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

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

shadcn's Checkbox in Notchset: a 16px square whose check draws in, a mixed dash and a press dip; and CheckboxTree, a tri-state parent with its own collapse key over child rules on a rail.

## 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` (Base UI build); `radix-ui@^1` (Radix build).
- Files: `components/ui/notchset/checkbox.tsx`; shared code: `lib/beautiful-ui/notchset/checkbox.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: `Checkbox`, `CheckboxTree`, 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 { CheckboxTree } from "@/components/ui/notchset/checkbox";
```

## Parts

| Part | data-slot | What it is for |
|---|---|---|
| `Checkbox` | `checkbox` | The box. |
| `CheckboxTree` | `checkbox-tree` | The group. |

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/checkbox.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
- checkbox, check all, tri-state, indeterminate, settings toggles, shadcn checkbox, Notchset
- On/off choices that sit in a list
- A parent that checks a group

### Not when
- A single setting that applies at once: use Switch

## Mistakes
- Clicking the parent row toggles every child; the chevron only folds

## Usage

```tsx
"use client";

import * as React from "react";
import { CheckboxTree } from "@/components/ui/notchset/checkbox";

const rules = [
  { id: "cost", label: "Cost over budget" },
  { id: "latency", label: "P95 latency over 400ms" },
  { id: "failures", label: "Failure rate over 2%" },
];

export function AlertRules() {
  const [on, setOn] = React.useState<string[]>(["cost"]);
  return <CheckboxTree label="All alerts" items={rules} value={on} onValueChange={setOn} />;
}
```

## Props

| Prop | Type | Default | What it does |
|---|---|---|---|
| `Checkbox` | `as the primitive + indeterminate` |  | shadcn's API; indeterminate shows the dash. |
| `CheckboxTree` | `{ label, items, value, onValueChange, meta?, defaultOpen? }` |  | The parent, collapse key and child rows. |

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

## 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 |
|---|---|
| Space | Toggle |
| Tab | Next checkbox or the collapse key |

## Performance

- CSS only; the check is a stroke-dashoffset transition.

## Responsive

- Rows fill their container; labels truncate.

## Motion inventory

| Interaction | What moves |
|---|---|
| Check | The check draws in (260ms after 60ms) |
| Mixed | A dash scales in (240ms) |
| Fold | Children unroll (380ms) or roll up (260ms after 60ms); rows settle in 50ms apart |

## Accessibility contract (preserve when editing)
- Native checkbox semantics; the parent is aria-checked=mixed when some are on
- The collapse key has aria-expanded and aria-controls; folded children are inert

## Install

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

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

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

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

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

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

## Source (Base UI build)

### components/ui/notchset/checkbox.tsx

```tsx
"use client";

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

import * as React from "react";
import { Checkbox as CheckboxPrimitive } from "@base-ui/react/checkbox";
import { cn } from "@/lib/utils";
import { NOTCHSET_ROOT, OWN_SOUND, playCue } from "@/lib/beautiful-ui/notchset/instrument";
import { CheckboxMarks, TreeRail, checkboxClass, checkboxRowClass } from "@/lib/beautiful-ui/notchset/checkbox";

/*
 * Notchset Checkbox (Base UI build). shadcn's Checkbox, same API, in Notchset: a 16px square whose
 * check draws in, a mixed dash, and a press dip. CheckboxTree is the designed group: a tri-state
 * parent row that toggles every child, its own collapse key, and children that unfold on a rail.
 */

const withClass =
  <S,>(base: string, className: string | ((state: S) => string | undefined) | undefined) =>
  (state: S) =>
    cn(base, typeof className === "function" ? className(state) : className);

function Checkbox({ className, onCheckedChange, ...props }: CheckboxPrimitive.Root.Props) {
  return (
    <CheckboxPrimitive.Root
      {...NOTCHSET_ROOT}
      data-slot="checkbox"
      onCheckedChange={(c, d) => {
        onCheckedChange?.(c, d);
        playCue(document.activeElement, "tick");
      }}
      className={withClass(checkboxClass, className)}
      {...props}
    >
      <CheckboxMarks />
    </CheckboxPrimitive.Root>
  );
}

export type CheckboxTreeItem = { id: string; label: React.ReactNode; meta?: React.ReactNode };

/** A parent that checks all, a collapse key, and child rows on a rail (380ms open, 260ms close). */
function CheckboxTree({
  label,
  meta,
  items,
  value,
  onValueChange,
  defaultOpen = true,
  labels,
  className,
}: {
  label: React.ReactNode;
  meta?: (on: number, of: number) => React.ReactNode;
  items: readonly CheckboxTreeItem[];
  value: readonly string[];
  onValueChange: (value: string[]) => void;
  defaultOpen?: boolean;
  labels?: { show?: string; hide?: string };
  className?: string;
}) {
  const uid = React.useId();
  const [open, setOpen] = React.useState(defaultOpen);
  const on = items.filter((i) => value.includes(i.id)).length;
  const all = on === items.length;
  const some = on > 0 && !all;
  return (
    <div {...NOTCHSET_ROOT} data-slot="checkbox-tree" className={cn("border-t border-b border-solid border-t-foreground border-b-[var(--notchset-rule,var(--border))]", className)}>
      {/* The row toggles its checkbox; the box's own click doesn't bubble, so nothing toggles twice. */}
      <div className={checkboxRowClass} onClick={() => onValueChange(all ? [] : items.map((i) => i.id))}>
        <Checkbox aria-labelledby={`${uid}-label`} checked={all} indeterminate={some} onClick={(e) => e.stopPropagation()} onCheckedChange={() => onValueChange(all ? [] : items.map((i) => i.id))} />
        <span id={`${uid}-label`} className="min-w-0 flex-1 font-sans text-sm font-medium [overflow-wrap:anywhere]">
          {label}
        </span>
        <span className="flex-none font-mono text-[8.5px] tracking-[0.06em] whitespace-nowrap text-muted-foreground tabular-nums">{meta ? meta(on, items.length) : `${on} OF ${items.length} ON`}</span>
        <button
          {...OWN_SOUND}
          type="button"
          aria-expanded={open}
          aria-controls={`${uid}-kids`}
          aria-labelledby={`${uid}-toggle ${uid}-label`}
          onClick={(e) => {
            e.stopPropagation();
            playCue(e.currentTarget, "tick");
            setOpen((o) => !o);
          }}
          className={cn(`notchset-focus`, "[--notchset-focus-inset:-3px] flex size-8 flex-none cursor-pointer items-center justify-center border-0 border-s border-solid border-[var(--notchset-rule,var(--border))] bg-transparent p-0 text-foreground pointer-coarse:size-11")}
        >
          <span id={`${uid}-toggle`} className="sr-only">
            {open ? (labels?.hide ?? "Hide") : (labels?.show ?? "Show")}
          </span>
          <svg aria-hidden width="10" height="10" viewBox="0 0 12 12" className={cn("transition-transform duration-[320ms] ease-[cubic-bezier(.34,1.5,.5,1)]", open && "rotate-180")}>
            <path d="M2.5 4.5 L6 8 L9.5 4.5" fill="none" stroke="currentColor" strokeWidth="1.4" strokeLinecap="square" />
          </svg>
        </button>
      </div>
      <div
        id={`${uid}-kids`}
        inert={!open || undefined}
        className={cn("grid transition-[grid-template-rows]", open ? "grid-rows-[1fr] duration-[380ms] ease-[var(--notchset-ease-unfold)]" : "grid-rows-[0fr] delay-[60ms] duration-[260ms] ease-[var(--notchset-ease-travel)]")}
      >
        <div className="min-h-0 overflow-hidden">
          {items.map((it, i) => (
            <div
              key={it.id}
              onClick={() => onValueChange(value.includes(it.id) ? value.filter((v) => v !== it.id) : [...value, it.id])}
              className={cn(
                checkboxRowClass,
                "ps-9 pe-1 first:border-t-[var(--notchset-rule,var(--border))] transition-[background-color,opacity,translate]",
                open ? "translate-y-0 opacity-100 duration-[120ms,200ms,380ms] ease-[linear,linear,cubic-bezier(.34,1.3,.5,1)]" : "-translate-y-1.5 opacity-0 duration-100",
              )}
              style={open ? { transitionDelay: `0ms, ${120 + i * 50}ms, ${120 + i * 50}ms` } : undefined}
            >
              <TreeRail last={i === items.length - 1} />
              <Checkbox
                aria-labelledby={`${uid}-item-${i}`}
                checked={value.includes(it.id)}
                onClick={(e) => e.stopPropagation()}
                onCheckedChange={(c) => onValueChange(c ? [...value, it.id] : value.filter((v) => v !== it.id))}
              />
              <span id={`${uid}-item-${i}`} className="min-w-0 flex-1 font-sans text-[13.5px] [overflow-wrap:anywhere]">
                {it.label}
              </span>
              {it.meta && <span className="flex-none font-mono text-[8.5px] tracking-[0.06em] whitespace-nowrap text-muted-foreground">{it.meta}</span>}
            </div>
          ))}
        </div>
      </div>
    </div>
  );
}

export { Checkbox, CheckboxTree };
```

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

```tsx
"use client";

import { cn } from "@/lib/utils";

/*
 * Notchset Checkbox parts, shared by both builds (handoff 1.11): the 16px box (edge at rest, ink on
 * hover, ink fill when checked) whose check draws in (260ms after 60ms), the mixed state's 6px dash
 * that scales in, and the press dip to .86. Plus the tree row used by CheckboxTree.
 */

export const checkboxClass = cn(
  `notchset-focus`,
  "group/cb [--notchset-focus-inset:-4px] peer relative inline-flex size-4 flex-none cursor-pointer items-center justify-center border border-solid border-[var(--notchset-control-edge,var(--input))] bg-background p-0 outline-none",
  "transition-[background-color,border-color,scale] duration-[120ms,120ms,160ms] ease-[linear,linear,var(--notchset-ease-bloom)] hover:border-foreground active:scale-[.86]",
  "data-[checked]:border-foreground data-[checked]:bg-foreground data-[indeterminate]:border-foreground data-[indeterminate]:bg-foreground",
  "data-[state=checked]:border-foreground data-[state=checked]:bg-foreground data-[state=indeterminate]:border-foreground data-[state=indeterminate]:bg-foreground",
  "data-[disabled]:cursor-not-allowed data-[disabled]:opacity-50 aria-invalid:border-[var(--notchset-signal-text,var(--destructive))]",
);

const CHECKED = "group-data-[checked]/cb:[stroke-dashoffset:0] group-data-[state=checked]/cb:[stroke-dashoffset:0] group-data-[checked]/cb:delay-[60ms] group-data-[state=checked]/cb:delay-[60ms] group-data-[checked]/cb:duration-[260ms] group-data-[state=checked]/cb:duration-[260ms]";
const MIXED = "group-data-[indeterminate]/cb:scale-x-100 group-data-[state=indeterminate]/cb:scale-x-100";

/** The check and the dash, drawn in the box's on-ink colour. Rendered always, so both can animate. */
export function CheckboxMarks() {
  return (
    <svg aria-hidden width="10" height="10" viewBox="0 0 10 10" className="pointer-events-none overflow-visible text-background">
      <path
        d="M1.6 5.2 L4 7.5 L8.6 2.4"
        fill="none"
        stroke="currentColor"
        strokeWidth="1.5"
        strokeLinecap="square"
        strokeDasharray="12"
        className={cn("[stroke-dashoffset:12] transition-[stroke-dashoffset] duration-[120ms] ease-[var(--notchset-ease-travel)] group-data-[indeterminate]/cb:[stroke-dashoffset:12] group-data-[state=indeterminate]/cb:[stroke-dashoffset:12]", CHECKED)}
      />
      <line x1="2" y1="5" x2="8" y2="5" stroke="currentColor" strokeWidth="1.5" className={cn("origin-center scale-x-0 [transform-box:fill-box] transition-transform duration-[240ms] ease-[cubic-bezier(.34,1.6,.5,1)]", MIXED)} />
    </svg>
  );
}

/** A 48px tree row: the checkbox, a label and a muted reading; children hang on a rail. */
export const checkboxRowClass = cn(
  "relative flex min-h-12 cursor-pointer items-center gap-3 py-1.5 border-t border-solid border-[var(--notchset-rule,var(--border))] ps-1 text-foreground transition-[background-color] duration-[120ms] ease-linear first:border-t-transparent hover:bg-[var(--notchset-faceplate,var(--card))]",
);

export function TreeRail({ last }: { last?: boolean }) {
  return (
    <>
      <span aria-hidden className={cn("absolute start-[11.5px] -top-px w-px bg-[var(--notchset-control-edge,var(--input))]", last ? "h-[25px]" : "h-[49px]")} />
      <span aria-hidden className="absolute start-3 top-[23.5px] h-px w-3.5 bg-[var(--notchset-control-edge,var(--input))]" />
    </>
  );
}
```

### 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.