pass `drawn` to drive the trace yourself.
 */
function Check({ drawn, size = 16 }: { drawn?: boolean; size?: number }) {
  return (
    <svg aria-hidden data-slot="check" width={size} height={size} viewBox="0 0 24 24">
      <path
        d="M4 12.5 L9.5 18 L20 6"
        fill="none"
        stroke="currentColor"
        strokeWidth={1.75}
        strokeLinecap="square"
        pathLength={1}
        strokeDasharray={1}
        className={drawn === undefined ? `notchset-check-draw` : undefined}
        style={drawn === undefined ? undefined : { strokeDashoffset: drawn ? 0 : 1, transition: "stroke-dashoffset var(--notchset-check) var(--notchset-ease-travel)" }}
      />
    </svg>
  );
}

/** The scanner: five 1px ticks fading in turn while something works (static, centre lit, when motion is off). */
function Scanner({ height = 12 }: { height?: number }) {
  return (
    <span aria-hidden data-slot="scanner" className={cn(`notchset-scanner`, "inline-flex items-end gap-[2px]")} style={{ height }}>
      {[0.82, 0.66, 1, 0.66, 0.82].map((h, i) => (
        <span key={i} className="w-px bg-current" style={{ height: height * h, animationDelay: `${i * 140 - 700}ms` }} />
      ))}
    </span>
  );
}

// ---------------------------------------------------------------------------------------------
// Glyph flip: each character cycles through glyphs and lands at 110 + i·14ms, left to right
// ---------------------------------------------------------------------------------------------

const GLYPHS = "ABCDEFGHJKLMNPRSTUVWXYZ0123456789#/+=";
const STILL = new Set([" ", "·", "/", ".", ":"]);

export function scramble(text: string, elapsed: number) {
  let out = "";
  for (let i = 0; i < text.length; i++) {
    const ch = text[i]!;
    out += STILL.has(ch) || elapsed >= 110 + i * 14 ? ch : GLYPHS[(Math.floor(elapsed / 36) * 5 + i * 11) % GLYPHS.length];
  }
  return out;
}

/**
 * The text to show for `text`: when it changes, a few frames of glyphs that land left to right.
 * Runs on requestAnimationFrame only while a flip is active; the settled text is never state. Off
 * under reduced motion, inside data-motion="off" (pass the element) or with `off`.
 */
export function useGlyphFlip(text: string, { off = false, el }: { off?: boolean; el?: React.RefObject<Element | null> } = {}) {
  const [frame, setFrame] = React.useState<{ for: string; shown: string } | null>(null);
  const first = React.useRef(true);
  React.useEffect(() => {
    if (first.current) {
      first.current = false;
      return;
    }
    if (off || motionOff(el?.current)) return;
    let raf = 0;
    const t0 = performance.now();
    const end = 110 + text.length * 14 + 40;
    const step = (now: number) => {
      const elapsed = now - t0;
      if (elapsed >= end) return setFrame(null);
      setFrame({ for: text, shown: scramble(text, elapsed) });
      raf = requestAnimationFrame(step);
    };
    raf = requestAnimationFrame(step);
    return () => cancelAnimationFrame(raf);
  }, [text, off, el]);
  return frame && frame.for === text ? frame.shown : text;
}

/** A label that flips when its text changes; screen readers read the final text only. */
function FlipText({ children, off, className, ...props }: Omit<React.ComponentProps<"span">, "children"> & { children: string; off?: boolean }) {
  const ref = React.useRef<HTMLSpanElement>(null);
  const shown = useGlyphFlip(children, { off, el: ref });
  return (
    <span ref={ref} data-slot="flip-text" className={cn("relative whitespace-nowrap", className)} {...props}>
      <span aria-hidden>{shown}</span>
      <span className="sr-only">{children}</span>
    </span>
  );
}

// ---------------------------------------------------------------------------------------------
// Sound: Notchset components announce cues; the page's beautiful-ui-sound layer (opt-in) plays them.
// ---------------------------------------------------------------------------------------------

/** The Notchset cues, in the shared sound layer's names (played in the mechanical voice). */
export const NOTCHSET_CUES = { tap: "tap", latch: "lock", signal: "destructive", confirm: "halt", done: "success", tick: "tick" } as const;
export type NotchsetCue = keyof typeof NOTCHSET_CUES;

export function playCue(el: Element | null, cue: NotchsetCue) {
  if (!el || typeof CustomEvent === "undefined" || el.closest('[data-sound="off"]')) return;
  el.dispatchEvent(new CustomEvent("beautiful-ui:sound", { bubbles: true, detail: { cue: NOTCHSET_CUES[cue] } }));
}

// ---------------------------------------------------------------------------------------------
// Shortcuts: "⌘↵" → "Meta+Enter Control+Enter" (aria-keyshortcuts)
// ---------------------------------------------------------------------------------------------

const KEY_NAMES: Record<string, string> = { "⌘": "Meta", "⌃": "Control", "⌥": "Alt", "⇧": "Shift", "↵": "Enter", "⏎": "Enter", "⎋": "Escape", "⌫": "Backspace", "⇥": "Tab", "␣": "Space" };

export function kbdToShortcut(kbd: string | undefined): string | undefined {
  if (!kbd) return undefined;
  const parts = [...kbd.replace(/\s+/g, "")].map((c) => KEY_NAMES[c] ?? c.toUpperCase());
  if (!parts.length) return undefined;
  const combo = parts.join("+");
  // ⌘ on a Mac is Ctrl elsewhere: announce both.
  return combo.includes("Meta") ? `${combo} ${combo.replace("Meta", "Control")}` : combo;
}

/**
 * A number that rolls: each digit is a 0–9 strip; the ones digit moves first and each digit to its left
 * 40ms later (620ms, a small overshoot). `delay` offsets the whole number (rows 60ms apart). Non-digits
 * (",", "$", "%") sit still. Screen readers get the plain value.
 */
function RollingNumber({ value, height = 32, delay = 0, className }: { value: string | number; height?: number; delay?: number; className?: string }) {
  const text = String(value);
  const digits = text.split("");
  const lastDigit = digits.reduce((n, d, i) => (/\d/.test(d) ? i : n), -1);
  return (
    <span className={cn("relative inline-flex overflow-hidden tabular-nums", className)} style={{ height, lineHeight: `${height}px` }}>
      <span className="sr-only">{text}</span>
      <span aria-hidden className="flex">
        {digits.map((d, i) =>
          /\d/.test(d) ? (
            <span
              key={digits.length - i}
              className="flex flex-col transition-transform duration-[620ms] ease-[cubic-bezier(.34,1.15,.5,1)]"
              style={{ transform: `translateY(${-Number(d) * height}px)`, transitionDelay: `${delay + (lastDigit - i) * 40}ms` }}
            >
              {Array.from({ length: 10 }, (_, n) => (
                <span key={n} style={{ height }}>
                  {n}
                </span>
              ))}
            </span>
          ) : (
            <span key={`s${digits.length - i}`}>{d}</span>
          ),
        )}
      </span>
    </span>
  );
}

export { Check, Dot, FlipText, Legend, Node, Plated, RollingNumber, Scanner };
```

### lib/beautiful-ui/notchset/root.ts

```tsx
/*
 * Notchset's root attributes, server-safe (no client directive), so server components can spread
 * them too. Every Notchset root (and portalled popup) carries data-notchset (the motion policy's
 * scope), plays its own cues in the mechanical voice, and keeps the page's click layer out.
 */
export const NOTCHSET_ROOT = { "data-notchset": "", "data-sound": "none", "data-sound-voice": "analogue" } as const;

/** On every interactive element: it plays its own cues, so the page's click layer adds no tap. */
export const OWN_SOUND = { "data-sound": "none" } as const;
```

The notchset foundation (the tokens listed above, keyframes and motion levels) installs once with the first component; its CSS is public at https://beautiful-ui.dev/r/notchset-foundation.json.