Action bar

// Copyright (c) 2026 Bruno Delorence. MIT License.'use client';import {  useEffect,  useEffectEvent,  useId,  useLayoutEffect,  useRef,  useState,  type CSSProperties,  type FocusEvent,  type KeyboardEvent,  type ReactNode,  type Ref,} from 'react';import { DemoPointer, runDemo } from './demo-pointer';import {  AlertIcon,  CheckIcon,  ChevronUpIcon,  DuplicateIcon,  ExportIcon,

/* Action bar (action-bar.tsx). A sheet with four floating bars stacked in its middle, and the   bars' edges drawn as dashed guides across it. In a stage narrower than the bulk bar, the bulk   bar keeps its icons only and the messages wrap.   Colours. Every colour is a token on .root, light-dark(light, dark): the component takes the   color-scheme it inherits from the page (light unless the page says otherwise), or the one its   colorScheme prop sets (data-color-scheme). By day the bars are white, with a hairline and a soft   shadow, on a light grey sheet; at night they are near-black, with a dark rim and a faint light   line inside it, on a dark grey sheet.   Memory and layout. The stage is one layout boundary of a known size. What moves is a transform,   an opacity or a clip-path on a box of a fixed size: the plate behind the bulk bar never changes   size (a clip-path cuts it to the bar's width), the toasts move as a whole, the digits slide in   their windows. The icons are drawings that never change; the bars fade the boxes around them. */.root {  /* The sheet, its edge, and the dashed guides across it. The sheet is a step off the bars: a     light grey under white bars by day, a dark grey above near-black ones at night. */  --surface: #f5f5f7;  --edge: rgb(0 0 0 / 0.06);  --guide: #dbdbe0;  /* The bars' shadow on the sheet: close, then softer further down. */  --shadow: rgb(0 0 0 / 0.08);  --shadow-far: rgb(0 0 0 / 0.07);

import styles from './action-bar.module.css';/* * A number whose digits roll to their new values, like an odometer. Each digit is a column of * 0 to 9 seen through a window one digit tall; a change slides the column (a transform, on a * spring set in the stylesheet). The digits are drawn with tabular figures, so the number keeps * its width while they roll. Screen readers get the plain number from the bar's own label. */const DIGITS = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9'];export function RollingNumber({ value }: { value: number }) {  const digits = String(Math.max(0, Math.round(value))).split('');  return (    <span className={styles.rolling} aria-hidden="true">      {digits.map((digit, i) => (        // Keyed from the right, so a number that grows a digit keeps its ones in place.        <span key={digits.length - i} className={styles.digit}>          <span className={styles.digitSize}>0</span>          <span            className={styles.column}            style={{ transform: `translateY(${-Number(digit) * 10}%)` }}          >            {DIGITS.map((d) => (

import type { ReactNode } from 'react';/* * The bars' icons: 16 × 16 line drawings with a 1.5 stroke and round ends, in the colour of the * text around them. They never change once drawn (a style change inside an SVG lays it out * again): to switch one for another, the bar fades the HTML boxes around them. */function Icon({ children }: { children: ReactNode }) {  return (    <svg      viewBox="0.6 0.6 14.8 14.8"      width="16"      height="16"      fill="none"      stroke="currentColor"      strokeWidth="1.5"      strokeLinecap="round"      strokeLinejoin="round"      aria-hidden="true"    >      {children}    </svg>  );

/* * Springs as CSS easings. A spring pulls a value to its target and lets it settle: fast at first, * then slowing down, overshooting a little and coming back if it is bouncy. CSS `linear()` draws * any curve through a list of points, so the spring's motion is sampled once, and the same curve * serves CSS transitions and the Web Animations API. */export type Spring = {  /** The curve, as a CSS `linear()` easing. */  easing: string;  /** How long it takes to settle, in ms: the duration to play the curve over. */  duration: number;};/** Points sampled along the curve: plenty for a smooth motion. */const SAMPLES = 40;/** * A spring that covers most of the distance in about `response` ms. With a `bounce` of 0 it * settles without overshooting; at 0.3 it overshoots by about 5% and comes back. */export function spring(bounce: number, response: number): Spring {  // The damping ratio (1: no overshoot) and the natural frequency, in radians per second.  const damping = 1 - bounce;

'use client';import type { CSSProperties, Ref } from 'react';/* * The demo's pointer, and the steps that move it. A demo is a script of awaited steps: wait, * glide the pointer onto a control and press it, calling the component's own handler as a click * would. Stopping the demo (the reader takes over, or it scrolls away) ends the step in progress * at once: its promise rejects, which ends the script right there, and the pointer fades out. * * Nothing the pointer does needs a layout: it glides by an animation the compositor plays, and * the press scales a box that keeps a transform at rest (a box that gains or loses one is laid * out again). The arrow is an SVG drawing whose style never changes, inside HTML boxes. */export type Point = { x: number; y: number };export type Demo = {  /** Resolves after `ms`. */  wait: (ms: number) => Promise<void>;  /** Glides the pointer onto `target`: its middle, or a point given as shares of its size. */  moveTo: (target: Element | null | undefined, at?: Point) => Promise<void>;  /** Presses and lets go; `action` runs as the pointer goes down. */  press: (action: () => void) => Promise<void>;

'use client';import { useCallback, useEffect, useRef, useState } from 'react';/* * When a demo may play on its own: while part of it is on screen and the tab is visible, never * under reduced motion, and not while the reader is using it. `take()` hands it to the reader; it * takes back over `idle` ms after their last input. */export function useAutoplay<T extends HTMLElement>(idle = 6000) {  const ref = useRef<T>(null);  const [visible, setVisible] = useState(false);  const [reduced, setReduced] = useState(true);  const [taken, setTaken] = useState(false);  const timer = useRef(0);  useEffect(() => {    const element = ref.current;    if (!element) return;    let onScreen = false;    const update = () => setVisible(onScreen && !document.hidden);    const observer = new IntersectionObserver(      ([entry]) => {        onScreen = entry.isIntersecting;