# Site footer

> A website footer with link columns and newsletter, a minimal layout, and a large fading Silicon mark.

A shadcn/ui block from the [@silicon-ui](https://ui.teamofsilicons.com/?utm_source=shadcn.exchange) registry, listed on [shadcn.exchange](https://shadcn.exchange/r/silicon-ui/site-footer).

- Page, with a live preview: https://shadcn.exchange/r/silicon-ui/site-footer
- Screenshot: https://abzjhwgwpdpz7ua5.public.blob.vercel-storage.com/shots/silicon-ui/site-footer-light-a80f22b994848094.png
- Registry item: https://ui.teamofsilicons.com/r/site-footer.json
- Categories: blocks
- Listed: 2026-10-17, source last changed 2026-10-17

## Install

```bash
npx shadcn@latest add https://shadcn.exchange/r/silicon-ui/site-footer.json
```

Run it in a project that has shadcn/ui set up. It adds the files below and installs what they depend on.

## Dependencies

- npm packages: `lucide-react`, `motion`
- Registry items: `https://ui.teamofsilicons.com/r/silicon-motion-tokens.json`, `https://ui.teamofsilicons.com/r/button.json`, `https://ui.teamofsilicons.com/r/segmented-control.json`

## Notes from the registry

Docs and live preview: https://ui.teamofsilicons.com/site-footer

## Files

### `registry/blocks/site-footer/site-footer.tsx`

```tsx
"use client";

import { forwardRef, useId, useLayoutEffect, useRef, useState } from "react";
import type { FormEvent, ReactNode } from "react";
import { AnimatePresence, motion, useReducedMotion } from "motion/react";
import { ArrowUpRight, Check } from "lucide-react";
import { Button } from "../../button/button";
import SegmentedControl from "../../segmented-control/segmented-control";
import { motionTokens } from "../../lib/motion-tokens";
import styles from "./site-footer.module.css";

export type SiteFooterVariant = "columns" | "minimal" | "logo";

export interface SiteFooterLink {
  label: string;
  href?: string;
  /** Opens in a new tab and shows an outward arrow. */
  external?: boolean;
}

export interface SiteFooterColumn {
  title: string;
  links: SiteFooterLink[];
}

export interface SiteFooterNewsletter {
  title?: string;
  description?: string;
  placeholder?: string;
  /** Called with a valid address. Throw or reject to show an error; resolve to show the subscribed state. */
  onSubscribe?: (email: string) => void | Promise<void>;
}

export interface SiteFooterProps {
  /** `columns` pairs a newsletter with link columns, `minimal` is one quiet row, `logo` ends in a large fading Silicon mark. */
  variant?: SiteFooterVariant;
  brand?: { name: string; href?: string; mark?: ReactNode };
  /** One short line under the brand. */
  tagline?: string;
  columns?: SiteFooterColumn[];
  /** Links for the minimal variant. Defaults to the first link of each column. */
  links?: SiteFooterLink[];
  /** Small links beside the copyright, such as Privacy and Terms. */
  legal?: SiteFooterLink[];
  socials?: SiteFooterLink[];
  /** Newsletter signup. Pass null to hide it. */
  newsletter?: SiteFooterNewsletter | null;
  /** A system status link. Pass null to hide it. */
  status?: { label: string; tone?: "success" | "warning" | "danger"; href?: string } | null;
  /** Year in the copyright line. */
  year?: number;
  /** Called for every link that is pressed. Links without an href render as buttons and only call this. */
  onNavigate?: (link: SiteFooterLink) => void;
  className?: string;
}

type Bezier = [number, number, number, number];
const enter = [...motionTokens.ease.enter] as Bezier;

export const siteFooterExampleColumns: SiteFooterColumn[] = [
  { title: "Product", links: [{ label: "Components" }, { label: "Blocks" }, { label: "Templates" }, { label: "Pricing" }] },
  { title: "Resources", links: [{ label: "Documentation" }, { label: "Changelog" }, { label: "Guides" }, { label: "Figma kit", external: true }] },
  { title: "Company", links: [{ label: "About" }, { label: "Customers" }, { label: "Careers" }, { label: "Contact" }] },
];
const exampleLegal: SiteFooterLink[] = [{ label: "Privacy" }, { label: "Terms" }, { label: "Licenses" }];
const exampleSocials: SiteFooterLink[] = [{ label: "X", external: true }, { label: "GitHub", external: true }, { label: "LinkedIn", external: true }];
const EMAIL = /^[^\s@]+@[^\s@]+\.[^\s@]{2,}$/;

function FooterLink({ link, onNavigate, className }: { link: SiteFooterLink; onNavigate?: (link: SiteFooterLink) => void; className?: string }) {
  const content = <>{link.label}{link.external && <ArrowUpRight className={styles.external} size={13} strokeWidth={2} aria-hidden="true" />}</>;
  const onClick = () => onNavigate?.(link);
  if (link.href) return <a className={className ?? styles.link} href={link.href} onClick={onClick} {...(link.external ? { target: "_blank", rel: "noopener noreferrer" } : {})}>{content}</a>;
  return <button type="button" className={className ?? styles.link} onClick={onClick}>{content}</button>;
}

function SiliconMark({ className }: { className?: string }) {
  return <svg className={className} viewBox="40 40 204 204" fill="currentColor" aria-hidden="true">
    <rect x="49" y="117.9" width="47.7" height="47.7" /><rect x="70.2" y="70.2" width="47.7" height="47.7" /><rect x="70.2" y="165.6" width="47.7" height="47.7" /><rect x="90.06" y="141.75" width="72.78" height="72.78" transform="rotate(-45 90.06 141.75)" /><rect x="117.9" y="49" width="47.7" height="47.7" /><rect x="117.9" y="186.8" width="47.7" height="47.7" /><rect x="186.8" y="117.9" width="47.7" height="47.7" /><rect x="165.6" y="70.2" width="47.7" height="47.7" /><rect x="165.6" y="165.6" width="47.7" height="47.7" />
  </svg>;
}

/** Email signup that validates in place, keeps its width while the button morphs, and confirms without a toast. */
function Newsletter({ title, description, placeholder = "you@example.com", onSubscribe }: SiteFooterNewsletter) {
  const id = useId();
  const reduced = !!useReducedMotion();
  const [email, setEmail] = useState("");
  const [state, setState] = useState<"idle" | "loading" | "done">("idle");
  const [error, setError] = useState<string | null>(null);
  const [touched, setTouched] = useState(false);

  const validate = (value: string) => !value.trim() ? "Enter your email address" : EMAIL.test(value.trim()) ? null : "That email doesn't look right";

  async function submit(event: FormEvent) {
    event.preventDefault();
    if (state !== "idle") return;
    setTouched(true);
    const problem = validate(email);
    setError(problem);
    if (problem) return;
    setState("loading");
    try {
      await (onSubscribe ? onSubscribe(email.trim()) : new Promise(resolve => setTimeout(resolve, 900)));
      setState("done");
    } catch {
      setState("idle");
      setError("We couldn't subscribe you. Try again in a moment");
    }
  }

  const message = state === "done" ? `Check ${email.trim()} to confirm` : error ?? description;
  const tone = state === "done" ? "success" : error ? "error" : "hint";

  return <form className={styles.newsletter} onSubmit={submit} noValidate aria-labelledby={title ? `${id}-title` : undefined}>
    {title && <h2 id={`${id}-title`} className={styles.newsletterTitle}>{title}</h2>}
    <div className={styles.newsletterRow} data-invalid={error ? "" : undefined} data-done={state === "done" ? "" : undefined}>
      <label className={styles.srOnly} htmlFor={`${id}-email`}>Email address</label>
      <input
        id={`${id}-email`}
        className={styles.newsletterInput}
        type="email"
        inputMode="email"
        autoComplete="email"
        placeholder={placeholder}
        value={email}
        readOnly={state !== "idle"}
        aria-invalid={error ? true : undefined}
        aria-describedby={`${id}-message`}
        onChange={event => { setEmail(event.target.value); if (touched) setError(validate(event.target.value)); }}
        onBlur={() => { if (email) { setTouched(true); setError(validate(email)); } }}
      />
      <Button type="submit" size="sm" variant="primary" loading={state === "loading"} className={styles.newsletterButton} aria-disabled={state === "done" || undefined}>
        {state === "done" ? <><Check size={15} strokeWidth={2.25} aria-hidden="true" />Subscribed</> : "Subscribe"}
      </Button>
    </div>
    <div className={styles.messageSlot} id={`${id}-message`} aria-live="polite">
      <AnimatePresence initial={false} mode="popLayout">
        {message && <motion.p key={message} className={styles.message} data-tone={tone} role={tone === "error" ? "alert" : undefined}
          initial={reduced ? { opacity: 0 } : { opacity: 0, y: 4, filter: `blur(${motionTokens.blur.subtle}px)` }}
          animate={{ opacity: 1, y: 0, filter: "blur(0px)" }}
          exit={reduced ? { opacity: 0, transition: { duration: 0 } } : { opacity: 0, y: -4, filter: `blur(${motionTokens.blur.subtle}px)`, transition: { duration: motionTokens.duration.instant } }}
          transition={{ duration: reduced ? 0 : motionTokens.duration.standard, ease: enter }}>{message}</motion.p>}
      </AnimatePresence>
    </div>
  </form>;
}

/**
 * A website footer in three layouts: link columns with a newsletter signup, a single quiet row, and a closing
 * variant where the Silicon mark rises in, oversized and cropped by the bottom edge, fading into the page.
 */
export const SiteFooter = forwardRef<HTMLElement, SiteFooterProps>(function SiteFooter({
  variant = "columns",
  brand = { name: "Silicon" },
  tagline = "Interface components that move with intent.",
  columns = siteFooterExampleColumns,
  links,
  legal = exampleLegal,
  socials = exampleSocials,
  newsletter = { title: "Get the monthly release notes", description: "One email a month. Unsubscribe anytime." },
  status = { label: "All systems normal", tone: "success" },
  year = new Date().getFullYear(),
  onNavigate,
  className,
}, ref) {
  const reduced = !!useReducedMotion();
  const gradientId = useId().replace(/:/g, "");
  const brandNode = <FooterLink link={{ label: brand.name, href: brand.href }} onNavigate={onNavigate} className={styles.brand} />;
  const brandWithMark = <span className={styles.brandRow}>{brand.mark ?? <SiliconMark className={styles.brandMark} />}{brandNode}</span>;
  const statusNode = status && (status.href
    ? <a className={styles.status} href={status.href} data-tone={status.tone ?? "success"} onClick={() => onNavigate?.({ label: status.label, href: status.href })}><span className={styles.statusDot} aria-hidden="true" />{status.label}</a>
    : <button type="button" className={styles.status} data-tone={status.tone ?? "success"} onClick={() => onNavigate?.({ label: status.label })}><span className={styles.statusDot} aria-hidden="true" />{status.label}</button>);
  const socialNode = socials.length > 0 && <ul className={styles.inline} aria-label="Social">{socials.map(link => <li key={link.label}><FooterLink link={link} onNavigate={onNavigate} /></li>)}</ul>;
  const legalRow = <div className={styles.bottom}>
    <div className={styles.bottomStart}>
      <span className={styles.copyright}>© {year} {brand.name}</span>
      {legal.length > 0 && <ul className={styles.inline} aria-label="Legal">{legal.map(link => <li key={link.label}><FooterLink link={link} onNavigate={onNavigate} /></li>)}</ul>}
    </div>
    <div className={styles.bottomEnd}>{statusNode}{socialNode}</div>
  </div>;
  const columnNav = <nav className={styles.columns} aria-label="Footer">
    {columns.map(column => <div key={column.title} className={styles.column}>
      <h2>{column.title}</h2>
      <ul>{column.links.map(link => <li key={link.label}><FooterLink link={link} onNavigate={onNavigate} /></li>)}</ul>
    </div>)}
  </nav>;

  if (variant === "minimal") {
    const rowLinks = links ?? columns.map(column => column.links[0]).filter((link): link is SiteFooterLink => Boolean(link)).concat(legal.slice(0, 2));
    return <footer ref={ref} className={[styles.footer, styles.minimal, className].filter(Boolean).join(" ")}>
      <div className={styles.minimalRow}>
        {brandWithMark}
        <nav aria-label="Footer"><ul className={styles.inline}>{rowLinks.map(link => <li key={link.label}><FooterLink link={link} onNavigate={onNavigate} /></li>)}</ul></nav>
      </div>
      <div className={styles.minimalRow}>
        <span className={styles.copyright}>© {year} {brand.name}. {tagline}</span>
        <div className={styles.bottomEnd}>{statusNode}{socialNode}</div>
      </div>
    </footer>;
  }

  return <footer ref={ref} className={[styles.footer, variant === "logo" ? styles.logo : "", className].filter(Boolean).join(" ")}>
    <div className={styles.top}>
      <div className={styles.intro}>
        {brandWithMark}
        {tagline && <p className={styles.tagline}>{tagline}</p>}
        {newsletter && variant === "columns" && <Newsletter {...newsletter} />}
      </div>
      {columnNav}
    </div>
    {legalRow}
    {variant === "logo" && <motion.div className={styles.markStage} aria-hidden="true"
      initial={reduced ? false : { opacity: 0, y: 40 }}
      whileInView={{ opacity: 1, y: 0 }}
      viewport={{ once: true, amount: .3 }}
      transition={{ duration: reduced ? 0 : .9, ease: enter }}>
      {/* The top of the arch, drawn oversized and cropped by its viewBox, in the brand gradient and fading toward the bottom edge. */}
      <svg className={styles.bigMark} viewBox="0 3.5 64 30" fill="none" strokeWidth="3.4" strokeLinecap="round" strokeLinejoin="round" preserveAspectRatio="xMidYMin meet">
        <defs>
          <linearGradient id={gradientId} x1="0" y1="0" x2="1" y2="0">
            <stop offset="0" style={{ stopColor: "var(--silicon-gradient-from)" }} />
            <stop offset="1" style={{ stopColor: "var(--silicon-gradient-to)" }} />
          </linearGradient>
        </defs>
        <g stroke={`url(#${gradientId})`}>
          <path d="M9 48V29C9 15 19 7 32 7s23 8 23 22v19" />
          <path d="M20 48V31c0-8 5-13 12-13s12 5 12 13v17" />
          <path d="M32 38v10" />
        </g>
      </svg>
    </motion.div>}
  </footer>;
});

SiteFooter.displayName = "SiteFooter";

const variantOptions = [{ value: "columns", label: "Columns" }, { value: "minimal", label: "Minimal" }, { value: "logo", label: "Logo" }];

/** Preview: the footer with a switch between its three layouts and a note of the last link pressed. */
export function SiteFooterBlock({ variant: initial = "columns" }: { variant?: SiteFooterVariant }) {
  const [variant, setVariant] = useState<SiteFooterVariant>(initial);
  const [last, setLast] = useState<string | null>(null);
  const reduced = !!useReducedMotion();
  const contentRef = useRef<HTMLDivElement>(null);
  const [height, setHeight] = useState<number | null>(null);
  // The frame springs between layout heights instead of snapping; the new layout fades in where it sits.
  useLayoutEffect(() => {
    const node = contentRef.current;
    if (!node) return;
    setHeight(node.offsetHeight);
    if (typeof ResizeObserver === "undefined") return;
    const observer = new ResizeObserver(() => setHeight(node.offsetHeight));
    observer.observe(node);
    return () => observer.disconnect();
  }, [variant]);
  return <div className={styles.preview}>
    <SegmentedControl label="Footer layout" options={variantOptions} value={variant} onValueChange={value => setVariant(value as SiteFooterVariant)} />
    <div className={styles.frame}>
      <motion.div className={styles.frameBody} initial={false} animate={{ height: height ?? "auto" }} transition={reduced ? { duration: 0 } : motionTokens.spring.smooth}>
        <motion.div ref={contentRef} key={variant} initial={reduced ? false : { opacity: 0 }} animate={{ opacity: 1 }} transition={{ duration: motionTokens.duration.standard, ease: enter }}>
          <SiteFooter variant={variant} onNavigate={link => setLast(link.label)} />
        </motion.div>
      </motion.div>
    </div>
    <p className={styles.srOnly} aria-live="polite">{last ? `Opened ${last}` : ""}</p>
  </div>;
}

export default SiteFooterBlock;
```

### `registry/blocks/site-footer/site-footer.module.css`

```css
.footer { --footer-pad: var(--space-section); position: relative; container: site-footer / inline-size; overflow: hidden; border-top: 1px solid var(--border); padding: var(--space-page) var(--footer-pad) var(--space-section); background: var(--background); color: var(--foreground); font-family: var(--font-body); letter-spacing: var(--tracking-body); }
.srOnly { position: absolute; width: 1px; height: 1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap; }

.top { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.25fr); gap: var(--space-page); }
.intro { display: grid; align-content: start; gap: var(--space-group); min-width: 0; }
.brandRow { display: inline-flex; align-items: center; gap: var(--space-related); }
.brandMark { width: 22px; height: 22px; flex: none; color: var(--foreground); }
.brand { border: 0; padding: 0; background: none; color: var(--foreground); font: inherit; font-size: var(--text-base); font-weight: 500; text-decoration: none; cursor: pointer; }
.tagline { max-width: 320px; margin: 0; color: var(--text-secondary); font-size: var(--text-sm); line-height: var(--leading-body); }

.columns { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: var(--space-section); }
.column h2 { margin: 0 0 var(--space-group); font-size: var(--text-sm); font-weight: 500; }
.column ul, .inline { margin: 0; padding: 0; list-style: none; }
.column ul { display: grid; gap: var(--space-related); }
.link { display: inline-flex; align-items: center; gap: var(--space-tight); border: 0; padding: var(--space-hair) 0; background: none; color: var(--text-secondary); font: inherit; font-size: var(--text-sm); text-align: left; text-decoration: none; cursor: pointer; transition: color var(--duration-fast) var(--ease-standard); }
.link:active, .link:focus-visible { color: var(--foreground); }
.external { color: var(--text-muted); transition: transform var(--duration-fast) var(--ease-standard); }
@media (hover: hover) and (pointer: fine) {
  .link:hover { color: var(--foreground); }
  .link:hover .external { transform: translate(1px, -1px); }
}

/* Newsletter: input and button share one shell; the shell carries validation state with its border only. */
.newsletter { display: grid; gap: var(--space-related); max-width: 400px; margin-top: var(--space-comfort); }
.newsletterTitle { margin: 0; font-size: var(--text-sm); font-weight: 500; }
.newsletterRow { display: flex; height: var(--control-height-md); align-items: center; gap: var(--space-related); border: 1px solid var(--border); border-radius: var(--radius-control); corner-shape: var(--corner-shape); padding: var(--space-tight) var(--space-tight) var(--space-tight) var(--space-inset); background: var(--surface); transition: border-color var(--duration-fast) var(--ease-standard); }
.newsletterRow:focus-within { border-color: var(--border-strong); }
.newsletterRow[data-invalid] { border-color: var(--danger); }
.newsletterInput { width: 100%; min-width: 0; flex: 1; border: 0; padding: 0; background: none; color: var(--foreground); font: inherit; font-size: var(--text-sm); }
.newsletterInput::placeholder { color: var(--text-muted); }
.newsletterRow[data-done] .newsletterInput { color: var(--text-secondary); }
.newsletterButton { flex: none; border-radius: calc(var(--radius-control) - var(--space-tight)); corner-shape: var(--corner-shape); }
.messageSlot { position: relative; min-height: 20px; }
.message { margin: 0; color: var(--text-muted); font-size: var(--text-xs); line-height: 20px; }
.message[data-tone="error"] { color: var(--danger); }
.message[data-tone="success"] { color: var(--success); }

.bottom { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: var(--space-group) var(--space-section); margin-top: var(--space-page); border-top: 1px solid var(--border-subtle); padding-top: var(--space-comfort); }
.bottomStart, .bottomEnd { display: flex; flex-wrap: wrap; align-items: center; gap: var(--space-related) var(--space-comfort); }
.inline { display: flex; flex-wrap: wrap; align-items: center; gap: var(--space-tight) var(--space-inset); }
.copyright { color: var(--text-muted); font-size: var(--text-sm); }
.status { display: inline-flex; align-items: center; gap: var(--space-related); border: 0; padding: var(--space-hair) 0; background: none; color: var(--text-secondary); font: inherit; font-size: var(--text-sm); text-decoration: none; cursor: pointer; }
.statusDot { --tone: var(--success); width: 7px; height: 7px; border-radius: 50%; corner-shape: round; background: var(--tone); box-shadow: 0 0 0 3px color-mix(in oklab, var(--tone) 18%, transparent); }
.status[data-tone="warning"] .statusDot { --tone: var(--warning); }
.status[data-tone="danger"] .statusDot { --tone: var(--danger); }
@media (hover: hover) and (pointer: fine) { .status:hover { color: var(--foreground); } }

/* Minimal: two quiet rows. */
.minimal { padding-block: var(--space-block) var(--space-section); }
.minimalRow { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: var(--space-group) var(--space-section); }
.minimalRow + .minimalRow { margin-top: var(--space-section); border-top: 1px solid var(--border-subtle); padding-top: var(--space-comfort); }

/* Logo: the arch closes the page, cropped by the bottom edge and fading out in the brand gradient. */
.logo { padding-bottom: 0; }
.markStage { margin: var(--space-page) calc(var(--footer-pad) * -1) 0; -webkit-mask-image: linear-gradient(to bottom, #000 18%, transparent 96%); mask-image: linear-gradient(to bottom, #000 18%, transparent 96%); pointer-events: none; }
.bigMark { display: block; width: 100%; height: auto; }

@container site-footer (max-width: 760px) {
  .top { grid-template-columns: minmax(0, 1fr); gap: var(--space-page); }
}
@container site-footer (max-width: 520px) {
  .columns { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--space-block) var(--space-inset); }
  .newsletter { max-width: none; }
  .bottom { flex-direction: column; align-items: flex-start; }
}

.preview { display: grid; width: 100%; justify-items: center; gap: var(--space-inset); }
.frame { width: 100%; overflow: hidden; border: 1px solid var(--border); border-radius: var(--radius-control); corner-shape: var(--corner-shape); background: var(--background); }
.frameBody { overflow: hidden; }
.frame .footer { border-top: 0; }
.previewNote { min-height: 20px; margin: 0; color: var(--text-muted); font-size: var(--text-xs); }

@media (prefers-reduced-motion: reduce) {
  .link, .external, .newsletterRow { transition: none; }
}
```

### `registry/components/segmented-control/segmented-control.tsx`

```tsx
"use client";

import { useEffect, useId, useLayoutEffect, useRef, type KeyboardEvent, type ReactNode } from "react";
import { LayoutGroup, motion, useReducedMotion } from "motion/react";
import { motionTokens } from "../lib/motion-tokens";
import styles from "./segmented-control.module.css";

export interface Segment { value: string; label: string; /** Optional content after the label, such as a badge. */ accessory?: ReactNode; }
export interface SegmentedControlProps {
  options: Segment[];
  value: string;
  onValueChange: (value: string) => void;
  label?: string;
  /** Called when the pointer or focus reaches an option, before it is chosen. Use it to start loading what that option shows. */
  onOptionIntent?: (value: string) => void;
  /** `sm` (default) or `xs`, a compact 24px control for dense UI such as an Edit/Read toggle in a toolbar. */
  size?: "sm" | "xs";
  className?: string;
}

export default function SegmentedControl({ options, value, onValueChange, label, onOptionIntent, size = "sm", className }: SegmentedControlProps) {
  const id = useId();
  const reduced = useReducedMotion();
  const track = useRef<HTMLDivElement>(null);

  // When the options are wider than the container, the track scrolls inside itself. Edges fade only on the side with more to see.
  useLayoutEffect(() => {
    const node = track.current;
    if (!node) return;
    const edges = () => {
      const rest = node.scrollWidth - node.clientWidth - node.scrollLeft;
      node.toggleAttribute("data-fade-start", node.scrollLeft > 1);
      node.toggleAttribute("data-fade-end", rest > 1);
    };
    edges();
    node.addEventListener("scroll", edges, { passive: true });
    const observer = typeof ResizeObserver === "undefined" ? null : new ResizeObserver(edges);
    observer?.observe(node);
    return () => { node.removeEventListener("scroll", edges); observer?.disconnect(); };
  }, [options.length]);

  // The selected option is always scrolled fully into view, with a little room so it clears the fade.
  const first = useRef(true);
  useEffect(() => {
    const node = track.current;
    const button = node?.querySelector<HTMLElement>('[aria-pressed="true"]');
    if (!node || !button || node.scrollWidth <= node.clientWidth) { first.current = false; return; }
    const room = 20, start = button.offsetLeft - room, end = button.offsetLeft + button.offsetWidth + room - node.clientWidth;
    const left = node.scrollLeft > start ? start : node.scrollLeft < end ? end : node.scrollLeft;
    if (left !== node.scrollLeft) node.scrollTo({ left: Math.max(0, left), behavior: first.current || reduced ? "auto" : "smooth" });
    first.current = false;
  }, [value, reduced]);

  // Arrow keys, Home and End move the selection like a tab list; only the selected option is a tab stop.
  const selectedIndex = Math.max(0, options.findIndex(option => option.value === value));
  const onKeyDown = (event: KeyboardEvent<HTMLButtonElement>) => {
    const last = options.length - 1;
    const target = event.key === "ArrowRight" || event.key === "ArrowDown" ? (selectedIndex === last ? 0 : selectedIndex + 1)
      : event.key === "ArrowLeft" || event.key === "ArrowUp" ? (selectedIndex === 0 ? last : selectedIndex - 1)
        : event.key === "Home" ? 0 : event.key === "End" ? last : -1;
    if (target < 0 || !options[target]) return;
    event.preventDefault();
    onValueChange(options[target].value);
    track.current?.querySelector<HTMLElement>(`[data-value="${CSS.escape(options[target].value)}"]`)?.focus({ preventScroll: true });
  };

  return <div className={`${styles.root} ${className ?? ""}`} role="group" aria-label={label} data-size={size}>
    <LayoutGroup id={id}><motion.div ref={track} layoutScroll className={styles.track}>
      {options.map((option, index) => <button key={option.value} id={`${id}-${option.value}`} className={styles.button} type="button" data-value={option.value} aria-pressed={value === option.value} tabIndex={index === selectedIndex ? 0 : -1} onClick={() => onValueChange(option.value)} onKeyDown={onKeyDown} onPointerEnter={onOptionIntent ? () => onOptionIntent(option.value) : undefined} onFocus={onOptionIntent ? () => onOptionIntent(option.value) : undefined}>
        {value === option.value && <motion.span className={styles.selection} layoutId="selection" layoutDependency={value} transition={reduced ? { duration: 0 } : motionTokens.spring.morph} aria-hidden="true" />}
        <span className={styles.label}>{option.label}{option.accessory}</span>
      </button>)}
    </motion.div></LayoutGroup>
  </div>;
}
```

### `registry/components/segmented-control/segmented-control.module.css`

```css
/* The frame can shrink below its content inside flex and grid parents; the track then scrolls inside it. */
.root { display: inline-flex; min-width: 0; max-width: 100%; flex-shrink: 1; border: 1px solid var(--border); border-radius: var(--radius-control); background: var(--surface-muted); }
/* The track owns the stacking context so the gliding highlight passes under every label, not over earlier ones. */
.track { --fade-start: 0px; --fade-end: 0px; isolation: isolate; display: flex; min-width: 0; gap: var(--space-hair); overflow-x: auto; overscroll-behavior-x: contain; padding: var(--space-tight); border-radius: inherit; corner-shape: inherit; scrollbar-width: none; -webkit-mask-image: linear-gradient(to right, transparent, #000 var(--fade-start), #000 calc(100% - var(--fade-end)), transparent); mask-image: linear-gradient(to right, transparent, #000 var(--fade-start), #000 calc(100% - var(--fade-end)), transparent); }
.track::-webkit-scrollbar { display: none; }
.track[data-fade-start] { --fade-start: 20px; }
.track[data-fade-end] { --fade-end: 20px; }
/* Items never scale or change weight; only the highlight travels and the label color follows it. */
.button { position: relative; flex: 0 0 auto; min-height: var(--control-height-sm); border: 0; border-radius: calc(var(--radius-control) - var(--space-tight)); padding: 0 var(--space-group); background: transparent; color: var(--text-muted); font: inherit; font-size: var(--text-sm); font-weight: 500; white-space: nowrap; cursor: pointer; -webkit-tap-highlight-color: transparent; transition: color var(--duration-fast) var(--ease-standard); }
@media (hover: hover) and (pointer: fine) { .button:hover { color: var(--foreground); } }
.button:active, .button[aria-pressed="true"] { color: var(--foreground); }
.selection { position: absolute; z-index: -1; inset: 0; border: 1px solid var(--border); border-radius: inherit; corner-shape: inherit; background: var(--surface); box-shadow: var(--shadow-resting); }
.label { position: relative; z-index: 1; display: inline-flex; align-items: center; gap: var(--space-related); }
/* Compact: 24px segments in a thinner track, at the small type step. */
.root[data-size="xs"] .track { padding: var(--space-hair); }
.root[data-size="xs"] .button { min-height: var(--control-height-xs); padding: 0 var(--space-related); font-size: var(--text-xs); }
@media (max-width: 380px) { .button { padding: 0 var(--space-group); } }
@media (prefers-reduced-motion: reduce) { .button { transition: none; } }
```

### `registry/components/button/button.tsx`

```tsx
"use client";

import { forwardRef, isValidElement, useCallback, useEffect, useLayoutEffect, useRef } from "react";
import type { ButtonHTMLAttributes, ReactNode, Ref, RefObject } from "react";
import { AnimatePresence, animate, motion, useIsPresent, useMotionValue, useReducedMotion } from "motion/react";
import type { TargetAndTransition, Variants } from "motion/react";
import { motionTokens } from "../lib/motion-tokens";
import styles from "./button.module.css";

/** `soft` is filled and borderless, for controls in a bar (experimental). */
export type ButtonVariant = "primary" | "secondary" | "ghost" | "danger" | "soft";
/** `xs` (24px) is for dense UI such as tree rows and toolbars, usually icon-only with an aria-label. */
export type ButtonSize = "xs" | "sm" | "md" | "lg";

export interface ButtonProps extends Omit<ButtonHTMLAttributes<HTMLButtonElement>, "onDrag" | "onDragEnd" | "onDragStart" | "onAnimationStart"> {
  /** The look: `primary` (default) for the main action, `secondary` bordered, `ghost` quiet, `danger` destructive, `soft` filled for bars. */
  variant?: ButtonVariant;
  /** Height: `xs` 24px, `sm` 36px, `md` 44px (default), `lg` 50px. */
  size?: ButtonSize;
  /** Shows a spinner in place of the label and sets aria-busy, keeping the button's width. */
  loading?: boolean;
}

/** Icon buttons press a little deeper, wide buttons a little less, so every size reads as the same push. */
const pressVariants: Variants = {
  pressed: (button: RefObject<HTMLButtonElement | null>) => {
    const width = button.current?.offsetWidth ?? 0;
    return { scale: width > 220 ? .985 : width && width <= 48 ? .96 : .97, transition: { duration: motionTokens.duration.instant, ease: [...motionTokens.ease.standard] } };
  },
};

const rest: TargetAndTransition = { opacity: 1, y: 0, scale: 1, filter: "blur(0px)" };
/** Text rises about .3em out of a soft blur; the outgoing label lifts away a little faster. */
const textIn: TargetAndTransition = { opacity: 0, y: 4, filter: `blur(${motionTokens.blur.soft}px)` };
const textOut: TargetAndTransition = { opacity: 0, y: -3, filter: `blur(${motionTokens.blur.soft}px)`, transition: { duration: motionTokens.duration.fast, ease: [...motionTokens.ease.standard] } };
const iconIn: TargetAndTransition = { opacity: 0, scale: .6, filter: `blur(${motionTokens.blur.subtle}px)` };
const iconOut: TargetAndTransition = { opacity: 0, scale: .6, filter: `blur(${motionTokens.blur.subtle}px)`, transition: { duration: motionTokens.duration.fast, ease: [...motionTokens.ease.standard] } };
const fadeIn: TargetAndTransition = { ...rest, opacity: 0 };
const fadeOut: TargetAndTransition = { opacity: 0, transition: { duration: motionTokens.duration.instant } };
/** Scale rides the spring; opacity and blur tween so blur never overshoots below zero. */
const iconEnter = { ...motionTokens.spring.snappy, opacity: { duration: motionTokens.duration.fast, ease: [...motionTokens.ease.enter] }, filter: { duration: motionTokens.duration.fast, ease: [...motionTokens.ease.enter] } } as const;

/** A key for the label content: text plus element names, so a new label or icon crossfades while prop-only updates stay in place. */
function labelKey(node: ReactNode): string {
  if (node == null || typeof node === "boolean") return "";
  if (typeof node === "string" || typeof node === "number" || typeof node === "bigint") return String(node);
  if (Array.isArray(node)) return node.map(labelKey).join("");
  if (!isValidElement(node)) return "";
  const type = node.type as string | { displayName?: string; name?: string };
  return `<${typeof type === "string" ? type : type?.displayName ?? type?.name ?? ""}>${labelKey((node.props as { children?: ReactNode }).children)}`;
}

/** Springs the slot to the natural width of the incoming label when it changes, so a new label never snaps the button's size.
 *  The outgoing label is popped out of flow at once, so it never holds the old width. Other resizes (a late web font, a parent reflow) jump straight to the new width, so nothing wobbles on first paint. */
function useMorphWidth(content: RefObject<HTMLElement | null>, key: string, reduced: boolean) {
  const width = useMotionValue<number | "auto">("auto");
  const lastKey = useRef(key), armedUntil = useRef(0);
  useLayoutEffect(() => {
    if (lastKey.current === key) return;
    lastKey.current = key;
    armedUntil.current = performance.now() + 700;
  }, [key]);
  useEffect(() => {
    const node = content.current, slot = node?.parentElement;
    if (!node || !slot || typeof ResizeObserver === "undefined") return;
    let measured = false;
    const observer = new ResizeObserver(([entry]) => {
      if (!entry) return;
      const next = entry.contentRect.width;
      if (!next || !measured || reduced || performance.now() > armedUntil.current) { measured = next > 0; width.jump(next || "auto"); delete slot.dataset.morphing; return; }
      slot.dataset.morphing = "";
      animate(width, next, { ...motionTokens.spring.morph, onComplete: () => { delete slot.dataset.morphing; } });
    });
    observer.observe(node);
    return () => observer.disconnect();
  }, [content, reduced, width]);
  return width;
}

function LabelPhase({ children, icon, reduced, ref }: { children: ReactNode; icon: boolean; reduced: boolean; ref?: Ref<HTMLSpanElement> }) {
  const present = useIsPresent();
  return <motion.span ref={ref} className={styles.labelPhase} aria-hidden={present ? undefined : true} initial={reduced ? fadeIn : icon ? iconIn : textIn} animate={rest} exit={reduced ? fadeOut : icon ? iconOut : textOut} transition={reduced ? { duration: motionTokens.duration.instant } : icon ? iconEnter : { duration: motionTokens.duration.standard, ease: [...motionTokens.ease.enter] }}>{children}</motion.span>;
}

export const Button = forwardRef<HTMLButtonElement, ButtonProps>(function Button(
  { className, variant = "primary", size = "md", loading = false, disabled, children, onClick, ...props },
  ref,
) {
  const reduceMotion = useReducedMotion() ?? false;
  const buttonRef = useRef<HTMLButtonElement | null>(null);
  const contentRef = useRef<HTMLSpanElement>(null);
  const key = labelKey(children);
  const width = useMorphWidth(contentRef, key, reduceMotion);
  const setRefs = useCallback((node: HTMLButtonElement | null) => {
    buttonRef.current = node;
    if (typeof ref === "function") ref(node); else if (ref) ref.current = node;
  }, [ref]);
  // A trigger that anchors a menu, popover, or dialog keeps its rect still while pressed, so the layer never measures a scaled anchor.
  // Radix triggers (asChild) pass aria-haspopup or data-state through; the stylesheet repeats the guard.
  const popup = props["aria-haspopup"];
  const anchorsLayer = (popup !== undefined && popup !== false && popup !== "false") || props.role === "combobox" || (props as Record<string, unknown>)["data-state"] !== undefined;
  const inert = disabled || loading || props["aria-disabled"] === true || props["aria-disabled"] === "true";
  const classes = [styles.button, styles[variant], styles[size], className].filter(Boolean).join(" ");
  // An icon with no text: square at the compact size.
  const iconOnly = !/\S/.test(key.replace(/<[^>]*>/g, ""));

  return (
    <motion.button
      ref={setRefs}
      tabIndex={props.tabIndex ?? 0}
      className={classes}
      data-variant={variant}
      data-icon-only={iconOnly || undefined}
      disabled={disabled}
      aria-busy={loading || undefined}
      custom={buttonRef}
      variants={pressVariants}
      whileTap={reduceMotion || anchorsLayer || inert ? undefined : "pressed"}
      transition={motionTokens.spring.snappy}
      {...props}
      // Loading keeps the button focusable (a disabled button would drop keyboard focus mid-action) and swallows presses instead.
      aria-disabled={loading || props["aria-disabled"] || undefined}
      onClick={loading ? event => event.preventDefault() : onClick}
    >
      <AnimatePresence initial={false}>
        {loading ? <motion.span key="loader" className={styles.loader} aria-hidden="true" initial={reduceMotion ? { opacity: 0 } : { opacity: 0, scale: .6 }} animate={{ opacity: 1, scale: 1 }} exit={reduceMotion ? fadeOut : { ...iconOut, scale: .8 }} transition={reduceMotion ? { duration: motionTokens.duration.instant } : iconEnter}><span className={styles.spinner} /></motion.span> : null}
      </AnimatePresence>
      <motion.span className={[styles.labelSlot, loading ? styles.loadingLabel : ""].filter(Boolean).join(" ")} style={{ width }}>
        <span ref={contentRef} className={styles.labelContent}>
          <AnimatePresence mode="popLayout" initial={false}>
            <LabelPhase key={key} icon={!/\S/.test(key.replace(/<[^>]*>/g, ""))} reduced={reduceMotion}>{children}</LabelPhase>
          </AnimatePresence>
        </span>
      </motion.span>
    </motion.button>
  );
});

Button.displayName = "Button";

export default Button;
```

### `registry/components/button/button.module.css`

```css
/* Press scale is driven by Motion (whileTap) alone, so transform never gets a CSS transition here. */
.button { position: relative; display: inline-flex; min-height: var(--control-height-md); align-items: center; justify-content: center; gap: var(--space-related); border: 1px solid transparent; border-radius: var(--radius-control); corner-shape: var(--corner-shape); padding: 0 var(--space-inset); font: inherit; font-size: var(--text-sm); font-weight: 500; line-height: var(--leading-body); white-space: nowrap; cursor: pointer; -webkit-tap-highlight-color: transparent; transition: color var(--duration-fast) var(--ease-standard), background var(--duration-fast) var(--ease-standard), border-color var(--duration-fast) var(--ease-standard), opacity var(--duration-fast) var(--ease-standard), box-shadow var(--duration-fast) var(--ease-standard); }
.button:disabled { cursor: not-allowed; opacity: .52; }
.button[aria-busy="true"] { cursor: progress; }
/* Anchors of floating layers never scale: Radix opens on pointerdown and would measure a shrunken trigger. */
.button:is([aria-haspopup]:not([aria-haspopup="false"]), [data-state], [role="combobox"]) { transform: none !important; }
/* The slot's width follows the incoming label on a spring. The label stays centered and may overflow evenly while the slot catches up;
   the outgoing label pops out of flow against the slot itself, so it keeps its place instead of following the new content box. */
.labelSlot { position: relative; display: inline-flex; min-width: 0; align-items: center; justify-content: center; transition: opacity var(--duration-fast) var(--ease-standard); }
.labelSlot[data-morphing] { clip-path: inset(-50% calc(var(--space-group) * -1)); }
.labelContent { display: inline-flex; flex: none; align-items: center; }
.labelPhase { display: inline-flex; align-items: center; justify-content: center; gap: var(--space-related); white-space: nowrap; }
.labelPhase svg { flex: none; }
.primary { color: var(--primary-foreground); background: var(--primary); border-color: var(--primary); }
.secondary { color: var(--foreground); background: var(--surface); border-color: var(--border); }
.ghost { color: var(--text-secondary); background: transparent; border-color: transparent; }
.danger { color: var(--danger); background: var(--surface); border-color: var(--border); }
/* Filled and borderless, for controls that live in a bar (a search trigger, a toolbar, a switcher). Place it on --background or
   --surface; on a --surface-muted panel it has no fill to show. */
.soft { color: var(--foreground); background: var(--surface-muted); border-color: transparent; }
/* A disabled outlined button keeps its shape and fades only its label, so it still reads as a button that is off, not as plain text. */
.secondary:disabled, .danger:disabled { opacity: 1; color: var(--text-muted); background: var(--surface-muted); border-color: var(--border); }
.danger:disabled { color: color-mix(in oklab, var(--danger) 55%, var(--surface-muted)); }
.ghost:disabled, .soft:disabled { opacity: 1; color: var(--text-muted); }
@media (hover: hover) and (pointer: fine) {
  .primary:hover:not(:disabled) { opacity: .91; box-shadow: var(--shadow-resting); }
  .secondary:hover:not(:disabled) { background: var(--surface-muted); box-shadow: var(--shadow-resting); }
  .ghost:hover:not(:disabled) { color: var(--foreground); background: var(--surface-muted); }
  .danger:hover:not(:disabled) { border-color: var(--danger); background: var(--surface-muted); }
  .soft:hover:not(:disabled) { background: var(--surface-pressed); }
}
/* Color feedback on press, so touch and menu triggers (which never scale) still answer the finger. */
.primary:active:not(:disabled) { opacity: .84; }
.secondary:active:not(:disabled), .ghost:active:not(:disabled) { color: var(--foreground); background: var(--surface-muted); }
.danger:active:not(:disabled) { border-color: var(--danger); background: var(--surface-muted); }
.soft:active:not(:disabled) { background: var(--surface-pressed); }
.xs { min-height: var(--control-height-xs); gap: var(--space-tight); padding-inline: var(--space-related); font-size: var(--text-xs); }
/* A compact icon-only button is a square, with the icon at its usual 16px. */
.xs[data-icon-only] { min-width: var(--control-height-xs); padding-inline: 0; }
.xs svg { width: 16px; height: 16px; }
.sm { min-height: var(--control-height-sm); padding-inline: var(--space-group); font-size: var(--text-sm); }
.md { min-height: var(--control-height-md); }
.lg { min-height: var(--control-height-lg); padding-inline: var(--space-comfort); font-size: var(--text-sm); }
.loader { position: absolute; left: 50%; top: 50%; display: grid; width: var(--space-inset); height: var(--space-inset); margin: calc(var(--space-inset) / -2); }
.spinner { border: 1.5px solid currentColor; border-right-color: transparent; border-radius: 50%; corner-shape: round; animation: spin .7s linear infinite; }
.loadingLabel { opacity: 0; }
@keyframes spin { to { transform: rotate(360deg); } }
@media (prefers-reduced-motion: reduce) { .button { transition: none; } .labelSlot { transition: opacity var(--duration-instant) linear; } .spinner { animation-duration: .01ms; animation-iteration-count: 1; } }
```