# Button Group (Lumen Halo): prompt.md (v1.0.0)

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

Lumen's pill buttons joined into one control, outer ends round and inner joins tight, with a text cell for labels and units. shadcn's Button Group, 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: `@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/lumen/button-group.tsx`.
- Registry dependencies, installed with it automatically: shadcn `utils` (cn), `lumen-separator`, `lumen-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: `ButtonGroup`, `ButtonGroupText`, `ButtonGroupSeparator`, 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-mono`, `--lumen-radius-k`. Never add Tailwind colour classes inside the component.

```tsx
import { ButtonGroup } from "@/components/ui/lumen/button-group";
```

## Parts

| Part | data-slot | What it is for |
|---|---|---|
| `ButtonGroup` | `button-group` | The group. |
| `ButtonGroupText` | `button-group-text` | A label or unit cell. |
| `ButtonGroupSeparator` | `button-group-separator` | A hairline between. |

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/button-group.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
- button group, split button, segmented buttons, toolbar group, shadcn button group, Lumen
- Related actions side by side: zoom in and out, a split button, a unit

### Not when
- Choosing one of several: use Toggle Group

## Mistakes
- Keep it to related actions

## Usage

```tsx
import { ButtonGroup } from "@/components/ui/lumen/button-group";
import { Button } from "@/components/ui/lumen/button";

<ButtonGroup>
  <Button variant="secondary">Export</Button>
  <Button variant="secondary" size="icon" aria-label="More">…</Button>
</ButtonGroup>
```

## Props

| Prop | Type | Default | What it does |
|---|---|---|---|
| `orientation` | `"horizontal" \| "vertical"` | `"horizontal"` | Across or down. |

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

## 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 | Between the buttons |

## Motion inventory

| Interaction | What moves |
|---|---|
| None | Each button keeps its own motion |

## Accessibility contract (preserve when editing)
- role=group; label it when the purpose isn't obvious

## Install

```bash
npx shadcn@latest add @beautiful-ui-pro/lumen-button-group
```

Pro item: needs the `@beautiful-ui-pro` registry in `components.json` and `BEAUTIFUL_UI_TOKEN` in `.env.local` (https://beautiful-ui.dev/account). Setup: https://beautiful-ui.dev/docs/pro. Your components.json `style` picks the build: radix-*, new-york and default get Radix, base-* gets Base UI.

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

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.