# Annotation Arrow

> A note that draws a hand-drawn arrow to the element it points at, picked by a CSS selector. The curve avoids both boxes and redraws when the layout moves.

SVG & Drawing · svg, arrow, annotation, hand-drawn, callout, doodle, hero, pointer · HTML, CSS, vanilla JS · no dependencies · updated 2026-11-04
Demo: https://kodza.dev/components/annotation-arrow/
Source on GitHub: https://github.com/kodza-dev/kodza/tree/main/components/annotation-arrow

## Files

The code below, served as files: byte for byte what the Kodza site copies (the CSS includes its theme guard).

- [`kodza-annotation-arrow.css`](https://kodza.dev/registry/annotation-arrow/kodza-annotation-arrow.css) · 5.3 KB
- [`kodza-annotation-arrow.js`](https://kodza.dev/registry/annotation-arrow/kodza-annotation-arrow.js) · 22.2 KB
- [`kodza-annotation-arrow.html`](https://kodza.dev/registry/annotation-arrow/kodza-annotation-arrow.html) · 0.1 KB · the markup, to adapt and paste into your page

**Can you run shell commands? Download the CSS and the JS, don't retype them.** Retyping costs thousands of tokens and can drop or change lines of the CSS. Put the files where your stack expects them (Use it says where: change the `-o` paths):

```bash
curl -fsSL --create-dirs -o kodza/kodza-annotation-arrow.css https://kodza.dev/registry/annotation-arrow/kodza-annotation-arrow.css
curl -fsSL --create-dirs -o kodza/kodza-annotation-arrow.js https://kodza.dev/registry/annotation-arrow/kodza-annotation-arrow.js
```

Then load the files from your page as Use it shows, instead of pasting the content. The HTML is the part you adapt (text, links, modifiers): paste it from the Code section. Copy the CSS and the JS from the Code section only if you can't run commands, exactly as they are. (Windows PowerShell: `curl.exe`.)

## API

- Root: `.kodza-annotation-arrow`
- Variables (set them on the root element itself: it declares its own defaults):
  - `--kz-annotation-arrow-ink: #0a0a0a` — the note and its line
  - `--kz-annotation-arrow-stroke: 1.75px` — the line's thickness
  - `--kz-annotation-arrow-width: 240px` — the note's widest, before it wraps
- Attributes:
  - `data-mark`
  - `data-target` (e.g. `.hero-cta`)
- Lifecycle: `kodza:init` / `kodza:destroy` on `document`, with `{ detail: { root } }` to target a container.

## Dark mode

The values Kodza uses on a dark background (`#0a0a0a`). For a page that follows the system theme, add them after the component's CSS:

```css
@media (prefers-color-scheme: dark) {
  .kodza-annotation-arrow {
    --kz-annotation-arrow-ink: #f2f2f0;
  }
}
```

A site with its own theme switch puts the same rules under its dark selector instead (`[data-theme="dark"] .kodza-annotation-arrow { … }`); a single dark section, under that section's class.

## Use it

### Plain HTML page

- CSS: `kodza/kodza-annotation-arrow.css` next to the page (the Files commands as they are), linked in `<head>`: `<link rel="stylesheet" href="kodza/kodza-annotation-arrow.css">`. Without a shell, paste it in a `<style>` in `<head>` instead. It only touches `kodza-` classes.
- HTML: where the component goes. Paste it as many times as you need: instances never interfere.
- JS: `kodza/kodza-annotation-arrow.js`, loaded with `<script src="kodza/kodza-annotation-arrow.js" defer></script>` in `<head>`. Without a shell, paste it in a `<script>` before `</body>` (or in `<head>`: it waits for the page). One copy per page, whatever the number of instances.
- Restyle with the `--kz-…` variables, set on the component's root element itself (the root declares its own defaults, so a value on an ancestor is ignored), and with the modifiers / attributes listed under API.
- Font: it takes the page's own. A site with its own type sets it once for every Kodza component, on `:root`, never by editing the CSS (unset, nothing changes): `--kz-font-label`, the face of the small labels (meta, captions, counters, hints, footer links, button labels); `--kz-font-label-size`, their size, one for all of them (`11px`…); `--kz-font-label-weight`, their weight; `--kz-font-label-tracking`, their letter-spacing; `--kz-font-label-case`, their case (`uppercase`…; code and units keep theirs); `--kz-font-label-leading`, their line-height (`1.45`…; buttons, pills and keys keep their box); `--kz-font-mono`, the monospace face (code, labels, counters). The Kodza look is Geist: `<link rel="stylesheet" href="https://fonts.googleapis.com/css2?family=Geist:wght@400;500;600;700&family=Geist+Mono:wght@400;500&display=swap">`.
- Motion: a site sets its pace once for every Kodza component, on `:root`, never by editing the CSS or the JS: `--kz-motion-scale` multiplies every duration (`0.5` twice as fast, `2` twice as slow, `0` no motion at all, loops stopped, like reduced motion). Unset, nothing changes.
- Content added later (AJAX navigation, a SPA route, a builder preview): start it with `document.dispatchEvent(new CustomEvent('kodza:init', { detail: { root: container } }))`; before removing it, the same call with `'kodza:destroy'` stops it and puts the original markup back.

### Claude artifact (claude.ai)

- Paste the CSS in a `<style>` and the JS in a `<script>` at the end, in the artifact itself: it loads stylesheets only from Google Fonts and scripts only from a few CDNs, so no `<link>` or `<script src>` to Kodza.
- Writing the artifact file with a shell? Insert the downloaded files (Files) with a command instead of retyping them: a line `KODZA-CSS` alone inside the `<style>`, `KODZA-JS` inside the `<script>`, then `sed -e '/^KODZA-CSS$/{r kodza/kodza-annotation-arrow.css' -e 'd' -e '}' -e '/^KODZA-JS$/{r kodza/kodza-annotation-arrow.js' -e 'd' -e '}' page.html > artifact.html`.
- Font: load Geist from Google Fonts (allowed): `<link rel="stylesheet" href="https://fonts.googleapis.com/css2?family=Geist:wght@400;500;600;700&family=Geist+Mono:wght@400;500&display=swap">`. A site with its own type sets it once for every Kodza component, on `:root`, never by editing the CSS (unset, nothing changes): `--kz-font-label`, the face of the small labels (meta, captions, counters, hints, footer links, button labels); `--kz-font-label-size`, their size, one for all of them (`11px`…); `--kz-font-label-weight`, their weight; `--kz-font-label-tracking`, their letter-spacing; `--kz-font-label-case`, their case (`uppercase`…; code and units keep theirs); `--kz-font-label-leading`, their line-height (`1.45`…; buttons, pills and keys keep their box); `--kz-font-mono`, the monospace face (code, labels, counters).
- Motion: a site sets its pace once for every Kodza component, on `:root`, never by editing the CSS or the JS: `--kz-motion-scale` multiplies every duration (`0.5` twice as fast, `2` twice as slow, `0` no motion at all, loops stopped, like reduced motion). Unset, nothing changes.
- Dark mode: the viewer sets `data-theme="dark"` or `"light"` on `<html>`, or nothing when it follows the system. Write the Dark mode rules twice: inside `@media (prefers-color-scheme: dark)` with `:root:not([data-theme="light"])` in front of each selector, and with `:root[data-theme="dark"]` in front of each selector.

### WordPress

- HTML: a **Custom HTML** block (or a pattern / template part). WordPress keeps this markup as it is only for users allowed to post unfiltered HTML (Administrators; Super Admins on multisite): for anyone else it strips tags such as `<svg>`, `<input>` or `<dialog>`, so add it from the theme (a pattern or template part) instead.
- This one spans the page: a block theme keeps a Custom HTML block to the width of the text column, so put it inside a **Group** block set to **Full width**, with **Inner blocks use content width** turned off.
- CSS and JS: the downloaded files go in the theme, under `wp-content/themes/<your-theme>/kodza/` (the child theme if there is one), enqueued from its functions.php (or a code-snippets plugin):
  ```php
  add_action('wp_enqueue_scripts', function () {
    $dir = get_stylesheet_directory() . '/kodza/';
    $uri = get_stylesheet_directory_uri() . '/kodza/';
    wp_enqueue_style('kodza-annotation-arrow', $uri . 'kodza-annotation-arrow.css', [], filemtime($dir . 'kodza-annotation-arrow.css'));
    wp_enqueue_script('kodza-annotation-arrow', $uri . 'kodza-annotation-arrow.js', [], filemtime($dir . 'kodza-annotation-arrow.js'), true);
  });
  ```
  Scoped to `kodza-` classes, the CSS never touches the theme. One copy of the JS, whatever the number of blocks.
- No access to the theme files? The CSS can also go, as it is, in **Appearance → Customize → Additional CSS** (classic theme) or **Styles → Additional CSS** in the Site Editor (block theme).
- Theme with AJAX page transitions: fire `kodza:init` on the new content after each swap (and `kodza:destroy` on the old one).
- Performance plugin (WP Rocket, LiteSpeed Cache, Perfmatters…) with **Delay JavaScript execution** turned on: add `kodza` to the scripts it must not delay. Otherwise the component waits for the visitor's first scroll, tap or mouse move, and that first click can be lost.
- Colours: it takes the colour of the text around it (or keeps its own monochrome): nothing to point at the theme.
- WordPress turns straight quotes and `--` into typographic ones in the text of a Custom HTML block (not inside `<code>` or `<pre>`).

#### With Elementor

- HTML: an **HTML** widget (Elementor shows it to administrators only). It keeps the code exactly as pasted, straight quotes included.
- This one spans the page: give the widget its own container, **Content Width: Full Width**, padding 0.
- CSS and JS: as above. Elementor's Site Settings → Theme Style styles every button, field, link and image of the page, components included; the theme guard at the end of the CSS keeps the component's buttons, fields and link colours as they are.
- The Elementor editor redraws each widget after the page has loaded: without the script below, the component stays still in the editor preview (the published page works). Add it once per site, in the footer like the component's script (`kodza/elementor-editor.js`, or a code-snippets plugin):

```js
// Kodza in the Elementor editor: the editor redraws each HTML widget after the page has loaded.
// Start Kodza in what it draws, stop it in what it replaces or removes. Once per site.
window.addEventListener('elementor/frontend/init', () => {
  if (!elementorFrontend.isEditMode()) return;
  class KodzaWidget extends elementorModules.frontend.handlers.Base {
    onInit() {
      super.onInit();
      this.kodza = [...this.$element[0].children];
      document.dispatchEvent(new CustomEvent('kodza:init', { detail: { root: this.$element[0] } }));
    }
    onDestroy() {
      super.onDestroy();
      this.kodza.forEach((root) => document.dispatchEvent(new CustomEvent('kodza:destroy', { detail: { root } })));
    }
  }
  elementorFrontend.elementsHandler.attachHandler('html', KodzaWidget);
});
```

- No child theme: everything can go in the HTML widget instead, `<style>` with the CSS, the HTML, then `<script>` with the JS. It works on the page and in the editor without the script above.

### Shopify

- Files: `assets/kodza-annotation-arrow.css` and `assets/kodza-annotation-arrow.js` (the Files commands with `-o assets/…`).
- In the section: `{{ 'kodza-annotation-arrow.css' | asset_url | stylesheet_tag }}` and `<script src="{{ 'kodza-annotation-arrow.js' | asset_url }}" defer></script>`, then the HTML.
- The theme editor re-renders sections: restart them with
  `document.addEventListener('shopify:section:load', (e) => document.dispatchEvent(new CustomEvent('kodza:init', { detail: { root: e.target } })));`
  and the same with `shopify:section:unload` → `kodza:destroy`.

### React / Next.js

- Files, side by side (e.g. in `components/kodza/`): `AnnotationArrow.tsx` (below), the CSS block under Code saved as `annotation-arrow.css` and the JS block as `annotation-arrow.js`, both as they are. The HTML block is already inside the component: skip it.
- Use it: `import { AnnotationArrow } from '@/components/kodza/AnnotationArrow';` then `<AnnotationArrow>Start here. No sign-up.</AnnotationArrow>`. Props: `target` (`data-target`: ".hero-cta"), `vars` (the `--kz-…` variables listed under API, e.g. `vars={{ '--kz-annotation-arrow-ink': … }}`), `children` (the text, plain), `className`, `style` and the other props of its `<div>` (`onClick`, `aria-…`).
- Next.js App Router: it is a Client Component already (`'use client'`). Pages Router: Next.js takes global CSS only in `pages/_app`, so move the `import './annotation-arrow.css'` line there.
- Safe under StrictMode, client-side navigation and prop changes: when a prop changes, the `key` gives React a fresh element, `kodza:destroy` stops the script on the old one and `kodza:init` starts it on the new one.
- Built from your data (tabs, rows, options)? Add what the markup is made of to the `key`, as plain values (ids, text, numbers). What the visitor changes (the open tab, the sort, what they type) is the script's: follow it with `onClick` or `onInput` on the root, and change it from your code as a visitor would (click the tab; set the field's value, then dispatch a bubbling `input` event). Fields stay uncontrolled (`defaultValue`, `name`).

```tsx
'use client';
// Kodza — Annotation Arrow, for React. From https://kodza.dev/components/annotation-arrow/
// Kodza License: free to use, client work included. Not to resell or redistribute, ported or not: https://kodza.dev/docs/#print-license
// Next to this file: annotation-arrow.css and annotation-arrow.js, the component's CSS and JS from Kodza, as they are.
// Yours to edit: the markup is plain JSX below.
// The script changes this markup once React has rendered it (it adds layers, splits text, moves
// nodes), so React must not patch it afterwards. When a prop changes, the key gives React a fresh
// element: kodza:destroy stops the script on the old one, kodza:init starts it on the new one.
// data-kodza-manual keeps the script from starting it on its own: the effect below does, once
// React has hydrated the markup (on a page that streams in, the script can load first).
// Built from your data (tabs, rows, options)? Put what the markup is made of in the key, as plain
// values (ids, text, numbers): a change starts the script again on fresh markup. What the visitor
// changes (the open tab, the sort, what they type) is the script's: keep it out of the key, follow
// it with onClick or onInput on the root, and change it from your code as a visitor would (click
// the tab; set the field's value, then dispatch a bubbling input event).
import { useRef, useEffect, type ComponentPropsWithoutRef, type ComponentRef, type CSSProperties } from 'react';
import './annotation-arrow.css';

export type AnnotationArrowProps = Omit<ComponentPropsWithoutRef<'div'>, "children" | "vars" | "target"> & {
  /** data-target on the root (default: .hero-cta) */
  target?: ".hero-cta";
  /** Settings, as CSS variables on the root */
  vars?: {
    /** the note and its line — default: #0a0a0a */
    "--kz-annotation-arrow-ink"?: string | number;
    /** the line's thickness — default: 1.75px */
    "--kz-annotation-arrow-stroke"?: string | number;
    /** the note's widest, before it wraps — default: 240px */
    "--kz-annotation-arrow-width"?: string | number;
  };
  /** The text, plain: the script reads it and rebuilds the markup around it */
  children?: string;
  className?: string;
};

export function AnnotationArrow({ target = ".hero-cta", vars, children = "Start here. No sign-up.", className, style, ...rest }: AnnotationArrowProps) {
  const ref = useRef<ComponentRef<'div'>>(null);
  const classes = ["kodza-annotation-arrow", className].filter(Boolean).join(' ');
  // Everything the markup is made of: when it changes, React gets a fresh element (see the top)
  const key = JSON.stringify([classes, target, vars, children, style, rest]);

  // Starts the script on this element once React has rendered it, stops it when it goes
  useEffect(() => {
    const root = ref.current;
    let live = true;
    // @ts-ignore: a plain script, no types to find
    import('./annotation-arrow.js').then(() => {
      if (live) document.dispatchEvent(new CustomEvent('kodza:init', { detail: { root } }));
    });
    return () => {
      live = false;
      document.dispatchEvent(new CustomEvent('kodza:destroy', { detail: { root } }));
    };
  }, [key]);

  return (
    <div key={key} {...rest} className={classes} data-kodza-manual data-target={target} style={{ ...vars, ...style } as CSSProperties} ref={ref}>
      <p className="kodza-annotation-arrow__note">{children}</p>
    </div>
  );
}
```

## Code

```html
<div class="kodza-annotation-arrow" data-target=".hero-cta">
  <p class="kodza-annotation-arrow__note">Start here. No sign-up.</p>
</div>
```

```css
/* Kodza License: free to use, client work included. Not to resell or redistribute, ported or not: https://kodza.dev/docs/#print-license */
/* Kodza — Annotation Arrow
   A note that draws a hand-drawn arrow to the real thing it is about (data-target). The note is
   placed by your page, wherever you want it: the script works out the line from there. Without
   the script, the note is there, without its arrow. The colour, the line and the note are tuned
   with the --kz-annotation-arrow-* variables, the curve and the pen with the constants at the top
   of component.js, the target with data-target, the ring with data-mark="ring". */
.kodza-annotation-arrow {
  --kz-annotation-arrow-ink: #0a0a0a; /* the note and its line */
  --kz-annotation-arrow-stroke: 1.75px; /* the line's thickness */
  --kz-annotation-arrow-width: 240px; /* the note's widest, before it wraps */

  display: block;
  color: var(--kz-annotation-arrow-ink);
}

/* The width sits on the note, not the root: a theme that sizes its column's children leaves it alone */
.kodza-annotation-arrow__note {
  max-width: var(--kz-annotation-arrow-width);
  margin: 0;
  font-family: var(--kz-font-label, var(--kz-font-mono, ui-monospace, "SF Mono", Menlo, monospace));
  font-size: var(--kz-font-label-size, 13px);
  font-weight: var(--kz-font-label-weight, 400);
  line-height: var(--kz-font-label-leading, 1.45);
  letter-spacing: var(--kz-font-label-tracking, 0);
  text-transform: var(--kz-font-label-case, none);
  text-wrap: balance;
}

/* The drawing, laid by the script over the root at its corner: it runs out of it to the target */
.kodza-annotation-arrow__svg {
  position: absolute;
  z-index: 1;
  display: block;
  width: 1px;
  height: 1px;
  overflow: visible;
  pointer-events: none;
  fill: none;
  stroke: currentColor;
  stroke-width: var(--kz-annotation-arrow-stroke);
  stroke-linecap: round;
  stroke-linejoin: round;
}

/* The note is written from left to right before the line starts (only once the script is there) */
.kodza-annotation-arrow.is-ready .kodza-annotation-arrow__note {
  -webkit-mask-image: linear-gradient(90deg, #000 calc(var(--kz-annotation-arrow-written, 1) * (100% + 48px) - 48px), transparent calc(var(--kz-annotation-arrow-written, 1) * (100% + 48px)));
  mask-image: linear-gradient(90deg, #000 calc(var(--kz-annotation-arrow-written, 1) * (100% + 48px) - 48px), transparent calc(var(--kz-annotation-arrow-written, 1) * (100% + 48px)));
}

/* The line and its tip, drawn by the script */
.kodza-annotation-arrow__line,
.kodza-annotation-arrow__tip {
  fill: none;
  stroke: currentColor;
  stroke-width: var(--kz-annotation-arrow-stroke);
  stroke-linecap: round;
  stroke-linejoin: round;
}

/* kodza-guard 6f4dbd72fb6b — generated by Kodza, do not edit.
   Theme guard: keeps a site's own CSS (WordPress themes, Bootstrap, CSS resets…) off this
   component. :not(#_) is always true and weighs as much as an id, so these lines win over
   theme rules made of classes and tags. Customise the component through its --kz-* variables. */

/* What the browser gives, on everything the component leaves to it */

.kodza-annotation-arrow:not(#_),
.kodza-annotation-arrow__line:not(#_),
.kodza-annotation-arrow__tip:not(#_) {
  box-sizing: revert;
}

.kodza-annotation-arrow__svg:not(#_) {
  border: revert;
  margin: revert;
  padding: revert;
  border-radius: revert;
  outline: revert;
  text-decoration: revert;
  transition: revert;
  list-style: revert;
  box-sizing: revert;
  float: revert;
  background-color: revert;
  background-image: revert;
  box-shadow: revert;
  outline-offset: revert;
  appearance: revert;
  max-width: revert;
  max-height: revert;
  color: revert;
  font-family: revert;
  font-size: revert;
  font-weight: revert;
  font-style: revert;
  line-height: revert;
  letter-spacing: revert;
  text-transform: revert;
  text-underline-offset: revert;
  text-align: revert;
  text-indent: revert;
  text-shadow: revert;
  vertical-align: revert;
}

.kodza-annotation-arrow__note:not(#_) {
  border: revert;
  padding: revert;
  border-radius: revert;
  outline: revert;
  text-decoration: revert;
  transition: revert;
  list-style: revert;
  box-sizing: revert;
  float: revert;
  position: revert;
  background-color: revert;
  background-image: revert;
  box-shadow: revert;
  outline-offset: revert;
  appearance: revert;
  max-height: revert;
  color: revert;
  font-style: revert;
  text-underline-offset: revert;
  text-align: revert;
  text-indent: revert;
  text-shadow: revert;
  vertical-align: revert;
}

.kodza-annotation-arrow__note:not(#_):where(:not([hidden])) {
  display: revert;
}

.kodza-annotation-arrow__note:not(#_):where([hidden]) {
  display: none;
}

/* The component's own rules, one step stronger: real buttons and fields, what it sets on tags themes style (links, lists, headings, images…), and the root width (a theme may narrow it, never widen it) */

.kodza-annotation-arrow__note:not(#_) {
  max-width: var(--kz-annotation-arrow-width);
  margin: 0;
  font-family: var(--kz-font-label, var(--kz-font-mono, ui-monospace, "SF Mono", Menlo, monospace));
  font-size: var(--kz-font-label-size, 13px);
  font-weight: var(--kz-font-label-weight, 400);
  line-height: var(--kz-font-label-leading, 1.45);
  letter-spacing: var(--kz-font-label-tracking, 0);
  text-transform: var(--kz-font-label-case, none);
}

.kodza-annotation-arrow__svg:not(#_) {
  position: absolute;
  display: block;
}
```

```js
// Kodza License: free to use, client work included. Not to resell or redistribute, ported or not: https://kodza.dev/docs/#print-license
// Kodza — Annotation Arrow
// A note that draws a hand-drawn arrow to the real thing it is about: data-target is a CSS
// selector, and the closest match around the note is the target. The script works out the curve
// between the two boxes, bows it out on the side where it crosses neither, and draws it when the
// note enters the screen: the note is written, then the line, then its tip. It redraws itself
// when the layout moves (a new width, a font that loads, the note put under its target on a
// phone). data-mark="ring" circles the target instead, in the same stroke as the line.
// `kodza:replay` on the root draws it again. The figures you can tune are the constants below;
// the colour, the line and the note are in the CSS.
(() => {
  const SELECTOR = '.kodza-annotation-arrow';
  const SPEED = 460; // px of line a second
  const WRITE = 340; // px of note a second, written from left to right
  const RAMP = 160; // ms the pen takes to reach its speed, and to stop
  const LIFT = 150; // ms between the note, the line and its tip
  const GAP = 10; // px of air between the line and the boxes it joins
  const BEND = 0.3; // how far the line bows out, as a share of its length…
  const BOW = [16, 110]; // …kept between these, in px
  const TIP = [12, 9.5]; // px, the two strokes of the tip…
  const TIP_ANGLE = 28; // …and their angle to the line, in degrees
  const RING = [10, 10]; // px the ring stands off the target, at its sides and above and below…
  const CLEAR = 2; // …and the least it keeps off the target's corners, leaning and closing in
  const ROOM = 16; // px the line may run past the note and the target before it counts as a detour
  const TURN = 1.1; // turns of the ring: a hand closes it a little past where it started
  const TILT = -4; // degrees the ring leans
  const reduceMotion = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  // The site's pace, --kz-motion-scale (set on :root, read on the instance): every duration of the
  // script times it, and 0 moves nothing, like reduced motion
  const paceOf = (el) => {
    const pace = parseFloat(getComputedStyle(el).getPropertyValue('--kz-motion-scale'));
    return pace >= 0 ? pace : 1;
  };
  // How far a hand is along a stroke `time` ms long, `t` ms in (0 to 1): it picks up speed over
  // `ramp` ms, runs at a steady speed, and slows down over the last `ramp` ms
  const hand = (t, time, ramp) => {
    const r = Math.min(ramp, time / 2);
    const run = time - r; // the length, in ms at full speed
    if (t <= 0) return 0;
    if (t >= time) return 1;
    if (t < r) return (t * t) / (2 * r) / run;
    if (t <= time - r) return (t - r / 2) / run;
    return 1 - (time - t) ** 2 / (2 * r) / run;
  };

  // A little plane geometry: points, the middle of a box, a box's edge and the ring around one
  const pt = (x, y) => ({ x, y });
  const along = (a, b, k) => pt(a.x + (b.x - a.x) * k, a.y + (b.y - a.y) * k);
  const middle = (box) => pt(box.x + box.w / 2, box.y + box.h / 2);
  const turn = (x, y, a) => pt(x * Math.cos(a) - y * Math.sin(a), x * Math.sin(a) + y * Math.cos(a));
  const fixed = (p) => `${p.x.toFixed(1)} ${p.y.toFixed(1)}`;
  // Where the ray from the middle of `box` towards `to` comes out of it, `gap` px past its edge
  const edge = (box, to, gap) => {
    const c = middle(box);
    const dx = to.x - c.x || 1e-6;
    const dy = to.y - c.y || 1e-6;
    const k = Math.min((box.w / 2 + gap) / Math.abs(dx), (box.h / 2 + gap) / Math.abs(dy));
    return pt(c.x + dx * k, c.y + dy * k);
  };
  // The ring around `box`: an oval a little wider than it, leaning by TILT, that a hand opens a
  // little wide and closes a little tight. `touch(p, shift)` is where a line from p runs into it
  // (the point facing p, `shift` radians round), which way it then goes round and the way it is
  // heading there (`t`), `loop` the ring drawn from there, `inside(p, size)` whether p falls in
  // it (grown by `size`),
  // `box` the box it fills
  const ringOf = (box) => {
    const c = middle(box);
    const lean = (TILT * Math.PI) / 180;
    const OPEN = 1.06; // the ring's first point, as a share of its size…
    const SHUT = 0.96; // …and its last
    // Grown as a whole until the target's corners, turned with its lean, stay CLEAR px inside it
    // where the hand closes it tightest: a long word would cut through its ends otherwise
    const base = [box.w / 2 + RING[0], (box.h / 2) * 1.3 + RING[1]];
    const corners = [1, -1].map((side) => turn(box.w / 2 + CLEAR, side * (box.h / 2 + CLEAR), -lean));
    const grow = Math.max(1, ...corners.map((q) => Math.hypot(q.x / base[0], q.y / base[1]) / SHUT));
    const rx = base[0] * grow;
    const ry = base[1] * grow;
    const at = (angle, grow = 1) => {
      const p = turn(Math.cos(angle) * rx * grow, Math.sin(angle) * ry * grow, lean);
      return pt(c.x + p.x, c.y + p.y);
    };
    // p in the ring's own frame, where it is a circle of radius 1
    const unit = (p) => {
      const q = turn(p.x - c.x, p.y - c.y, -lean);
      return pt(q.x / rx, q.y / ry);
    };
    const touch = (p, shift) => {
      const u = unit(p);
      const angle = Math.atan2(u.y, u.x) + shift;
      // Round the way the line from p is heading when it gets there
      const v = pt(Math.cos(angle) * OPEN - u.x, Math.sin(angle) * OPEN - u.y);
      const dir = Math.sign(v.y * Math.cos(angle) - v.x * Math.sin(angle)) || 1;
      const t = turn(-Math.sin(angle) * rx * dir, Math.cos(angle) * ry * dir, lean);
      const size = Math.hypot(t.x, t.y) || 1;
      return { p: at(angle, OPEN), angle, dir, t: pt(t.x / size, t.y / size) };
    };
    const loop = (angle, dir) => {
      const steps = Math.ceil(48 * TURN);
      return Array.from({ length: steps + 1 }, (_, i) => at(angle + (dir * 2 * Math.PI * TURN * i) / steps, OPEN + ((SHUT - OPEN) * i) / steps));
    };
    const inside = (p, size = 1) => {
      const u = unit(p);
      return u.x ** 2 + u.y ** 2 < size ** 2;
    };
    return { touch, loop, inside, box: { x: c.x - rx, y: c.y - ry, w: 2 * rx, h: 2 * ry } };
  };
  // A smooth path through points (Catmull-Rom, written as cubic curves)
  const through = (points) => {
    let d = '';
    for (let i = 0; i < points.length - 1; i += 1) {
      const [a, b, c, e] = [points[i - 1] || points[i], points[i], points[i + 1], points[i + 2] || points[i + 1]];
      d += ` C ${fixed(pt(b.x + (c.x - a.x) / 6, b.y + (c.y - a.y) / 6))} ${fixed(pt(c.x - (e.x - b.x) / 6, c.y - (e.y - b.y) / 6))} ${fixed(c)}`;
    }
    return d;
  };

  // One instance. Everything it starts is tied to `signal`, so kodza:destroy stops it all
  function mount(root, signal) {
    const note = root.querySelector('.kodza-annotation-arrow__note');
    const selector = root.dataset.target;
    const match = (el) => {
      try {
        return el.querySelector(selector);
      } catch {
        return null; // a selector that does not parse points at nothing
      }
    };
    // The closest match around the note: one note per button, as many as the page has
    let scope = root.parentElement;
    while (selector && scope && !match(scope)) scope = scope.parentElement;
    const target = scope && match(scope);
    if (!note || !target) return;
    const pace = paceOf(root);
    // The still path: drawn at once (and still redrawn when the layout moves). The pace slows the pen
    const still = reduceMotion || !pace;
    const ringed = root.dataset.mark === 'ring';

    // The drawing, in an svg laid at the root's corner and counted in the root's own pixels: the
    // line (and the ring, in the same stroke) and the tip
    const svg = document.createElementNS(NS, 'svg');
    svg.setAttribute('class', 'kodza-annotation-arrow__svg');
    svg.setAttribute('aria-hidden', 'true');
    const draw = (name) => {
      const el = svg.appendChild(document.createElementNS(NS, 'path'));
      el.setAttribute('class', `kodza-annotation-arrow__${name}`);
      return el;
    };
    const line = draw('line');
    const tip = ringed ? null : draw('tip');
    root.prepend(svg);

    // The curve from `from` to `to`, bowed out on `side` (1 or -1): it leaves at a slant and
    // comes in almost straight, like a hand that aims at the end
    const bowed = (from, to, side) => {
      const dx = to.x - from.x;
      const dy = to.y - from.y;
      const length = Math.hypot(dx, dy) || 1;
      const bow = Math.min(Math.max(length * BEND, BOW[0]), BOW[1]) * side;
      const a = along(from, to, 0.28);
      const b = along(from, to, 0.72);
      return [pt(a.x - (dy / length) * bow, a.y + (dx / length) * bow), pt(b.x - (dy / length) * bow * 0.4, b.y + (dx / length) * bow * 0.4)];
    };
    const bezier = (p, k) => {
      const s = 1 - k;
      const w = [s * s * s, 3 * s * s * k, 3 * s * k * k, k * k * k];
      return pt(p.reduce((sum, q, i) => sum + q.x * w[i], 0), p.reduce((sum, q, i) => sum + q.y * w[i], 0));
    };
    const within = (box, p) => p.x > box.x - 2 && p.x < box.x + box.w + 2 && p.y > box.y - 2 && p.y < box.y + box.h + 2;

    // The geometry, from where the note and the target are now. Each way the line can go (bowed
    // to one side or the other, and for the ring, joining it at the point that faces the note or
    // a little round either way) is tried: the
    // one that crosses neither box wins, then the one that takes no detour around them, then
    // (for an arrow) the one that bows upwards like a thrown line, then the shorter one
    const solve = () => {
      const at = boxesIn(root);
      const corner = at(svg);
      const local = (el) => {
        const box = at(el);
        return { x: box.x - corner.x, y: box.y - corner.y, w: box.w, h: box.h };
      };
      const from = local(note);
      const to = local(target);
      const ring = ringed && ringOf(to);
      const apart = from.x > to.x + to.w + GAP || to.x > from.x + from.w + GAP || from.y > to.y + to.h + GAP || to.y > from.y + from.h + GAP;
      line.setAttribute('d', '');
      tip?.setAttribute('d', '');
      if (!apart) return from; // a note on its target: nothing to point at

      const reach = ring ? ring.box : to;
      const left = Math.min(from.x, reach.x) - ROOM;
      const right = Math.max(from.x + from.w, reach.x + reach.w) + ROOM;
      const top = Math.min(from.y, reach.y) - ROOM;
      const bottom = Math.max(from.y + from.h, reach.y + reach.h) + ROOM;
      const ways = [];
      (ring ? [1] : [1, -1]).forEach((side) => (ring ? [-0.6, -0.3, 0, 0.3, 0.6] : [0]).forEach((shift) => {
        // The line comes into the target GAP px out of it, aimed at its middle, or swings into the
        // ring along it in a single bend, so the two read as one stroke
        const land = (toward) => (ring ? ring.touch(toward, shift) : { p: edge(to, toward, GAP) });
        const aim = (start, end) => {
          if (!ring) return bowed(start, end.p, side);
          const reach = Math.min(Math.max(Math.hypot(end.p.x - start.x, end.p.y - start.y) * 0.25, 20), 56);
          const join = pt(end.p.x - end.t.x * reach, end.p.y - end.t.y * reach);
          return [along(start, join, 0.45), join];
        };
        let start = edge(from, middle(to), GAP);
        let end = land(middle(from));
        let bend = aim(start, end);
        for (let i = 0; i < 3; i += 1) {
          start = edge(from, bend[0], GAP);
          end = land(ring ? start : bend[1]);
          bend = aim(start, end);
        }
        const curve = [start, bend[0], bend[1], end.p];
        let cost = 0;
        for (let k = 1; k < 40; k += 1) {
          const p = bezier(curve, k / 40);
          // Into the ring, the line keeps clear of it until its last stretch, where it joins it
          if (within(from, p) || (ring ? ring.inside(p, k < 34 ? 1.25 : 1) : within(to, p))) cost += 1;
          else if (p.x < left || p.x > right || p.y < top || p.y > bottom) cost += 0.25;
        }
        // An arrow bows upwards, like a thrown line. Then the shorter way
        const bulge = bezier(curve, 0.5);
        if (!ring && bulge.y > (start.y + end.p.y) / 2 + 1) cost += 0.5;
        cost += Math.hypot(end.p.x - start.x, end.p.y - start.y) / 4000;
        ways.push({ curve, end, cost });
      }));
      const way = ways.reduce((best, next) => (next.cost < best.cost ? next : best));
      const [start, b1, b2, end] = way.curve;
      let d = `M ${fixed(start)} C ${fixed(b1)} ${fixed(b2)} ${fixed(end)}`;
      if (ring) d += through(ring.loop(way.end.angle, way.end.dir));
      line.setAttribute('d', d);
      if (tip) {
        // Two short strokes back from the end, either side of the way the line came in
        const length = Math.hypot(end.x - b2.x, end.y - b2.y) || 1;
        const back = (deg, size) => {
          const p = turn(((b2.x - end.x) / length) * size, ((b2.y - end.y) / length) * size, (deg * Math.PI) / 180);
          return pt(end.x + p.x, end.y + p.y);
        };
        tip.setAttribute('d', `M ${fixed(back(TIP_ANGLE, TIP[0]))} L ${fixed(end)} L ${fixed(back(-TIP_ANGLE, TIP[1]))}`);
      }
      return from;
    };

    // The timeline, in ms: the note written at WRITE, then each stroke at SPEED, a lift between
    let parts = [];
    let write = 0;
    let total = 0;
    const time = (from) => {
      write = Math.max((from.w / WRITE) * 1000 * pace, 1);
      let clock = write;
      parts = [line, tip].filter(Boolean).map((el) => {
        const units = el.getAttribute('d') ? el.getTotalLength() : 0;
        const start = clock + LIFT * pace;
        const span = Math.max((units / SPEED) * 1000 * pace, 1) + RAMP * pace;
        clock = start + span;
        return { el, units, start, span };
      });
      total = clock;
    };

    // The drawing at `t` ms of its timeline: the note written up to the pen, the strokes before it
    // down, the one under it inked by its length, the next ones not started
    let shown = 0;
    const render = (t) => {
      shown = t;
      root.style.setProperty('--kz-annotation-arrow-written', hand(t, write, RAMP * pace).toFixed(3));
      parts.forEach((part) => {
        const u = hand(t - part.start, part.span, RAMP * pace);
        if (u < 1) inkTo(part.el, u * part.units, part.units);
        else part.el.style.strokeDasharray = part.el.style.visibility = '';
      });
    };

    let frame = 0;
    let queued = 0;
    signal.addEventListener('abort', () => {
      cancelAnimationFrame(frame);
      cancelAnimationFrame(queued);
    });

    // On entering the screen: the pen starts once, from the note. At the foot of a page the note
    // may never get that far up: once the page goes no further down, a note in full view starts
    let seen = null;
    const wait = new AbortController();
    signal.addEventListener('abort', () => wait.abort());
    const play = () => {
      seen?.disconnect();
      wait.abort();
      cancelAnimationFrame(frame);
      if (still) return render(total);
      const begin = performance.now();
      const tick = (now) => {
        render(Math.min(now - begin, total));
        frame = shown < total ? requestAnimationFrame(tick) : 0;
      };
      render(0);
      frame = requestAnimationFrame(tick);
    };

    // The layout moved (a width, a font, the note sent under its target): the curve is worked out
    // again and drawn as far as the pen had gone, all of it once done
    const redo = () => {
      cancelAnimationFrame(queued);
      queued = requestAnimationFrame(() => {
        const done = shown >= total;
        time(solve());
        render(done ? total : shown);
      });
    };

    time(solve());
    render(still ? total : 0);
    if (!still) {
      seen = new IntersectionObserver((entries) => entries.some((entry) => entry.isIntersecting) && play(), {
        rootMargin: '0px 0px -15% 0px',
        threshold: 0.6,
      });
      seen.observe(root);
      signal.addEventListener('abort', () => seen.disconnect());
      const foot = () => {
        const box = root.getBoundingClientRect();
        const end = document.documentElement.scrollHeight - innerHeight - scrollY <= 1;
        if (end && box.height && box.top >= 0 && box.bottom <= innerHeight) play();
      };
      window.addEventListener('scroll', foot, { passive: true, signal: wait.signal });
      foot(); // a page too short to scroll never sends a scroll event
    }
    root.addEventListener('kodza:replay', play, { signal });
    const moved = new ResizeObserver(redo);
    [root, target, scope].forEach((el) => moved.observe(el));
    signal.addEventListener('abort', () => moved.disconnect());
    window.addEventListener('resize', redo, { passive: true, signal });
    document.fonts?.ready.then(() => signal.aborted || redo());
  }

  // ---------- Pen engine: the same block in Scroll Path, Path Draw and Annotation Arrow ----------
  // Boxes measured in a root's own pixels, a line inked by its length (stroke-dasharray: the `d`
  // of a path is never animated, Safari would not play it) and a pen that moves along it at a
  // steady speed. Nothing in it knows the component around it
  const NS = 'http://www.w3.org/2000/svg';
  const inOut = (t) => (t < 0.5 ? 4 * t * t * t : 1 - (-2 * t + 2) ** 3 / 2);
  // Where an element sits in `root`, in the root's own pixels: a parent scaled by transform (a
  // thumbnail, a theme) does not shift the drawing
  const boxesIn = (root) => {
    const box = root.getBoundingClientRect();
    const scale = box.width / root.offsetWidth || 1;
    return (el) => {
      const r = el.getBoundingClientRect();
      return { x: (r.left - box.left) / scale, y: (r.top - box.top) / scale, w: r.width / scale, h: r.height / scale };
    };
  };
  // Inks a shape up to `length` px along its outline (`total` px long)
  const inkTo = (el, length, total) => {
    el.style.strokeDasharray = `${length.toFixed(1)} ${Math.ceil(total + 2)}`;
    el.style.visibility = length > 0.5 ? '' : 'hidden';
  };
  // One frame of the pen (`dt` ms): from `shown` towards `target`, at most `speed` px a second,
  // a little faster when it lifts the ink off. `glide` eases it in (1: a steady speed)
  const penStep = (shown, target, dt, speed, glide = 1) => {
    const cap = ((speed * dt) / 1000) * (target < shown ? 1.5 : 1);
    const next = shown + Math.sign(target - shown) * Math.min(Math.abs(target - shown) * glide, cap);
    return Math.abs(target - next) < 0.5 ? target : next;
  };
  // ---------- End of the pen engine ----------
  // Kodza lifecycle, the same in every component: `kodza:init` starts the instances inside
  // event.detail.root (the whole page by default), `kodza:destroy` stops them and puts their
  // markup back. For themes and apps that swap content without a page load. Each running root
  // keeps its markup as written under KODZA, shared by every Kodza script on the page: a Kodza
  // component inside another one is saved as written, not half-started, and stopped with it. Two
  // components on one root (a reveal on a stat card) both start, and stop together.
  const KODZA = Symbol.for('kodza');
  const RUNNING = Symbol.for(`kodza ${SELECTOR}`); // a root this component runs on, for every copy of this script
  const instances = new WeakMap();
  const find = (scope = document) => [scope, ...scope.querySelectorAll(SELECTOR)].filter((el) => el.matches?.(SELECTOR));
  const attrsOf = (el) => [...el.attributes].map((a) => [a.name, a.value]);
  const put = (el, saved) => {
    [...el.attributes].forEach((a) => el.removeAttribute(a.name));
    saved.attrs.forEach(([name, value]) => el.setAttribute(name, value));
    el.innerHTML = saved.html;
  };
  // The markup inside a root as written: Kodza components already running in it give back their own
  const written = (root) => {
    const all = [...root.querySelectorAll('*')];
    if (!all.some((el) => el[KODZA])) return root.innerHTML;
    const copy = root.cloneNode(true);
    const twins = copy.querySelectorAll('*');
    let last = null;
    all.forEach((el, i) => {
      if (!el[KODZA] || last?.contains(el)) return;
      last = el;
      put(twins[i], el[KODZA]);
    });
    return copy.innerHTML;
  };
  const init = (scope) => find(scope).forEach((root) => {
    // Already running, maybe from another copy of this script. Marked is-ready with no Kodza component
    // running on it, a root is a copy of a started one (a cloned slide): it is left as it is
    if (root[RUNNING] || (root.classList.contains('is-ready') && !root[KODZA])) return;
    // Rendered by React (data-kodza-manual): React starts it, with an init aimed at that markup once
    // it has hydrated it. Any earlier start would change markup React has not taken over yet
    const owner = root.closest('[data-kodza-manual]');
    if (owner && !(scope && owner.contains(scope))) return;
    const controller = new AbortController();
    // Another Kodza component already running on this root: its markup as written is kept, and the
    // two stop together
    const before = root[KODZA];
    const saved = { html: before ? before.html : written(root), attrs: before ? before.attrs : attrsOf(root), stop: () => destroy(root) };
    if (before) before.above = saved;
    instances.set(root, { controller, saved, before });
    root[KODZA] = saved;
    root[RUNNING] = true;
    mount(root, controller.signal);
    root.classList.add('is-ready');
  });
  const destroy = (scope) => find(scope).forEach((root) => {
    const instance = instances.get(root);
    if (!instance) return;
    instances.delete(root);
    instance.saved.above?.stop(); // a Kodza component started after it on the same root stops first
    // The Kodza components running inside it stop first: once its markup is put back, their own
    // script could not find them any more
    root.querySelectorAll('*').forEach((el) => el[KODZA]?.stop());
    instance.controller.abort();
    delete root[RUNNING];
    // Started on top of another one: that one stops next, and puts the markup back
    if (instance.before) {
      delete instance.before.above;
      root[KODZA] = instance.before;
      return instance.before.stop();
    }
    delete root[KODZA];
    put(root, instance.saved);
  });
  document.addEventListener('kodza:init', (event) => init(event.detail?.root));
  document.addEventListener('kodza:destroy', (event) => destroy(event.detail?.root));
  init();
  // Loaded in <head>, the script runs before the markup exists: once more when it is parsed
  if (document.readyState === 'loading') document.addEventListener('DOMContentLoaded', () => init(), { once: true });
})();
```

Free to use, from Kodza (https://kodza.dev).