# Scroll Reveal

> Blocks make their entrance as they scroll in: a fade, lines rising from a mask, or an image unveiled by clip-path. Blocks that arrive together take turns.

Scroll · scroll, reveal, mask, clip-path · HTML, CSS, vanilla JS · no dependencies · updated 2026-10-16
Demo: https://kodza.dev/components/fade-in-scroll/

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-fade-in-scroll.css`](https://kodza.dev/registry/fade-in-scroll/kodza-fade-in-scroll.css) · 6.5 KB
- [`kodza-fade-in-scroll.js`](https://kodza.dev/registry/fade-in-scroll/kodza-fade-in-scroll.js) · 6.0 KB
- [`kodza-fade-in-scroll.html`](https://kodza.dev/registry/fade-in-scroll/kodza-fade-in-scroll.html) · 1.3 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-fade-in-scroll.css https://kodza.dev/registry/fade-in-scroll/kodza-fade-in-scroll.css
curl -fsSL --create-dirs -o kodza/kodza-fade-in-scroll.js https://kodza.dev/registry/fade-in-scroll/kodza-fade-in-scroll.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-reveal`
- Variables (set them on the root element itself: it declares its own defaults):
  - `--kz-reveal-distance: 28px`
  - `--kz-reveal-duration: 0.9s`
  - `--kz-reveal-ease: cubic-bezier(0.22, 1, 0.36, 1)`
  - `--kz-reveal-stagger: 90ms`
  - `--kz-reveal-radius: 16px`
- Modifiers: `.kodza-reveal--clip`, `.kodza-reveal--mask`, `.kodza-reveal--repeat`
- 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-reveal-sample__label,
  .kodza-reveal-sample figcaption {
    color: rgba(242, 242, 240, 0.62);
  }

  .kodza-reveal-sample__text {
    color: rgba(242, 242, 240, 0.62);
  }
}
```

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

Its images have dark versions next to them (`kz-steps-2400.webp` → `kz-steps-dark-2400.webp`). To swap them on a dark page: `<picture><source media="(prefers-color-scheme: dark)" srcset="…-dark-….webp"><img …></picture>`.

## Use it

### Plain HTML page

- CSS: `kodza/kodza-fade-in-scroll.css` next to the page (the Files commands as they are), linked in `<head>`: `<link rel="stylesheet" href="kodza/kodza-fade-in-scroll.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-fade-in-scroll.js`, loaded with `<script src="kodza/kodza-fade-in-scroll.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$/{r kodza/kodza-fade-in-scroll.css' -e 'd' -e '}' -e '/^KODZA-JS$/{r kodza/kodza-fade-in-scroll.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">`.
- Images: the artifact blocks every other host, `kodza.dev` included, without an error. Embed each one as a `data:` URI, with a command if you can run one (`curl -s <url> | base64`; the 1400 px files weigh 10 to 30 KB), never by typing base64 out. If you can't run commands, keep the `<img>` with its `width` and `height`, and tell the user the picture stays blank inside the artifact.
- 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.
- 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-fade-in-scroll', $uri . 'kodza-fade-in-scroll.css', [], filemtime($dir . 'kodza-fade-in-scroll.css'));
    wp_enqueue_script('kodza-fade-in-scroll', $uri . 'kodza-fade-in-scroll.js', [], filemtime($dir . 'kodza-fade-in-scroll.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.
- 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-fade-in-scroll.css` and `assets/kodza-fade-in-scroll.js` (the Files commands with `-o assets/…`).
- In the section: `{{ 'kodza-fade-in-scroll.css' | asset_url | stylesheet_tag }}` and `<script src="{{ 'kodza-fade-in-scroll.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/`): `ScrollReveal.tsx` (below), the CSS block under Code saved as `fade-in-scroll.css` and the JS block as `fade-in-scroll.js`, both as they are. The HTML block is already inside the component: skip it.
- Use it: `import { ScrollReveal } from '@/components/kodza/ScrollReveal';` then `<ScrollReveal>01 · Entrances</ScrollReveal>`. Props: `variant` ("clip", "mask", "repeat", or several in an array), `vars` (the `--kz-…` variables listed under API, e.g. `vars={{ '--kz-reveal-distance': … }}`), `children` (the text, plain), `className`, `style` and the other props of its `<p>` (`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 './fade-in-scroll.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 — Scroll Reveal, for React. From https://kodza.dev/components/fade-in-scroll/
// 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: fade-in-scroll.css and fade-in-scroll.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 './fade-in-scroll.css';

type Variant = "clip" | "mask" | "repeat";

export type ScrollRevealProps = Omit<ComponentPropsWithoutRef<'p'>, "children" | "variant" | "vars"> & {
  /** Modifier class(es): .kodza-reveal--clip, .kodza-reveal--mask, .kodza-reveal--repeat */
  variant?: Variant | Variant[];
  /** Settings, as CSS variables on the root */
  vars?: {
    /** default: 28px */
    "--kz-reveal-distance"?: string | number;
    /** default: 0.9s */
    "--kz-reveal-duration"?: string | number;
    /** default: cubic-bezier(0.22, 1, 0.36, 1) */
    "--kz-reveal-ease"?: string | number;
    /** default: 90ms */
    "--kz-reveal-stagger"?: string | number;
    /** default: 16px */
    "--kz-reveal-radius"?: string | number;
  };
  /** The text, plain: the script reads it and rebuilds the markup around it */
  children?: string;
  className?: string;
};

export function ScrollReveal({ variant, vars, children = "01 · Entrances", className, style, ...rest }: ScrollRevealProps) {
  const ref = useRef<ComponentRef<'p'>>(null);
  const classes = ["kodza-reveal", ...([] as string[]).concat(variant ?? []).map((v) => `kodza-reveal--${v}`), 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, 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('./fade-in-scroll.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 (
    <p key={key} {...rest} className={classes} style={{ ...vars, ...style } as CSSProperties} ref={ref}>{children}</p>
  );
}
```

## Code

```html
<section class="kodza-reveal-sample">
  <p class="kodza-reveal kodza-reveal-sample__label">01 · Entrances</p>
  <h2 class="kodza-reveal kodza-reveal--mask kodza-reveal-sample__title">Things show up when you get there, not a second before.</h2>
  <p class="kodza-reveal kodza-reveal-sample__text">Fade, mask or clip: one class per block picks the entrance. Blocks that arrive together take turns, the others do not wait.</p>
  <div class="kodza-reveal kodza-reveal--clip kodza-reveal-sample__wide">
    <img src="https://kodza.dev/media/kz-steps-2400.webp" alt="Concrete steps climbing into a pale wall">
  </div>
  <div class="kodza-reveal-sample__row">
    <figure>
      <div class="kodza-reveal kodza-reveal--clip"><img src="https://kodza.dev/media/kz-block-1400.webp" alt="A concrete block"></div>
      <figcaption class="kodza-reveal">display: block</figcaption>
    </figure>
    <figure>
      <div class="kodza-reveal kodza-reveal--clip"><img src="https://kodza.dev/media/kz-stack-1400.webp" alt="Stacked concrete slabs"></div>
      <figcaption class="kodza-reveal">z-index: 9999</figcaption>
    </figure>
    <figure>
      <div class="kodza-reveal kodza-reveal--clip"><img src="https://kodza.dev/media/kz-float-1400.webp" alt="A floating concrete slab"></div>
      <figcaption class="kodza-reveal">position: absolute</figcaption>
    </figure>
  </div>
</section>
```

```css
/* Kodza License: free to use, client work included. Not to resell or redistribute, ported or not: https://kodza.dev/docs/#print-license */
/* Kodza — Scroll Reveal
   Blocks make their entrance as they scroll into view. One class per block picks it:
   .kodza-reveal                 fades in and rises
   .kodza-reveal--mask           text: each line rises from behind its own mask
   .kodza-reveal--clip           a box (image inside): unveiled from the top, the image settling
   .kodza-reveal--repeat         plays again each time it comes back from below
   Blocks that arrive together take turns; a block arriving alone does not wait. Without JS or
   with reduced motion, everything is simply there. The sample markup is only an example: put
   the classes on your own blocks.
   Everything is tuned with the --kz-reveal-* variables. */
.kodza-reveal {
  --kz-reveal-distance: 28px;
  --kz-reveal-duration: 0.9s;
  --kz-reveal-ease: cubic-bezier(0.22, 1, 0.36, 1);
  --kz-reveal-stagger: 90ms;
  --kz-reveal-radius: 16px;
}

/* Fade: armed by the script, then in (with no entrance when already scrolled past: is-instant) */
.kodza-reveal.is-armed:not(.kodza-reveal--mask):not(.kodza-reveal--clip) {
  opacity: 0;
  transform: translateY(var(--kz-reveal-distance));
}

.kodza-reveal.is-armed.is-in:not(.kodza-reveal--mask):not(.kodza-reveal--clip) {
  opacity: 1;
  transform: none;
}

.kodza-reveal.is-armed.is-in:not(.is-instant):not(.kodza-reveal--mask):not(.kodza-reveal--clip) {
  transition:
    opacity calc(var(--kz-reveal-duration) * 0.8) ease calc(var(--i, 0) * var(--kz-reveal-stagger)),
    transform var(--kz-reveal-duration) var(--kz-reveal-ease) calc(var(--i, 0) * var(--kz-reveal-stagger));
}

/* Mask: each line in its own window */
.kodza-reveal__line {
  display: block;
  overflow: hidden;
  padding-bottom: 0.1em;
  margin-bottom: -0.1em;
}

.kodza-reveal__line > span {
  display: block;
}

.kodza-reveal.is-armed .kodza-reveal__line > span {
  transform: translateY(110%);
}

.kodza-reveal.is-armed.is-in .kodza-reveal__line > span {
  transform: none;
}

.kodza-reveal.is-armed.is-in:not(.is-instant) .kodza-reveal__line > span {
  transition: transform calc(var(--kz-reveal-duration) * 1.1) var(--kz-reveal-ease) calc((var(--i, 0) + var(--kz-line, 0)) * var(--kz-reveal-stagger));
}

/* Clip: the box opens from the top, the image inside settles from a slight zoom */
.kodza-reveal--clip {
  overflow: hidden;
  border-radius: var(--kz-reveal-radius);
}

.kodza-reveal--clip > img {
  display: block;
  width: 100%;
  height: auto;
}

.kodza-reveal--clip.is-armed {
  clip-path: inset(0 0 100% 0 round var(--kz-reveal-radius));
}

.kodza-reveal--clip.is-armed > img {
  transform: scale(1.14);
}

.kodza-reveal--clip.is-armed.is-in {
  clip-path: inset(0 0 0 0 round var(--kz-reveal-radius));
}

.kodza-reveal--clip.is-armed.is-in:not(.is-instant) {
  transition: clip-path calc(var(--kz-reveal-duration) * 1.2) cubic-bezier(0.65, 0, 0.35, 1) calc(var(--i, 0) * var(--kz-reveal-stagger));
}

.kodza-reveal--clip.is-armed.is-in > img {
  transform: none;
}

.kodza-reveal--clip.is-armed.is-in:not(.is-instant) > img {
  transition: transform calc(var(--kz-reveal-duration) * 1.9) var(--kz-reveal-ease) calc(var(--i, 0) * var(--kz-reveal-stagger));
}

@media (prefers-reduced-motion: reduce) {
  .kodza-reveal.is-armed,
  .kodza-reveal.is-armed .kodza-reveal__line > span,
  .kodza-reveal--clip.is-armed > img {
    transition: none !important;
  }
}

/* kodza-guard 974609b64736 — 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-reveal img:where(:not([class*="kodza-"]))):not(#_) {
  transition: revert;
}

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

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

.kodza-reveal__line:not(#_),
.kodza-reveal__line span:where(:not([class*="kodza-"])):not(#_) {
  box-sizing: revert;
}

.kodza-reveal img:where(:not([class*="kodza-"])):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-reveal:not(#_):where(:not([hidden])) {
  display: revert;
}

.kodza-reveal: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-reveal.is-armed.is-in:not(.is-instant):not(.kodza-reveal--mask):not(.kodza-reveal--clip):where(p, h2, figcaption):not(#_) {
  transition: opacity calc(var(--kz-reveal-duration) * 0.8) ease calc(var(--i, 0) * var(--kz-reveal-stagger)),
    transform var(--kz-reveal-duration) var(--kz-reveal-ease) calc(var(--i, 0) * var(--kz-reveal-stagger));
}

.kodza-reveal--clip > img:not(#_) {
  display: block;
}

.kodza-reveal--clip.is-armed.is-in:not(.is-instant) > img:not(#_) {
  transition: transform calc(var(--kz-reveal-duration) * 1.9) var(--kz-reveal-ease) calc(var(--i, 0) * var(--kz-reveal-stagger));
}

@media (prefers-reduced-motion: reduce) {
  .kodza-reveal.is-armed:where(p, h2, figcaption):not(#_),
  .kodza-reveal--clip.is-armed > img:not(#_) {
    transition: none !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 — Scroll Reveal
// Arms every .kodza-reveal (hidden state), then plays its entrance when it scrolls into view.
// Blocks entering together get a turn each (by position, top to bottom, left to right); a block
// entering alone starts at once. Mask blocks are cut into lines at their current width, and
// given back their original text once in, so a later resize reflows them normally.
(() => {
  const SELECTOR = '.kodza-reveal';
  const reduceMotion = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  const blocks = new WeakMap(); // block → { text (mask blocks: their plain text), signal }

  // Cut a text block into lines, each in its own window (plain text only)
  const split = (el, text) => {
    el.textContent = '';
    const spans = text.split(/\s+/).map((word) => {
      const span = document.createElement('span');
      span.textContent = `${word} `;
      el.append(span);
      return span;
    });
    const lines = [];
    spans.forEach((span) => {
      const last = lines[lines.length - 1];
      if (last && Math.abs(last.top - span.offsetTop) < 2) last.words.push(span.textContent);
      else lines.push({ top: span.offsetTop, words: [span.textContent] });
    });
    el.textContent = '';
    lines.forEach((line, i) => {
      const outer = document.createElement('span');
      const inner = document.createElement('span');
      outer.className = 'kodza-reveal__line';
      inner.textContent = line.words.join('').trim();
      inner.style.setProperty('--kz-line', i);
      outer.append(inner);
      el.append(outer, ' ');
    });
  };

  const reveal = (el, i, instant) => {
    el.style.setProperty('--i', i);
    el.classList.toggle('is-instant', instant);
    el.classList.add('is-in');
    if (instant) requestAnimationFrame(() => requestAnimationFrame(() => el.classList.remove('is-instant')));
    // Once a mask has played, it gets its plain text back
    const { text, signal } = blocks.get(el);
    if (text !== null && !el.classList.contains('kodza-reveal--repeat')) {
      const duration = parseFloat(getComputedStyle(el).getPropertyValue('--kz-reveal-duration')) || 0.9;
      const lines = el.querySelectorAll('.kodza-reveal__line').length;
      const timer = setTimeout(() => (el.textContent = text), instant ? 0 : (duration * 1.1 + 0.09 * (i + lines)) * 1000 + 100);
      signal.addEventListener('abort', () => clearTimeout(timer));
    }
  };

  // One observer for every block, so the blocks entering together take turns
  let observer = null;
  const watch = (entries) => {
    const arriving = [];
    entries.forEach((entry) => {
      const el = entry.target;
      if (entry.isIntersecting) {
        if (!el.classList.contains('is-in')) arriving.push(entry);
      } else if (entry.boundingClientRect.top < 0) {
        // Scrolled past it (or loaded below it): it is simply there
        if (!el.classList.contains('is-in')) reveal(el, 0, true);
      } else if (el.classList.contains('kodza-reveal--repeat')) {
        el.classList.remove('is-in');
      }
    });
    arriving
      .sort((a, b) => a.boundingClientRect.top - b.boundingClientRect.top || a.boundingClientRect.left - b.boundingClientRect.left)
      .forEach((entry, i) => reveal(entry.target, i, false));
    entries.forEach((entry) => {
      if (entry.target.classList.contains('is-in') && !entry.target.classList.contains('kodza-reveal--repeat')) observer.unobserve(entry.target);
    });
  };

  // One instance. Everything it starts is tied to `signal`, so kodza:destroy stops it all
  function mount(el, signal) {
    if (reduceMotion || !('IntersectionObserver' in window)) return;
    const mask = el.classList.contains('kodza-reveal--mask') && !el.children.length;
    const text = mask ? el.textContent.trim() : null;
    blocks.set(el, { text, signal });
    if (mask) {
      split(el, text);
      document.fonts?.ready.then(() => !signal.aborted && !el.classList.contains('is-in') && split(el, text));
      let width = innerWidth;
      window.addEventListener('resize', () => {
        if (innerWidth === width) return;
        width = innerWidth;
        if (!el.classList.contains('is-in')) split(el, text);
      }, { signal });
    }
    el.classList.add('is-armed');
    observer ||= new IntersectionObserver(watch, { rootMargin: '0px 0px -12% 0px' });
    observer.observe(el);
    signal.addEventListener('abort', () => observer.unobserve(el));
  }

  // 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).