# Textarea (Lumen Halo): prompt.md (v1.0.0)

- id: `lumen-textarea` · version 1.0.0 · component · free
- category: Inputs
- build: Base UI (one set of files; its dependencies follow the build)
- install (this build): `npx shadcn@latest add https://beautiful-ui.dev/r/lumen-textarea.json`
- npm dependencies: none
- registry dependencies: utils, https://beautiful-ui.dev/r/lumen-foundation.json
- docs: https://beautiful-ui.dev/components/lumen-textarea
- The install command carries everything this item needs (files, CSS, tokens, npm and registry dependencies). Prefer it to copying source by hand.

Room to think, and it grows as you write: the Input's recessed well, taller, with the same filament of light and the same honest shake. shadcn's Textarea, cut from Lumen glass.

## Build it
- Stack: React 19 (`ref` is a plain prop), TypeScript, Tailwind CSS v4 utilities, a shadcn-initialised project with the `@/*` alias.
- Packages: none beyond React.
- Files: `components/ui/lumen/textarea.tsx`; shared code: `lib/beautiful-ui/lumen/sound.ts`.
- Registry dependencies, installed with it automatically: shadcn `utils` (cn), `lumen-foundation`.
- Builds: one set of files for both, but its dependencies come in Base UI and Radix builds. 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: `Textarea`, and every exported type.
- CSS: the install merges this item's rules (the registry `css` field) into your global stylesheet, in `@layer components`, and adds the lumen foundation (tokens, keyframes, motion levels) 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 `--lumen-*` custom properties (`--lumen-accent`, `--lumen-accent-text`, `--lumen-bad`, `--lumen-bad-text`, `--lumen-focus`, `--lumen-good`, `--lumen-good-text`, `--lumen-hairline`, `--lumen-ink`, `--lumen-muted-ink`, `--lumen-series-1`, `--lumen-series-2`, `--lumen-series-3`, `--lumen-series-4`, `--lumen-series-5`, `--lumen-series-6`, `--lumen-warn`, `--lumen-warn-text`); this item's CSS also reads `--lumen-font-sans`, `--lumen-radius-k`. Never add Tailwind colour classes inside the component.

```tsx
import { Textarea } from "@/components/ui/lumen/textarea";
```

## Parts

| Part | data-slot | What it is for |
|---|---|---|
| `Textarea` | `textarea` | The growing well. |

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 `GlassSoundProvider` once (install: `npx shadcn@latest add https://beautiful-ui.dev/r/glass-sound.json`, import from `@/components/beautiful-ui/glass-sound`); `GlassSoundToggle` is its mute control. Without a provider the audio engine never loads.

## Match the original
- Read `components/ui/lumen/textarea.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
- textarea, multiline input, message, feedback, notes, comment box, shadcn textarea, Lumen
- Multi-line entry: feedback, notes, descriptions
- A drop-in for shadcn's Textarea: it grows with the text (field-sizing: content)
- With a character meter: put it in Lumen Input Group with InputGroupCount

### Not when
- One line: use Lumen Input

## Mistakes
- It grows without limit by default, like shadcn's: set a max-height
- Import from @/components/ui/lumen/textarea: it never replaces your own

## Usage

```tsx
import { Textarea } from "@/components/ui/lumen/textarea";

<Textarea placeholder="What should we build next?" style={{ maxHeight: 240 }} />
```

## Props

| Prop | Type | Default | What it does |
|---|---|---|---|
| `aria-invalid` | `boolean` |  | Coral ring and filament, one shake and the error cue. |
| `style={{ maxHeight }}` | `CSSProperties` |  | Cap the growth; it scrolls past it. |
| `rows / value / onChange / …` | `as shadcn` |  | Every native textarea attribute; className merges last with cn. |

Full docs: https://beautiful-ui.dev/components/lumen-textarea

## Customising
- Colours: set the `--lumen-*` tokens on `:root`, or on a container with the `lumen-scope` class to retheme one area. Add the `lumen-inherit` class to follow your shadcn palette instead (`--chart-N`, `--destructive`).
- 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 |
|---|---|
| Tab | Focus the field |

## Motion inventory

| Interaction | What moves |
|---|---|
| Focus | The filament grows along the bottom edge; accent ring and halo |
| Invalid | One .38s shake and the error cue when aria-invalid turns on |

## Accessibility contract (preserve when editing)
- A native <textarea>
- aria-invalid for errors; point aria-describedby at the message
- 16px text on phones so iOS never zooms

## Install

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

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

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

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

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

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

## Source (Base UI build)

### components/ui/lumen/textarea.tsx

```tsx
"use client";

/**
 * Textarea (Lumen Halo) v1.0.0 · Beautiful UI
 * Docs: https://beautiful-ui.dev/components/lumen-textarea · Agent prompt: https://beautiful-ui.dev/md/lumen-textarea.md
 * Licensed to the purchaser under the Beautiful UI license: https://beautiful-ui.dev/license
 */

import * as React from "react";
import { cn } from "@/lib/utils";
import { statusSpeaksFor, useCueOnChange, useMergedRef } from "@/lib/beautiful-ui/lumen/sound";

/*
 * Lumen Textarea. shadcn's Textarea in Lumen Halo: the Input's recessed well, taller, growing with
 * its text (field-sizing: content, as shadcn's; cap it with max-height). Focus draws the filament;
 * aria-invalid rings it coral and shakes it once, with an error cue through beautiful-ui-sound. For the
 * character meter, put it in an InputGroup with InputGroupCount.
 */

function Textarea({ className, ref, ...props }: React.ComponentProps<"textarea">) {
  const own = React.useRef<HTMLTextAreaElement>(null);
  const invalid = props["aria-invalid"] === true || props["aria-invalid"] === "true";
  useCueOnChange(own, invalid, (now) => (now && !statusSpeaksFor(own.current) ? "error" : null));
  const merged = useMergedRef(own, ref);
  return <textarea ref={merged} data-slot="textarea" className={cn(`lumen-textarea`, className)} {...props} />;
}

export { Textarea };
```

### lib/beautiful-ui/lumen/sound.ts

```tsx
"use client";

import * as React from "react";

/**
 * Asks the page's sound layer (beautiful-ui-sound) to play `cue`. Silent when nothing listens, and inside
 * anything marked data-sound="off". `index` pitches select cues by position. No audio code ships in
 * the components themselves.
 */
export function emitSound(el: Element | null, cue: string, force?: boolean, index?: number) {
  if (!el || typeof CustomEvent === "undefined" || el.closest('[data-sound="off"]')) return;
  el.dispatchEvent(new CustomEvent("beautiful-ui:sound", { bubbles: true, detail: { cue, force, index } }));
}

/**
 * Plays the cue `pick` returns whenever `value` changes (never on mount): an error when a field
 * turns invalid, a success when a check passes.
 */
export function useCueOnChange<T>(ref: React.RefObject<Element | null>, value: T, pick: (next: T, prev: T) => string | null) {
  const prev = React.useRef(value);
  const pickRef = React.useRef(pick);
  React.useEffect(() => {
    pickRef.current = pick;
  });
  React.useEffect(() => {
    if (Object.is(prev.current, value)) return;
    const before = prev.current;
    prev.current = value;
    const cue = pickRef.current(value, before);
    if (cue) emitSound(ref.current, cue);
  }, [ref, value]);
}

/** Points one ref (callback or object) at `node`; returns how to let go of it. */
function assign<T>(r: React.Ref<T> | undefined, node: T | null): () => void {
  if (typeof r === "function") {
    const cleanup = r(node);
    return typeof cleanup === "function" ? cleanup : () => r(null);
  }
  if (r) {
    (r as React.RefObject<T | null>).current = node;
    return () => ((r as React.RefObject<T | null>).current = null);
  }
  return () => {};
}

/**
 * One stable callback ref for the component's own ref and the caller's. It changes only when one of
 * them does, so a caller's callback ref isn't detached and reattached on every render, and it
 * honours React 19 ref cleanups.
 */
export function useMergedRef<T>(own: React.Ref<T> | undefined, theirs: React.Ref<T> | undefined): React.RefCallback<T> {
  return React.useCallback(
    (node: T | null) => {
      const release = [assign(own, node), assign(theirs, node)];
      return () => release.forEach((f) => f());
    },
    [own, theirs],
  );
}

/** True when `el` sits in an input group whose status part speaks for it (one cue per change). */
export const statusSpeaksFor = (el: Element | null) => Boolean(el?.closest('[data-slot="input-group"]')?.querySelector('[data-slot="input-group-status"]'));
```

### CSS (the registry `css` / `cssVars`, merged into the global stylesheet by the shadcn CLI)

```css
@layer components {
  .lumen-textarea {
    box-sizing: border-box;
    width: 100%;
    min-width: 0;
    margin: 0;
    border: none;
    outline: none;
    --lf-ring: var(--gc-wr);
    --lf-halo: 0 0 0 0 transparent;
    background-color: var(--lf-bg,var(--gc-well));
    box-shadow: inset 0 0 0 1px var(--lf-ring),var(--gc-wellIn),var(--lf-halo);
    background-image: linear-gradient(90deg,transparent,var(--lf-fil,var(--gc-acc)),transparent);
    background-repeat: no-repeat;
    background-position: 50% 100%;
    background-size: 0% 1px;
    font-family: var(--lumen-font-sans, var(--font-sans, var(--font-geist, var(--font-geist-sans, 'Geist')))), system-ui, sans-serif;
    font-weight: 400;
    font-size: var(--lf-fs,14px);
    letter-spacing: normal;
    color: var(--gc-ink);
    caret-color: var(--gc-acc);
    -webkit-appearance: none;
    appearance: none;
    transition: box-shadow var(--gc-t-c) ease,background-size var(--gc-t-fil) cubic-bezier(.22,1,.36,1),background-color var(--gc-t-c) ease;
    display: block;
    min-height: var(--lf-min-h,96px);
    padding: 12px 14px;
    border-radius: calc(14px * var(--lumen-radius-k, 1));
    line-height: 1.55;
    resize: vertical;
    field-sizing: content;
  }
  .lumen-textarea::placeholder {
    color: var(--gc-ph);
    opacity: 1;
  }
  @media (hover:hover) {
    .lumen-textarea:hover:not(:disabled) {
      --lf-ring: var(--gc-wrH);
    }
  }
  .lumen-textarea:focus,.lumen-textarea[data-force="focus"] {
    --lf-ring: color-mix(in srgb, var(--gc-acc) 65%, transparent);
    --lf-halo: 0 0 0 4px color-mix(in srgb, var(--gc-acc) 12%, transparent);
    background-size: calc(100% - 28px) 1px;
  }
  .lumen-textarea[aria-invalid="true"] {
    --lf-ring: color-mix(in srgb, var(--gc-bad) 60%, transparent);
    --lf-halo: 0 0 0 4px color-mix(in srgb, var(--gc-bad) 8%, transparent);
    --lf-fil: var(--gc-bad);
    background-size: calc(100% - 28px) 1px;
    animation: lumen-shake-a calc(.38s * var(--gcp-k, 1)) cubic-bezier(.22,1,.36,1);
  }
  .lumen-textarea:disabled {
    --lf-ring: var(--gc-wr);
    --lf-bg: var(--gc-wellD);
    opacity: .5;
    cursor: not-allowed;
    -webkit-text-fill-color: var(--gc-ink);
  }
  .lumen-textarea:-webkit-autofill {
    -webkit-text-fill-color: var(--gc-ink);
    transition: background-color 100000s 0s;
  }
  @media (max-width: 699px) {
    .lumen-textarea {
      --lf-fs: 16px;
    }
  }
}
```

The lumen 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/lumen-foundation.json.