# Table of Contents

> A summary card built from your headings: an ink marker follows the section you read, a ring fills, the time left counts down. A bar on phones.

Navigation · toc, scroll, nav, article · HTML, CSS, vanilla JS · no dependencies · updated 2026-10-16
Demo: https://kodza.dev/components/table-of-contents/

Takes the whole screen (or reacts to the page scroll): give it a page, not a small box.

## Files

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

- [`kodza-table-of-contents.css`](https://kodza.dev/registry/table-of-contents/kodza-table-of-contents.css) · 15.3 KB
- [`kodza-table-of-contents.js`](https://kodza.dev/registry/table-of-contents/kodza-table-of-contents.js) · 7.6 KB
- [`kodza-table-of-contents.html`](https://kodza.dev/registry/table-of-contents/kodza-table-of-contents.html) · 1.0 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-table-of-contents.css https://kodza.dev/registry/table-of-contents/kodza-table-of-contents.css
curl -fsSL --create-dirs -o kodza/kodza-table-of-contents.js https://kodza.dev/registry/table-of-contents/kodza-table-of-contents.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-toc`
- Variables (set them on the root element itself: it declares its own defaults):
  - `--kz-toc-bg: #ffffff`
  - `--kz-toc-fg: #0a0a0a`
  - `--kz-toc-muted: rgba(10, 10, 10, 0.6)`
  - `--kz-toc-faint: rgba(10, 10, 10, 0.4)`
  - `--kz-toc-line: rgba(10, 10, 10, 0.08)`
  - `--kz-toc-ink: #0a0a0a`
  - `--kz-toc-top: 32px`
  - `--kz-toc-offset: 32px`
  - `--kz-toc-duration: 0.5s`
  - `--kz-toc-ease: cubic-bezier(0.22, 1, 0.36, 1)`
  - `--kz-toc-mono: ui-monospace, "SF Mono", Menlo, monospace`
- Attributes:
  - `data-headings`
  - `data-target`
- 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-toc {
    --kz-toc-bg: #161616;
    --kz-toc-fg: #f2f2f0;
    --kz-toc-muted: rgba(242, 242, 240, 0.6);
    --kz-toc-faint: rgba(242, 242, 240, 0.62);
    --kz-toc-line: rgba(255, 255, 255, 0.1);
    --kz-toc-ink: #f2f2f0;
  }
}
```

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

## Use it

### Plain HTML page

- CSS: `kodza/kodza-table-of-contents.css` next to the page (the Files commands as they are), linked in `<head>`: `<link rel="stylesheet" href="kodza/kodza-table-of-contents.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-table-of-contents.js`, loaded with `<script src="kodza/kodza-table-of-contents.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. 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">`.
- 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$/{r kodza/kodza-table-of-contents.css' -e 'd' -e '}' -e '/^KODZA-JS$/{r kodza/kodza-table-of-contents.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">`.
- 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 **Wide width**, with **Inner blocks use content width** turned off. In Hello Elementor (without Elementor), skip the Group: its Wide width reaches 80 px past the text column on every screen, off the page on a phone, and its column is already wide.
- 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-table-of-contents', $uri . 'kodza-table-of-contents.css', [], filemtime($dir . 'kodza-table-of-contents.css'));
    wp_enqueue_script('kodza-table-of-contents', $uri . 'kodza-table-of-contents.js', [], filemtime($dir . 'kodza-table-of-contents.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: by default, match the theme's palette. After the component's CSS, point these variables at the theme's colours, on the component root, Kodza's value as the fallback:
  `.kodza-toc { --kz-toc-fg: var(TEXT, #0a0a0a); --kz-toc-bg: var(BACKGROUND, #ffffff); --kz-toc-ink: var(ACCENT, #0a0a0a); }`
  TEXT, BACKGROUND and ACCENT (the colour the theme fills its own buttons with) are the theme's own colour variables — block themes (theme.json, like Twenty Twenty-Five): `--wp--preset--color--contrast`, `--wp--preset--color--base`, `--wp--preset--color--contrast` (they fill their buttons with it; their accent-1… colours are decorative); Astra: `--ast-global-color-2`, `--ast-global-color-4`, `--ast-global-color-0`; Kadence: `--global-palette3`, `--global-palette9`, `--global-palette1`; GeneratePress: `--contrast`, `--base-3`, `--accent`; Blocksy: `--theme-palette-color-4`, `--theme-palette-color-8`, `--theme-palette-color-1`. Use only these names, and only if the site really has them (the theme's CSS, or Styles → Colors): the `--wp--preset--color--black`, `--white`, `--vivid-…` that WordPress adds everywhere are not the theme's palette. Another theme, or one without these variables (Hello Elementor, OceanWP): leave the variables alone, it keeps Kodza's monochrome; same when the developer asks for monochrome or the Kodza look. Leave the translucent greys (`rgba(10, 10, 10, …)`) as they are: they suit any light background. On a dark palette, set the other variables from Dark mode too.
- 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.
- 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. This one reads the page around it, and a script in the widget runs before the rest of the page exists: put its `<script>` in an HTML widget at the bottom of the page instead.

### Shopify

- Files: `assets/kodza-table-of-contents.css` and `assets/kodza-table-of-contents.js` (the Files commands with `-o assets/…`).
- In the section: `{{ 'kodza-table-of-contents.css' | asset_url | stylesheet_tag }}` and `<script src="{{ 'kodza-table-of-contents.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/`): `TableOfContents.tsx` (below), the CSS block under Code saved as `table-of-contents.css` and the JS block as `table-of-contents.js`, both as they are. The HTML block is already inside the component: skip it.
- Use it: `import { TableOfContents } from '@/components/kodza/TableOfContents';` then `<TableOfContents />`. Props: `vars` (the `--kz-…` variables listed under API, e.g. `vars={{ '--kz-toc-bg': … }}`), `className`, `style` and the other props of its `<nav>` (`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 './table-of-contents.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.

```tsx
'use client';
// Kodza — Table of Contents, for React. From https://kodza.dev/components/table-of-contents/
// 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: table-of-contents.css and table-of-contents.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.
import { useRef, useEffect, type ComponentPropsWithoutRef, type ComponentRef, type CSSProperties } from 'react';
import './table-of-contents.css';

export type TableOfContentsProps = Omit<ComponentPropsWithoutRef<'nav'>, "children" | "vars"> & {
  /** Settings, as CSS variables on the root */
  vars?: {
    /** default: #ffffff */
    "--kz-toc-bg"?: string | number;
    /** default: #0a0a0a */
    "--kz-toc-fg"?: string | number;
    /** default: rgba(10, 10, 10, 0.6) */
    "--kz-toc-muted"?: string | number;
    /** default: rgba(10, 10, 10, 0.4) */
    "--kz-toc-faint"?: string | number;
    /** default: rgba(10, 10, 10, 0.08) */
    "--kz-toc-line"?: string | number;
    /** default: #0a0a0a */
    "--kz-toc-ink"?: string | number;
    /** default: 32px */
    "--kz-toc-top"?: string | number;
    /** default: 32px */
    "--kz-toc-offset"?: string | number;
    /** default: 0.5s */
    "--kz-toc-duration"?: string | number;
    /** default: cubic-bezier(0.22, 1, 0.36, 1) */
    "--kz-toc-ease"?: string | number;
    /** default: ui-monospace, "SF Mono", Menlo, monospace */
    "--kz-toc-mono"?: string | number;
  };
  className?: string;
};

export function TableOfContents({ vars, className, style, ...rest }: TableOfContentsProps) {
  const ref = useRef<ComponentRef<'nav'>>(null);
  const classes = ["kodza-toc", 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, vars, 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('./table-of-contents.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 (
    <nav aria-label="On this page" key={key} {...rest} className={classes} style={{ ...vars, ...style } as CSSProperties} ref={ref}>
      <button className="kodza-toc__head" type="button" aria-expanded="true">
        <span className="kodza-toc__ring" aria-hidden="true">
          <svg viewBox="0 0 20 20">
            <circle className="kodza-toc__ring-track" cx="10" cy="10" r="8" />
            <circle className="kodza-toc__ring-fill" cx="10" cy="10" r="8" pathLength="1" />
          </svg>
        </span>
        {' '}
        <span className="kodza-toc__label">
          <span className="kodza-toc__title">On this page</span>
          {' '}
          <span className="kodza-toc__current" />
        </span>
        {' '}
        <span className="kodza-toc__percent">0%</span>
        {' '}
        <svg className="kodza-toc__chevron" viewBox="0 0 16 16" aria-hidden="true">
          <path d="M4 6.5 8 10.5l4-4" />
        </svg>
      </button>
      <div className="kodza-toc__body">
        <div className="kodza-toc__inner">
          <ol className="kodza-toc__list" />
          <div className="kodza-toc__foot">
            <span className="kodza-toc__left" />
            {' '}
            <button className="kodza-toc__top" type="button">Back to top</button>
          </div>
        </div>
      </div>
    </nav>
  );
}
```

## Code

```html
<nav class="kodza-toc" aria-label="On this page">
  <button class="kodza-toc__head" type="button" aria-expanded="true">
    <span class="kodza-toc__ring" aria-hidden="true">
      <svg viewBox="0 0 20 20"><circle class="kodza-toc__ring-track" cx="10" cy="10" r="8"/><circle class="kodza-toc__ring-fill" cx="10" cy="10" r="8" pathLength="1"/></svg>
    </span>
    <span class="kodza-toc__label">
      <span class="kodza-toc__title">On this page</span>
      <span class="kodza-toc__current"></span>
    </span>
    <span class="kodza-toc__percent">0%</span>
    <svg class="kodza-toc__chevron" viewBox="0 0 16 16" aria-hidden="true"><path d="M4 6.5 8 10.5l4-4"/></svg>
  </button>
  <div class="kodza-toc__body">
    <div class="kodza-toc__inner">
      <ol class="kodza-toc__list"></ol>
      <div class="kodza-toc__foot">
        <span class="kodza-toc__left"></span>
        <button class="kodza-toc__top" type="button">Back to top</button>
      </div>
    </div>
  </div>
</nav>
```

```css
/* Kodza License: free to use, client work included. Not to resell or redistribute, ported or not: https://kodza.dev/docs/#print-license */
/* Kodza — Table of Contents
   A summary card for a long article, built from its headings (h2 numbered, h3 nested): an ink
   marker slides to the section you are reading, a ring fills with your progress, the time
   left counts down, and "Back to top" shows up once you are in. Sticky beside the article;
   on small screens it folds into a bar that names the current section and opens on tap.
   In WordPress, set data-target=".entry-content".
   Everything is tuned with the --kz-toc-* variables. */
.kodza-toc {
  --kz-toc-bg: #ffffff;
  --kz-toc-fg: #0a0a0a;
  --kz-toc-muted: rgba(10, 10, 10, 0.6);
  --kz-toc-faint: rgba(10, 10, 10, 0.4);
  --kz-toc-line: rgba(10, 10, 10, 0.08);
  --kz-toc-ink: #0a0a0a;
  --kz-toc-top: 32px;
  --kz-toc-offset: 32px;
  --kz-toc-duration: 0.5s;
  --kz-toc-ease: cubic-bezier(0.22, 1, 0.36, 1);
  --kz-toc-mono: ui-monospace, "SF Mono", Menlo, monospace;

  position: sticky;
  top: var(--kz-toc-top);
  border-radius: 16px;
  background: var(--kz-toc-bg);
  box-shadow: inset 0 0 0 1px var(--kz-toc-line);
  color: var(--kz-toc-fg);
}

/* The head: progress ring, title (or the current section, folded), percentage */
.kodza-toc__head {
  display: flex;
  align-items: center;
  gap: 10px;
  width: 100%;
  padding: 16px 18px;
  border: 0;
  border-radius: 16px;
  background: none;
  color: inherit;
  font: inherit;
  text-align: left;
  cursor: pointer;
}

.kodza-toc__head:focus-visible,
.kodza-toc__link:focus-visible,
.kodza-toc__top:focus-visible {
  outline: 2px solid var(--kz-toc-fg);
  outline-offset: 2px;
}

.kodza-toc__ring svg {
  display: block;
  width: 20px;
  height: 20px;
  transform: rotate(-90deg);
}

.kodza-toc__ring circle {
  fill: none;
  stroke-width: 2.4;
}

.kodza-toc__ring-track {
  stroke: var(--kz-toc-line);
}

.kodza-toc__ring-fill {
  stroke: var(--kz-toc-ink);
  stroke-dasharray: 1;
  stroke-dashoffset: calc(1 - var(--kz-toc-read, 0));
  stroke-linecap: round;
}

.kodza-toc__label {
  display: grid;
  flex: 1;
  min-width: 0;
}

.kodza-toc__title,
.kodza-toc__current {
  grid-area: 1 / 1;
  overflow: hidden;
  font-size: 14px;
  font-weight: 600;
  letter-spacing: -0.01em;
  text-overflow: ellipsis;
  white-space: nowrap;
  transition: opacity 0.3s ease, transform 0.4s var(--kz-toc-ease);
}

/* Folded, the head names the section you are in */
.kodza-toc__current {
  opacity: 0;
  transform: translateY(6px);
}

.kodza-toc.is-folded .kodza-toc__title {
  opacity: 0;
  transform: translateY(-6px);
}

.kodza-toc.is-folded .kodza-toc__current:not(:empty) {
  opacity: 1;
  transform: none;
}

.kodza-toc.is-folded .kodza-toc__label:has(.kodza-toc__current:empty) .kodza-toc__title {
  opacity: 1;
  transform: none;
}

.kodza-toc__percent {
  font-family: var(--kz-toc-mono);
  font-size: 12px;
  color: var(--kz-toc-muted);
  font-variant-numeric: tabular-nums;
}

.kodza-toc__chevron {
  width: 16px;
  height: 16px;
  fill: none;
  stroke: var(--kz-toc-muted);
  stroke-width: 1.6;
  stroke-linecap: round;
  stroke-linejoin: round;
  transform: rotate(180deg);
  transition: transform var(--kz-toc-duration) var(--kz-toc-ease);
}

.kodza-toc.is-folded .kodza-toc__chevron {
  transform: none;
}

/* The body folds away by its row height: nothing jumps */
.kodza-toc__body {
  display: grid;
  grid-template-rows: 1fr;
  transition: grid-template-rows var(--kz-toc-duration) var(--kz-toc-ease);
}

.kodza-toc.is-folded .kodza-toc__body {
  grid-template-rows: 0fr;
}

.kodza-toc__inner {
  min-height: 0;
  overflow: hidden;
}

/* The list: a track, the part already read, and the marker on the current section */
.kodza-toc__list {
  position: relative;
  display: grid;
  margin: 0 18px;
  padding: 4px 0 12px 14px;
  border-top: 1px solid var(--kz-toc-line);
  list-style: none;
}

.kodza-toc__list::before,
.kodza-toc__fill,
.kodza-toc__marker {
  content: "";
  position: absolute;
  top: 12px;
  left: 0;
  width: 1px;
  height: calc(100% - 24px);
}

.kodza-toc__list::before {
  background: var(--kz-toc-line);
}

.kodza-toc__fill {
  background: var(--kz-toc-faint);
  transform: scaleY(var(--kz-toc-read, 0));
  transform-origin: top;
}

.kodza-toc__marker {
  top: 0;
  left: -0.5px;
  width: 2px;
  height: 1px;
  border-radius: 2px;
  background: var(--kz-toc-ink);
  opacity: var(--kz-toc-on, 0);
  transform: translateY(var(--kz-toc-y, 0)) scaleY(var(--kz-toc-h, 0));
  transform-origin: top;
}

.kodza-toc.is-live .kodza-toc__marker {
  transition: transform var(--kz-toc-duration) var(--kz-toc-ease), opacity 0.3s ease;
}

.kodza-toc__link {
  display: flex;
  gap: 10px;
  padding: 7px 0;
  border-radius: 6px;
  color: var(--kz-toc-muted);
  font-size: 14px;
  font-weight: 500;
  line-height: 1.4;
  text-decoration: none;
  transition: color 0.3s ease, transform 0.4s var(--kz-toc-ease);
}

.kodza-toc__link:hover {
  color: var(--kz-toc-fg);
}

.kodza-toc__link[aria-current="true"] {
  color: var(--kz-toc-fg);
  transform: translateX(3px);
}

.kodza-toc__num {
  flex-shrink: 0;
  width: 2ch;
  padding-top: 1px;
  font-family: var(--kz-toc-mono);
  font-size: 11px;
}

.kodza-toc__item--sub .kodza-toc__link {
  padding-left: calc(2ch + 10px);
  font-weight: 400;
}

/* The foot: the time left, and a way back up once you are in */
.kodza-toc__foot {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin: 0 18px;
  padding: 12px 0 16px;
  border-top: 1px solid var(--kz-toc-line);
  font-family: var(--kz-toc-mono);
  font-size: 12px;
  color: var(--kz-toc-muted);
}

.kodza-toc__top {
  padding: 4px 0;
  border: 0;
  border-radius: 4px;
  background: none;
  color: var(--kz-toc-fg);
  font: inherit;
  cursor: pointer;
  opacity: 0;
  transform: translateY(4px);
  visibility: hidden;
  transition: opacity 0.3s ease, transform 0.4s var(--kz-toc-ease), visibility 0s linear 0.4s;
}

.kodza-toc.is-in .kodza-toc__top {
  opacity: 1;
  transform: none;
  visibility: visible;
  transition-delay: 0s;
}

/* Small screens: a bar at the top of the screen, folded until tapped */
@media (max-width: 900px) {
  .kodza-toc {
    top: 12px;
    z-index: 20;
    box-shadow: inset 0 0 0 1px var(--kz-toc-line), 0 10px 30px -12px rgba(10, 10, 10, 0.2);
  }

  .kodza-toc__inner {
    max-height: 60vh;
    overflow-y: auto;
  }
}

@media (prefers-reduced-motion: reduce) {
  .kodza-toc.is-live .kodza-toc__marker,
  .kodza-toc__link,
  .kodza-toc__title,
  .kodza-toc__current,
  .kodza-toc__chevron,
  .kodza-toc__body,
  .kodza-toc__top {
    transition-duration: 0.01ms !important;
    transition-delay: 0s !important;
  }
}

/* Theming example — on a dark background:
.dark-section .kodza-toc {
  --kz-toc-bg: #161616;
  --kz-toc-fg: #f2f2f0;
  --kz-toc-muted: rgba(242, 242, 240, 0.6);
  --kz-toc-faint: rgba(242, 242, 240, 0.4);
  --kz-toc-line: rgba(255, 255, 255, 0.1);
  --kz-toc-ink: #f2f2f0;
}
*/

/* kodza-guard a34adb4d90d9 — 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, where the component sets it only in some states: at the lowest weight, so its own rules below put it back */

:where(.kodza-toc__head):not(#_),
:where(.kodza-toc__link):not(#_),
:where(.kodza-toc__top):not(#_) {
  outline: revert;
  outline-offset: revert;
}

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

.kodza-toc:not(#_) {
  border: revert;
  padding: revert;
  outline: revert;
  text-decoration: revert;
  transition: revert;
  list-style: revert;
  box-sizing: revert;
  outline-offset: revert;
  appearance: revert;
  max-height: 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-toc__head:not(#_) {
  margin: revert;
  text-decoration: revert;
  transition: revert;
  list-style: revert;
  box-sizing: revert;
  float: revert;
  position: revert;
  box-shadow: revert;
  appearance: revert;
  max-width: revert;
  max-height: revert;
  letter-spacing: revert;
  text-transform: revert;
  text-underline-offset: revert;
  text-indent: revert;
  text-shadow: revert;
  vertical-align: revert;
  white-space: revert;
  min-height: revert;
}

.kodza-toc__ring:not(#_),
.kodza-toc__ring-track:not(#_),
.kodza-toc__ring-fill:not(#_),
.kodza-toc__label:not(#_),
.kodza-toc__title:not(#_),
.kodza-toc__current:not(#_),
.kodza-toc__percent:not(#_),
.kodza-toc__body:not(#_),
.kodza-toc__inner:not(#_),
.kodza-toc__fill:not(#_),
.kodza-toc__marker:not(#_),
.kodza-toc__num:not(#_),
.kodza-toc__foot:not(#_),
.kodza-toc__left:not(#_) {
  box-sizing: revert;
}

.kodza-toc__chevron:not(#_) {
  border: revert;
  margin: revert;
  padding: revert;
  border-radius: revert;
  outline: revert;
  text-decoration: 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-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-toc__list:not(#_) {
  border-radius: revert;
  outline: revert;
  text-decoration: revert;
  transition: revert;
  box-sizing: revert;
  float: revert;
  border-right-width: revert;
  border-bottom-width: revert;
  border-left-width: revert;
  border-right-style: revert;
  border-bottom-style: revert;
  border-left-style: revert;
  border-right-color: revert;
  border-bottom-color: revert;
  border-left-color: 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-toc__item:not(#_),
.kodza-toc__ring svg:where(:not([class*="kodza-"])):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;
  position: 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-toc__link:not(#_) {
  border: revert;
  margin: revert;
  list-style: revert;
  box-sizing: revert;
  float: revert;
  position: revert;
  background-color: revert;
  background-image: revert;
  box-shadow: revert;
  appearance: revert;
  max-width: revert;
  max-height: revert;
  font-family: revert;
  font-style: revert;
  letter-spacing: revert;
  text-transform: revert;
  text-underline-offset: revert;
  text-align: revert;
  text-indent: revert;
  text-shadow: revert;
  vertical-align: revert;
}

.kodza-toc__top:not(#_) {
  margin: revert;
  text-decoration: revert;
  list-style: revert;
  box-sizing: revert;
  float: revert;
  position: revert;
  box-shadow: revert;
  appearance: revert;
  max-width: revert;
  max-height: revert;
  letter-spacing: revert;
  text-transform: revert;
  text-underline-offset: revert;
  text-align: revert;
  text-indent: revert;
  text-shadow: revert;
  vertical-align: revert;
  white-space: revert;
  min-height: revert;
}

.kodza-toc:not(#_):where(:not([hidden])),
.kodza-toc__chevron:not(#_):where(:not([hidden])),
.kodza-toc__item:not(#_):where(:not([hidden])),
.kodza-toc__top:not(#_):where(:not([hidden])) {
  display: revert;
}

.kodza-toc:not(#_):where([hidden]),
.kodza-toc__chevron:not(#_):where([hidden]),
.kodza-toc__item:not(#_):where([hidden]),
.kodza-toc__top:not(#_):where([hidden]) {
  display: none;
}

.kodza-toc__list:not(#_)::before {
  box-sizing: revert;
}

/* 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-toc:not(#_) {
  position: sticky;
  border-radius: 16px;
  background: var(--kz-toc-bg);
  box-shadow: inset 0 0 0 1px var(--kz-toc-line);
  color: var(--kz-toc-fg);
}

.kodza-toc__head:not(#_) {
  display: flex;
  align-items: center;
  gap: 10px;
  width: 100%;
  padding: 16px 18px;
  border: 0;
  border-radius: 16px;
  background: none;
  color: inherit;
  font: inherit;
  text-align: left;
  cursor: pointer;
}

.kodza-toc__head:focus-visible:not(#_),
.kodza-toc__top:focus-visible:not(#_) {
  outline: 2px solid var(--kz-toc-fg);
  outline-offset: 2px;
}

.kodza-toc__link:focus-visible:not(#_) {
  outline: 2px solid var(--kz-toc-fg);
  outline-offset: 2px;
}

.kodza-toc__ring svg:not(#_) {
  display: block;
}

.kodza-toc__chevron:not(#_) {
  transition: transform var(--kz-toc-duration) var(--kz-toc-ease);
}

.kodza-toc__list:not(#_) {
  position: relative;
  display: grid;
  margin: 0 18px;
  padding: 4px 0 12px 14px;
  border-top: 1px solid var(--kz-toc-line);
  list-style: none;
}

.kodza-toc__link:not(#_) {
  display: flex;
  padding: 7px 0;
  border-radius: 6px;
  color: var(--kz-toc-muted);
  font-size: 14px;
  font-weight: 500;
  line-height: 1.4;
  text-decoration: none;
  transition: color 0.3s ease, transform 0.4s var(--kz-toc-ease);
}

.kodza-toc__link:hover:not(#_) {
  color: var(--kz-toc-fg);
}

.kodza-toc__link[aria-current="true"]:not(#_) {
  color: var(--kz-toc-fg);
}

.kodza-toc__item--sub .kodza-toc__link:not(#_) {
  padding-left: calc(2ch + 10px);
  font-weight: 400;
}

.kodza-toc__top:not(#_) {
  padding: 4px 0;
  border: 0;
  border-radius: 4px;
  background: none;
  color: var(--kz-toc-fg);
  font: inherit;
  cursor: pointer;
  opacity: 0;
  transform: translateY(4px);
  visibility: hidden;
  transition: opacity 0.3s ease, transform 0.4s var(--kz-toc-ease), visibility 0s linear 0.4s;
}

.kodza-toc.is-in .kodza-toc__top:not(#_) {
  opacity: 1;
  transform: none;
  visibility: visible;
  transition-delay: 0s;
}

@media (max-width: 900px) {
  .kodza-toc:not(#_) {
    box-shadow: inset 0 0 0 1px var(--kz-toc-line), 0 10px 30px -12px rgba(10, 10, 10, 0.2);
  }
}

@media (prefers-reduced-motion: reduce) {
  .kodza-toc__link:not(#_),
  .kodza-toc__chevron:not(#_) {
    transition-duration: 0.01ms !important;
    transition-delay: 0s !important;
  }
}

@media (prefers-reduced-motion: reduce) {
  .kodza-toc__top:not(#_) {
    transition-duration: 0.01ms !important;
    transition-delay: 0s !important;
  }
}
```

```js
// Kodza License: free to use, client work included. Not to resell or redistribute, ported or not: https://kodza.dev/docs/#print-license
// Kodza — Table of Contents
// Builds the list from the headings of the article next to it (data-target, or the nearest
// article / main / .entry-content), gives them ids if they have none, and follows the reading:
// current section, progress ring and percentage, time left, "Back to top". The head folds the
// list away (folded from the start on small screens, where the head names the current section).
(() => {
  const SELECTOR = '.kodza-toc';
  const reduceMotion = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  const small = window.matchMedia('(max-width: 900px)');
  const slug = (text) => text.toLowerCase().normalize('NFD').replace(/[̀-ͯ]/g, '').replace(/[^a-z0-9]+/g, '-').replace(/^-|-$/g, '') || 'section';
  const WORDS_PER_MINUTE = 220;

  // One instance. Everything it starts is tied to `signal`, so kodza:destroy stops it all
  function mount(root, signal) {
    const list = root.querySelector('.kodza-toc__list');
    const head = root.querySelector('.kodza-toc__head');
    const current = root.querySelector('.kodza-toc__current');
    const percent = root.querySelector('.kodza-toc__percent');
    const left = root.querySelector('.kodza-toc__left');
    const top = root.querySelector('.kodza-toc__top');
    const selector = root.dataset.target || 'article, main, .entry-content';
    // The closest article around (or beside) the summary
    let scope = root.parentElement;
    while (scope && !scope.querySelector(selector)) scope = scope.parentElement;
    const article = scope?.querySelector(selector);
    if (!list || !article) return;
    const headings = [...article.querySelectorAll(root.dataset.headings || 'h2, h3')];
    if (!headings.length) return;
    const minutes = Math.max(1, Math.round(article.textContent.trim().split(/\s+/).length / WORDS_PER_MINUTE));
    const offset = () => parseFloat(getComputedStyle(root).getPropertyValue('--kz-toc-offset')) || 0;
    const goTo = (y) => window.scrollTo({ top: y, behavior: reduceMotion ? 'auto' : 'smooth' });

    let number = 0;
    const named = []; // the headings given an id here, which lose it again on abort
    const links = headings.map((heading) => {
      if (!heading.id) {
        let id = slug(heading.textContent);
        for (let n = 2; document.getElementById(id); n++) id = `${slug(heading.textContent)}-${n}`;
        heading.id = id;
        named.push(heading);
      }
      const sub = heading.tagName === 'H3';
      const item = document.createElement('li');
      item.className = `kodza-toc__item${sub ? ' kodza-toc__item--sub' : ''}`;
      const link = document.createElement('a');
      link.className = 'kodza-toc__link';
      link.href = `#${heading.id}`;
      if (!sub) {
        const num = document.createElement('span');
        num.className = 'kodza-toc__num';
        num.setAttribute('aria-hidden', 'true');
        num.textContent = String(++number).padStart(2, '0');
        link.append(num);
      }
      link.append(heading.textContent);
      link.addEventListener('click', (event) => {
        event.preventDefault();
        goTo(heading.getBoundingClientRect().top + window.scrollY - offset());
        history.replaceState(null, '', `#${heading.id}`);
        if (small.matches) fold(true);
      }, { signal });
      item.append(link);
      return link;
    });
    signal.addEventListener('abort', () => named.forEach((heading) => heading.removeAttribute('id')));

    const fill = document.createElement('span');
    const marker = document.createElement('span');
    fill.className = 'kodza-toc__fill';
    marker.className = 'kodza-toc__marker';
    fill.setAttribute('aria-hidden', 'true');
    marker.setAttribute('aria-hidden', 'true');
    list.replaceChildren(fill, marker, ...links.map((link) => link.parentElement));

    const fold = (on) => {
      root.classList.toggle('is-folded', on);
      head?.setAttribute('aria-expanded', String(!on));
    };
    head?.addEventListener('click', () => fold(!root.classList.contains('is-folded')), { signal });
    top?.addEventListener('click', () => goTo(article.getBoundingClientRect().top + window.scrollY - offset()), { signal });

    let active = -2;
    const update = () => {
      // The section being read: the last heading above the top third of the screen
      const line = innerHeight * 0.3;
      let index = -1;
      headings.forEach((heading, i) => {
        if (heading.getBoundingClientRect().top <= line) index = i;
      });
      const box = article.getBoundingClientRect();
      const read = Math.min(1, Math.max(0, (line - box.top) / Math.max(1, box.height - innerHeight * 0.5)));
      root.style.setProperty('--kz-toc-read', read.toFixed(4));
      if (percent) percent.textContent = `${Math.round(read * 100)}%`;
      if (left) left.textContent = read > 0.98 ? 'All read' : `${Math.max(1, Math.ceil(minutes * (1 - read)))} min left`;
      root.classList.toggle('is-in', read > 0.08);
      if (index === active) return;
      active = index;
      links.forEach((link, i) => link.setAttribute('aria-current', String(i === index)));
      const link = links[index];
      if (current) current.textContent = link ? link.lastChild.textContent : '';
      root.style.setProperty('--kz-toc-on', link ? 1 : 0);
      if (link) {
        root.style.setProperty('--kz-toc-y', `${link.parentElement.offsetTop}px`);
        root.style.setProperty('--kz-toc-h', link.parentElement.offsetHeight);
      }
    };

    let ticking = false;
    window.addEventListener('scroll', () => {
      if (ticking) return;
      ticking = true;
      requestAnimationFrame(() => {
        if (signal.aborted) return;
        ticking = false;
        update();
      });
    }, { passive: true, signal });
    window.addEventListener('resize', () => {
      active = -2;
      update();
    }, { signal });
    small.addEventListener?.('change', (event) => fold(event.matches), { signal });

    fold(small.matches);
    update();
    requestAnimationFrame(() => !signal.aborted && root.classList.add('is-live'));
  }

  // 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.
  const instances = new WeakMap();
  const find = (scope = document) => [scope, ...scope.querySelectorAll(SELECTOR)].filter((el) => el.matches?.(SELECTOR));
  const init = (scope) => find(scope).forEach((root) => {
    if (root.classList.contains('is-ready')) return; // already running, maybe from another copy of this script
    const controller = new AbortController();
    instances.set(root, { controller, html: root.innerHTML, attrs: [...root.attributes].map((a) => [a.name, a.value]) });
    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.controller.abort();
    [...root.attributes].forEach((a) => root.removeAttribute(a.name));
    instance.attrs.forEach(([name, value]) => root.setAttribute(name, value));
    root.innerHTML = instance.html;
  });
  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).