# One worksheet in ten school traditions

> The same seven :::exercise fences in ten languages, each edition printed by an exercise style set the way that country's school books set exercises.

- HTML version: https://postext.dev/en/cookbook/school-traditions-worksheet
- Recipe Nº 169 · Textbooks · Level 2 (Intermediate) · Outputs: Canvas, PDF
- Genres: Workbooks & exercises, Textbooks
- Requires postext ≥ 1.59.0, postext-pdf ≥ 1.59.0 · tested with 1.59.0, postext-pdf 1.59.0 on 2026-10-24
- Pages: [1](https://postext.dev/cookbook/school-traditions-worksheet/en/p01.webp?v=89d140be), [2](https://postext.dev/cookbook/school-traditions-worksheet/en/p02.webp?v=89d140be)
- PDF: https://postext.dev/cookbook/school-traditions-worksheet/en/school-traditions-worksheet.pdf?v=89d140be
- Open in Sandbox: https://postext.dev/en/sandbox#recipe=school-traditions-worksheet&lang=en (.postext: https://postext.dev/cookbook/school-traditions-worksheet/en/school-traditions-worksheet.postext)
- Last updated: 2026-10-24
- Other languages: [es](https://postext.dev/es/cookbook/school-traditions-worksheet.md), [ca](https://postext.dev/ca/cookbook/school-traditions-worksheet.md), [de](https://postext.dev/de/cookbook/school-traditions-worksheet.md), [fr](https://postext.dev/fr/cookbook/school-traditions-worksheet.md), [it](https://postext.dev/it/cookbook/school-traditions-worksheet.md), [pt](https://postext.dev/pt/cookbook/school-traditions-worksheet.md), [zh](https://postext.dev/zh/cookbook/school-traditions-worksheet.md), [ja](https://postext.dev/ja/cookbook/school-traditions-worksheet.md), [ar](https://postext.dev/ar/cookbook/school-traditions-worksheet.md)

## In short

A two-page science and maths worksheet about the water cycle, made ten times. The questions are the same; the numbers, the answer boxes, the lines to write on and the long division look the way each country's schoolbooks print them.

## What you'll build

Worksheet 7 of a Year 4 science and maths course, *Water on the move*, in ten editions. The questions are the same in every language: choose an answer, tick true or false, fill the gaps from a word bank, join words to their meanings, circle a word, divide the water in a tank, explain why to save it. Each edition prints them as its schools do. The Spanish and Catalan sheets put the number in a disc, tick V or F and divide with the divisor in an L to the right of the dividend. The French one uses squares, *cases à cocher*, dotted blanks and Seyès paper for the answer. The German one writes *R* and *F*, *Lückentext* and `864 : 4 =` on one line, the multiplication with a dot. The Brazilian one asks for V or F in brackets. The English one divides under the ⟌ bracket. The Chinese sheet numbers its sections 一、二、, puts （　） after each stem with A. B. C. in a row, asks for √ or × and ends with 看拼音，写词语 on 田字格 squares. The Japanese one offers ア イ ウ and ○ ×, the Arabic one runs right to left with أ ب ج and صح or خطأ.

**This recipe answers:**

- How do I set the same worksheet the way each country's school books set their exercises?
- How do I set long division the way each country's schools write it?
- How do I set Chinese test questions: a （　） bracket after the stem and A. B. C. D. options in a row?

## The short answer

The form of the exercises, as each country's school books set them.

```js
// script.js, lines 36–69
// The Markdown of every edition has the same seven exercises. What changes is this table:
// how the number prints, how options are labelled and answered, how true/false reads, where
// a blank is written, the paper of the open answer and the layout of long division.
const disc = { shape: 'disc' };
const square = { shape: 'square' };
const bare = { shape: 'none', suffix: '.' };
const TRADITIONS = {
  es: { number: disc, options: { marker: 'none' }, trueFalse: { look: 'boxes' },
    blank: { look: 'line' }, area: { kind: 'lines' }, arithmetic: { division: 'potence' } },
  fr: { number: square, options: { marker: 'box' }, trueFalse: { look: 'boxes' },
    blank: { look: 'dots' }, area: { kind: 'seyes', spacing: mm(8) },
    arithmetic: { division: 'potence' } },
  de: { number: square, options: { marker: 'box' }, trueFalse: { look: 'boxes' },
    blank: { look: 'line' }, area: { kind: 'lines' }, arithmetic: { division: 'inline' } },
  it: { number: { shape: 'rounded' }, options: { marker: 'box' }, trueFalse: { look: 'boxes' },
    blank: { look: 'dots' }, area: { kind: 'lines' }, arithmetic: { division: 'potence' } },
  pt: { number: bare, options: { marker: 'none' }, trueFalse: { look: 'bracket' },
    blank: { look: 'line' }, area: { kind: 'lines' }, arithmetic: { division: 'potence' } },
  en: { number: bare, options: { marker: 'none' }, trueFalse: { look: 'boxes' },
    blank: { look: 'line' }, area: { kind: 'lines' }, arithmetic: { division: 'bracket' } },
  // 一、二、 sections; （　） after the stem and A. B. C. in a row; √ × in a bracket; 田字格.
  zh: { number: { shape: 'none', format: 'simp-chinese-informal', suffix: '、' },
    options: { labels: 'alpha-upper', suffix: '.', layout: 'row', bracket: true },
    trueFalse: { look: 'bracket' }, blank: { look: 'line' },
    area: { kind: 'tianzige', spacing: mm(13), lines: 1 }, arithmetic: { division: 'bracket' } },
  // ア イ ウ in a row with （　）, ○ × in a bracket, the number in a square.
  ja: { number: square, options: { labels: 'katakana', suffix: '', layout: 'row', bracket: true },
    trueFalse: { look: 'bracket' }, blank: { look: 'line' }, area: { kind: 'lines' },
    arithmetic: { division: 'bracket' } },
  ar: { number: disc, options: { marker: 'none', prefix: '(', suffix: ')' },
    trueFalse: { look: 'boxes' },
    blank: { look: 'dots' }, area: { kind: 'lines' }, arithmetic: { division: 'bracket' } },
};
TRADITIONS.ca = TRADITIONS.es; // Catalan schools set exercises as Spanish ones do
```

## Ingredients

**Teaches**

- [Exercise styles](https://postext.dev/en/docs/exercises.md#exercise-styles): exerciseStyles: how a family of exercises prints — the number (disc, square, label), the instruction, option labels, blanks, true/false boxes, dots to join, the word bank, writing areas, grids, activity icons and difficulty marks.
- [Operations in columns](https://postext.dev/en/docs/exercises.md#operations-in-columns): Operations in columns (+ − ×) with a cell for each digit, and long division set the way the language's schools set it: the bracket ⟌, the potence of Spain, France and Italy, or Germany's 864 : 4 = in a row.
- [Choice and true or false](https://postext.dev/en/docs/exercises.md#choice-and-true-or-false): Multiple choice from a task list (- [x] right, - [ ] wrong), lettered a) b) c), A. B. C., ア イ ウ or أ ب ج, with a box, a ring or a bracket to answer in; true/false statements with the language's own V F, R F, √ × or ○ ×.

**Also uses**

- [Exercises](https://postext.dev/en/docs/exercises.md#exercises)
- [Gaps and word banks](https://postext.dev/en/docs/exercises.md#gaps-and-word-banks)
- [Matching and sorting](https://postext.dev/en/docs/exercises.md#matching-and-sorting)
- [Open questions and writing areas](https://postext.dev/en/docs/exercises.md#open-questions-and-writing-areas)
- [Designed openers](https://postext.dev/en/docs/configuration-headings.md#span-and-advanced-design)
- [Heading attributes](https://postext.dev/en/docs/document-format.md#heading-attributes)
- [Semantic colour palette](https://postext.dev/en/docs/configuration-fonts-colors-viewers.md#color-palette)
- [Chinese, Japanese and Korean fonts](https://postext.dev/en/docs/configuration-pdf-output.md#chinese-japanese-and-korean-fonts)
- [Arabic fonts](https://postext.dev/en/docs/arabic-layout.md#fonts)
- [Books bound on the right](https://postext.dev/en/docs/configuration-page-layout.md#binding)
- [Right-to-left text](https://postext.dev/en/docs/arabic-layout.md#direction-and-the-bidirectional-algorithm)
- [Hyphenation and document language](https://postext.dev/en/docs/justification.md#supported-locales)
- [Pages on a canvas](https://postext.dev/en/docs/configuration-programmatic-usage.md#rendering-a-page-to-a-bitmap)
- [PDF export](https://postext.dev/en/docs/configuration-pdf-output.md#generating-pdfs)
- [Solutions](https://postext.dev/en/docs/exercises.md#solutions)
- [Paragraph styles](https://postext.dev/en/docs/configuration-styles.md#paragraph-styles)
- [Fonts embedded in the PDF](https://postext.dev/en/docs/configuration-pdf-output.md#why-a-font-provider)

**Config at a glance**

- [`bodyText`](https://postext.dev/en/docs/configuration-text.md#body-text), [`colorPalette`](https://postext.dev/en/docs/configuration-fonts-colors-viewers.md#color-palette), `exerciseStyles`, [`footer`](https://postext.dev/en/docs/configuration-headers-footers.md#headers--footers), [`header`](https://postext.dev/en/docs/configuration-headers-footers.md#headers--footers), [`headings`](https://postext.dev/en/docs/configuration-headings.md#headings), [`layout`](https://postext.dev/en/docs/configuration-page-layout.md#layout), [`locale`](https://postext.dev/en/docs/configuration-language.md#hyphenation), [`orderedLists`](https://postext.dev/en/docs/configuration-lists-math.md#ordered-lists), [`page`](https://postext.dev/en/docs/configuration-page-layout.md#page), [`paragraphStyles`](https://postext.dev/en/docs/configuration-styles.md#paragraph-styles)

**APIs**

- [`buildDocument`](https://postext.dev/en/docs/configuration-programmatic-usage.md#building-a-document), [`decompressWoff2`](https://postext.dev/en/docs/configuration-pdf-output.md#browser-font-provider-fontsource--woff2), [`renderPageToCanvas`](https://postext.dev/en/docs/configuration-programmatic-usage.md#rendering-a-page-to-a-bitmap), [`renderToPdf`](https://postext.dev/en/docs/configuration-pdf-output.md#generating-pdfs), [`withLoadedFonts`](https://postext.dev/en/docs/configuration-programmatic-usage.md#loading-fonts-before-layout)

**Typefaces**

- Nunito (OFL-1.1), Baloo 2 (OFL-1.1), Noto Serif SC (OFL-1.1), Noto Sans SC (OFL-1.1), Klee One (OFL-1.1), Noto Sans JP (OFL-1.1), Noto Naskh Arabic (OFL-1.1), Baloo Bhaijaan 2 (OFL-1.1)

## Method

### 1 · Put each tradition in a table

```js
// script.js, lines 36–69
// The Markdown of every edition has the same seven exercises. What changes is this table:
// how the number prints, how options are labelled and answered, how true/false reads, where
// a blank is written, the paper of the open answer and the layout of long division.
const disc = { shape: 'disc' };
const square = { shape: 'square' };
const bare = { shape: 'none', suffix: '.' };
const TRADITIONS = {
  es: { number: disc, options: { marker: 'none' }, trueFalse: { look: 'boxes' },
    blank: { look: 'line' }, area: { kind: 'lines' }, arithmetic: { division: 'potence' } },
  fr: { number: square, options: { marker: 'box' }, trueFalse: { look: 'boxes' },
    blank: { look: 'dots' }, area: { kind: 'seyes', spacing: mm(8) },
    arithmetic: { division: 'potence' } },
  de: { number: square, options: { marker: 'box' }, trueFalse: { look: 'boxes' },
    blank: { look: 'line' }, area: { kind: 'lines' }, arithmetic: { division: 'inline' } },
  it: { number: { shape: 'rounded' }, options: { marker: 'box' }, trueFalse: { look: 'boxes' },
    blank: { look: 'dots' }, area: { kind: 'lines' }, arithmetic: { division: 'potence' } },
  pt: { number: bare, options: { marker: 'none' }, trueFalse: { look: 'bracket' },
    blank: { look: 'line' }, area: { kind: 'lines' }, arithmetic: { division: 'potence' } },
  en: { number: bare, options: { marker: 'none' }, trueFalse: { look: 'boxes' },
    blank: { look: 'line' }, area: { kind: 'lines' }, arithmetic: { division: 'bracket' } },
  // 一、二、 sections; （　） after the stem and A. B. C. in a row; √ × in a bracket; 田字格.
  zh: { number: { shape: 'none', format: 'simp-chinese-informal', suffix: '、' },
    options: { labels: 'alpha-upper', suffix: '.', layout: 'row', bracket: true },
    trueFalse: { look: 'bracket' }, blank: { look: 'line' },
    area: { kind: 'tianzige', spacing: mm(13), lines: 1 }, arithmetic: { division: 'bracket' } },
  // ア イ ウ in a row with （　）, ○ × in a bracket, the number in a square.
  ja: { number: square, options: { labels: 'katakana', suffix: '', layout: 'row', bracket: true },
    trueFalse: { look: 'bracket' }, blank: { look: 'line' }, area: { kind: 'lines' },
    arithmetic: { division: 'bracket' } },
  ar: { number: disc, options: { marker: 'none', prefix: '(', suffix: ')' },
    trueFalse: { look: 'boxes' },
    blank: { look: 'dots' }, area: { kind: 'lines' }, arithmetic: { division: 'bracket' } },
};
TRADITIONS.ca = TRADITIONS.es; // Catalan schools set exercises as Spanish ones do
```

Every edition has the same Markdown: seven `:::exercise` fences whose answers are in the text (`- [x]`, `[[vapour]]`, `- Evaporation -> Water turns into vapour`, `- 864 ÷ 4`). What a country's books do differently is form, so it lives in this table and nowhere else: the number's shape and numerals, the option labels and whether the pupil ticks a box or rings a letter, the true/false look, the blank's look, the writing area and the layout of long division. Catalan takes the Spanish row as it is.

### 2 · Lay the tradition over the house style

```js
// script.js, lines 73–87
const T = TRADITIONS[LANG];
const ficha = {
  id: 'ficha', ...T,
  number: { background: col('accent'), color: T.number.shape === 'none' ? col('accent')
    : col('paper'), fontFamily: LABEL, fontWeight: 700, ...T.number },
  // Chinese and Japanese sheets set the instructions in the gothic (黑体, ゴシック).
  instruction: { bold: true, color: col('ink'), ...(LANG === 'zh' || LANG === 'ja'
    ? { fontFamily: LABEL } : {}) },
  blank: { color: col('ink'), weight: pt(0.7), ...T.blank },
  match: { look: 'dots', gap: em(5), color: col('accent') },
  bank: { order: 'alpha' },
  area: { color: col('rule'), spacing: mm(9), weight: pt(0.6), ...T.area },
  grid: { cell: mm(8.5), fontFamily: TEXT, rule: col('rule'), color: col('ink') },
  marginTop: mm(7), marginBottom: mm(1), itemSpacing: em(0.4),
};
```

One exercise style, `ficha`, carries what all ten sheets share (the blue of the numbers, the grey rules, the room between exercises), and the edition's row is spread over it. What the row leaves out comes from the language: T F, V F, R F, √ ×, ○ × and صح خطأ are the engine's own words, as are a) b) c), A. B. C., ア イ ウ and أ ب ج, so no edition writes them.

### 3 · Give each script its faces

```js
// script.js, lines 27–32
const FACES = {
  zh: { text: 'Noto Serif SC', label: 'Noto Sans SC' },
  ja: { text: 'Klee One', label: 'Noto Sans JP' },
  ar: { text: 'Noto Naskh Arabic', label: 'Baloo Bhaijaan 2' },
}[LANG] ?? { text: 'Nunito', label: 'Baloo 2' };
const [TEXT, LABEL] = [FACES.text, FACES.label];
```

The Latin editions share Nunito and Baloo 2. The Chinese sheet sets its text in Song and its instructions in Hei; the Japanese one sets the text in Klee One, a textbook face, and the instructions in a gothic; the Arabic one uses Noto Naskh Arabic. Klee One's heaviest cut is 600, so the Japanese edition sets its bold at 600 (`boldFontWeight`): a 700 would be drawn by the browser and fail the capture.

### 4 · Head the sheet with lines for a name

```js
// script.js, lines 91–110
const at = (to, edge, x = 0, y = 0, size) => ({ anchor: { to, edge },
  offset: { x: mm(x), y: mm(y) }, ...(size && { size }) });
const field = (id, attr, x, width) => [
  { kind: 'text', id, content: `{attr.${attr}}`, fontFamily: LABEL, fontSize: pt(10),
    fontWeight: 700, color: col('muted'), align: 'left', placement: at('container', 'top-left',
      x, 28) },
  { kind: 'rule', id: `${id}-line`, direction: 'horizontal', thickness: pt(0.75),
    color: col('rule'), placement: at('container', 'top-left', x + 16, 33, { width: mm(width) }) },
];
const head = { enabled: true, minHeight: mm(38), slot: { elements: [
  { kind: 'box', id: 'band', style: { backgroundColor: col('accent'), borderRadius: mm(3) },
    placement: at('container', 'top-left', 0, 0, { width: 'fill', height: mm(21) }) },
  { kind: 'text', id: 'kicker', content: '{title} · {subtitle}', fontFamily: LABEL,
    fontSize: pt(8.5), fontWeight: 700, color: col('tint'), align: 'left',
    placement: at('container', 'top-left', 6, 3.5) },
  { kind: 'text', id: 'title', content: '{titleText}', fontFamily: LABEL, fontSize: pt(22),
    fontWeight: 700, color: col('paper'), align: 'left', lineHeight: 1.1,
    placement: at('container', 'top-left', 6, 9.5) },
  ...field('name', 'nombre', 0, 96), ...field('date', 'fecha', 120, 40),
] } };
```

The level-1 heading draws the band, the course from the frontmatter and the title, and two ruled fields whose words come from the heading's attributes (`nombre="Name" fecha="Date"`), so the German sheet says *Datum* and the Japanese one 名前 without a string in the code.

## The whole recipe

One file, composed from the recipe's folder with the sample text and the Cookbook's shared kit inlined; it builds its own page. To run it, put it in a `<script type="module">` on an empty page, or paste it into the JS panel of a new CodePen (as a module). It imports postext from esm.sh, so there is nothing to install or build.

- Source folder: https://github.com/drnachio/postext/tree/main/cookbook/school-traditions-worksheet

### script.js

```js
// ═══ Postext Cookbook · Nº 169 · One worksheet in ten school traditions ═════════
// https://postext.dev/en/cookbook/school-traditions-worksheet
// Code: MIT · Text: original (CC BY 4.0) · Pictures: none
// Fonts: Nunito, Baloo 2, Klee One, Noto Naskh Arabic and others (SIL OFL) · Needs postext ≥ 1.59.0
import {
  buildDocument, withLoadedFonts, renderPageToCanvas,
} from 'https://esm.sh/postext';
import { renderToPdf, decompressWoff2 } from 'https://esm.sh/postext-pdf';

const LANG = 'en'; // @lang: the language of the worksheet (en es ca fr de it pt zh ja ar)
const RECIPE = 'school-traditions-worksheet';

// ─── 1 · Design ─────────────────────────────────────────────────────────────
// #region palette: a blue-black ink, one blue accent, a pale tint, grey rules
const palette = {
  ink: '#1d2633', accent: '#2a5d9f', tint: '#e8f0fa', rule: '#a9b6c6', muted: '#5d6878',
  paper: '#ffffff',
};
const col = (id) => ({ hex: palette[id], model: 'hex', paletteId: id });
const colorPalette = [
  ...Object.entries(palette).map(([id, hex]) => ({ id, name: id, value: { hex, model: 'hex' } })),
  { id: 'main-color', name: 'accent (defaults)', value: { hex: palette.accent, model: 'hex' } },
];
// #endregion

// #region faces: Latin editions share two faces; Chinese, Japanese and Arabic their own
const FACES = {
  zh: { text: 'Noto Serif SC', label: 'Noto Sans SC' },
  ja: { text: 'Klee One', label: 'Noto Sans JP' },
  ar: { text: 'Noto Naskh Arabic', label: 'Baloo Bhaijaan 2' },
}[LANG] ?? { text: 'Nunito', label: 'Baloo 2' };
const [TEXT, LABEL] = [FACES.text, FACES.label];
// #endregion

// #region answer: the form of the exercises, as each country's school books set them
// The Markdown of every edition has the same seven exercises. What changes is this table:
// how the number prints, how options are labelled and answered, how true/false reads, where
// a blank is written, the paper of the open answer and the layout of long division.
const disc = { shape: 'disc' };
const square = { shape: 'square' };
const bare = { shape: 'none', suffix: '.' };
const TRADITIONS = {
  es: { number: disc, options: { marker: 'none' }, trueFalse: { look: 'boxes' },
    blank: { look: 'line' }, area: { kind: 'lines' }, arithmetic: { division: 'potence' } },
  fr: { number: square, options: { marker: 'box' }, trueFalse: { look: 'boxes' },
    blank: { look: 'dots' }, area: { kind: 'seyes', spacing: mm(8) },
    arithmetic: { division: 'potence' } },
  de: { number: square, options: { marker: 'box' }, trueFalse: { look: 'boxes' },
    blank: { look: 'line' }, area: { kind: 'lines' }, arithmetic: { division: 'inline' } },
  it: { number: { shape: 'rounded' }, options: { marker: 'box' }, trueFalse: { look: 'boxes' },
    blank: { look: 'dots' }, area: { kind: 'lines' }, arithmetic: { division: 'potence' } },
  pt: { number: bare, options: { marker: 'none' }, trueFalse: { look: 'bracket' },
    blank: { look: 'line' }, area: { kind: 'lines' }, arithmetic: { division: 'potence' } },
  en: { number: bare, options: { marker: 'none' }, trueFalse: { look: 'boxes' },
    blank: { look: 'line' }, area: { kind: 'lines' }, arithmetic: { division: 'bracket' } },
  // 一、二、 sections; （　） after the stem and A. B. C. in a row; √ × in a bracket; 田字格.
  zh: { number: { shape: 'none', format: 'simp-chinese-informal', suffix: '、' },
    options: { labels: 'alpha-upper', suffix: '.', layout: 'row', bracket: true },
    trueFalse: { look: 'bracket' }, blank: { look: 'line' },
    area: { kind: 'tianzige', spacing: mm(13), lines: 1 }, arithmetic: { division: 'bracket' } },
  // ア イ ウ in a row with （　）, ○ × in a bracket, the number in a square.
  ja: { number: square, options: { labels: 'katakana', suffix: '', layout: 'row', bracket: true },
    trueFalse: { look: 'bracket' }, blank: { look: 'line' }, area: { kind: 'lines' },
    arithmetic: { division: 'bracket' } },
  ar: { number: disc, options: { marker: 'none', prefix: '(', suffix: ')' },
    trueFalse: { look: 'boxes' },
    blank: { look: 'dots' }, area: { kind: 'lines' }, arithmetic: { division: 'bracket' } },
};
TRADITIONS.ca = TRADITIONS.es; // Catalan schools set exercises as Spanish ones do
// #endregion

// #region style: the one exercise style, the edition's tradition over the house look
const T = TRADITIONS[LANG];
const ficha = {
  id: 'ficha', ...T,
  number: { background: col('accent'), color: T.number.shape === 'none' ? col('accent')
    : col('paper'), fontFamily: LABEL, fontWeight: 700, ...T.number },
  // Chinese and Japanese sheets set the instructions in the gothic (黑体, ゴシック).
  instruction: { bold: true, color: col('ink'), ...(LANG === 'zh' || LANG === 'ja'
    ? { fontFamily: LABEL } : {}) },
  blank: { color: col('ink'), weight: pt(0.7), ...T.blank },
  match: { look: 'dots', gap: em(5), color: col('accent') },
  bank: { order: 'alpha' },
  area: { color: col('rule'), spacing: mm(9), weight: pt(0.6), ...T.area },
  grid: { cell: mm(8.5), fontFamily: TEXT, rule: col('rule'), color: col('ink') },
  marginTop: mm(7), marginBottom: mm(1), itemSpacing: em(0.4),
};
// #endregion

// #region head: the worksheet's head, its title on a tinted band and the lines for a name
const at = (to, edge, x = 0, y = 0, size) => ({ anchor: { to, edge },
  offset: { x: mm(x), y: mm(y) }, ...(size && { size }) });
const field = (id, attr, x, width) => [
  { kind: 'text', id, content: `{attr.${attr}}`, fontFamily: LABEL, fontSize: pt(10),
    fontWeight: 700, color: col('muted'), align: 'left', placement: at('container', 'top-left',
      x, 28) },
  { kind: 'rule', id: `${id}-line`, direction: 'horizontal', thickness: pt(0.75),
    color: col('rule'), placement: at('container', 'top-left', x + 16, 33, { width: mm(width) }) },
];
const head = { enabled: true, minHeight: mm(38), slot: { elements: [
  { kind: 'box', id: 'band', style: { backgroundColor: col('accent'), borderRadius: mm(3) },
    placement: at('container', 'top-left', 0, 0, { width: 'fill', height: mm(21) }) },
  { kind: 'text', id: 'kicker', content: '{title} · {subtitle}', fontFamily: LABEL,
    fontSize: pt(8.5), fontWeight: 700, color: col('tint'), align: 'left',
    placement: at('container', 'top-left', 6, 3.5) },
  { kind: 'text', id: 'title', content: '{titleText}', fontFamily: LABEL, fontSize: pt(22),
    fontWeight: 700, color: col('paper'), align: 'left', lineHeight: 1.1,
    placement: at('container', 'top-left', 6, 9.5) },
  ...field('name', 'nombre', 0, 96), ...field('date', 'fecha', 120, 40),
] } };
// #endregion

const config = {
  locale: t({ en: 'en-gb', es: 'es', ca: 'ca', fr: 'fr', de: 'de', it: 'it', pt: 'pt-BR',
    zh: 'zh-Hans', ja: 'ja', ar: 'ar' }),
  colorPalette,
  page: { sizePreset: 'custom', width: mm(210), height: mm(297), dpi: 150,
    margins: { top: mm(18), bottom: mm(20), left: mm(18), right: mm(18), mirror: true } },
  layout: { layoutType: 'single' },
  bodyText: {
    fontFamily: TEXT, fontSize: pt(LANG === 'ar' ? 13.5 : 12), lineHeight: pt(LANG === 'ar'
      ? 22 : 18), color: col('ink'), boldColor: col('ink'), italicColor: col('ink'),
    referenceColor: col('ink'), textAlign: 'left', firstLineIndent: pt(0),
    boldFontWeight: LANG === 'ja' ? 600 : 700, // Klee One's heaviest cut is 600
    paragraphSpacing: false, hyphenation: { enabled: false }, optimalLineBreaking: true,
    avoidWidows: true, avoidOrphans: true, avoidRunts: true,
  },
  headings: { fontFamily: LABEL, color: col('ink'), fontWeight: 700, levels: [
    { level: 1, fontSize: pt(20), breakBefore: { parity: 'any' }, marginTop: pt(0),
      marginBottom: mm(1), advancedDesign: head },
  ] },
  exerciseStyles: [ficha],
  orderedLists: { fontFamily: LABEL, color: col('accent'), fontWeight: 700, marginTop: pt(0),
    marginBottom: pt(0) },
  paragraphStyles: [{ id: 'colophon', fontFamily: TEXT, fontSize: pt(7.5), lineHeight: pt(10),
    color: col('muted'), firstLineIndent: pt(0), marginTop: mm(6) }],
  header: { elements: [] },
  footer: { elements: [{ kind: 'text', id: 'folio', content: '{pageNumber}', fontFamily: LABEL,
    fontSize: pt(9), fontWeight: 700, color: col('accent'), align: 'center',
    placement: at('page', 'bottom', 0, -11) }] },
};

// ─── 2 · Content ────────────────────────────────────────────────────────────
const markdown = String.raw`---
title: "Science and Maths · Year 4"
subtitle: "Worksheet 7"
---

# Water on the move {nombre="Name" fecha="Date"}

The water on Earth is always moving. The Sun warms the sea, the water rises into the sky and comes back down as rain or snow. This round trip is called the water cycle.

:::exercise
Circle the correct answer.

1. Water that falls from the clouds is called
   - [ ] steam
   - [x] rain
   - [ ] fog
2. When the Sun warms the sea, the water
   - [x] evaporates
   - [ ] freezes
   - [ ] sinks
:::

:::exercise{type="truefalse"}
Tick true or false.

- [x] Clouds are made of tiny drops of water.
- [ ] Ice melts when it gets colder.
- [x] Rivers carry water back to the sea.
- [ ] Rain is salty because it comes from the sea.
:::

:::exercise{bank}
Fill in the gaps with words from the box.

::bank[ice | wind]

The Sun warms the [[sea]]. The water turns into [[vapour]] and rises. High in the sky it cools down and forms [[clouds]]. Then it falls as [[rain]] or snow.
:::

:::exercise
Join each word to what it means.

- Evaporation -> Water turns into vapour
- Condensation -> Vapour turns into drops
- Precipitation -> Water falls from the clouds
- Infiltration -> Water soaks into the ground
:::

:::exercise
Circle the right word.

1. Snow is water in [[liquid | (solid)]] form.
2. Puddles dry up faster on [[(sunny) | cloudy]] days.
3. Most of the water on Earth is [[fresh | (salt)]] water.
:::

:::exercise{type="arithmetic"}
The school's water tank holds 864 litres. Four classes share it equally. How many litres does each class get? Work it out, then check your answer.

- 864 ÷ 4
- 216 × 4
:::

:::exercise{type="open" lines="5"}
Why should we save water? Write two reasons.

:::solution
Fresh water is scarce, and cleaning it and bringing it to our homes takes energy.
:::
:::

:::paragraphs{style="colophon"}
Set in Nunito and Baloo 2 (SIL OFL) · Original text (CC BY 4.0)
:::
`; // content.<lang>.md, inlined by the Cookbook

// ─── 3 · Fonts ──────────────────────────────────────────────────────────────
const FONTS = {
  Nunito: ['400', '700'], 'Baloo 2': ['700'], // the Latin editions
  'Noto Serif SC': ['400', '700'], 'Noto Sans SC': ['700'], // 宋 for the text, 黑 for heads
  'Klee One': ['400', '600'], 'Noto Sans JP': ['600', '700'], // 教科書体 and a gothic
  'Noto Naskh Arabic': ['400', '700'], 'Baloo Bhaijaan 2': ['700'],
};

// ─── 4 · Build & show ───────────────────────────────────────────────────────
// The edition loads its own faces only.
for (const family of Object.keys(FONTS)) if (![TEXT, LABEL].includes(family)) delete FONTS[family];
await loadFonts(FONTS, markdown);
await loadCjkFonts(FONTS, markdown);
await loadArabicFonts(FONTS, markdown);
const doc = await withLoadedFonts(() => buildDocument({ markdown }, config),
  { ...kitFonts(FONTS), text: markdown });
showBook(doc, { title: t({ en: 'Worksheet', es: 'Ficha', ca: 'Fitxa', fr: 'Fiche',
  de: 'Arbeitsblatt', it: 'Scheda', pt: 'Ficha', zh: '练习单', ja: 'プリント', ar: 'ورقة عمل' }) });
offerPdf(() => renderToPdf(doc, { fontProvider: { zh: cjkPdfProvider, ja: cjkPdfProvider,
  ar: arabicPdfProvider }[LANG] ?? fontsourceProvider }), `${RECIPE}-${LANG}.pdf`);

// ─── Kit ── helpers shared by every Cookbook recipe · postext.dev/cookbook ─────

// ─── Kit · core v1 ── the same in every recipe · postext.dev/cookbook
function mm(value) { return { value, unit: 'mm' }; }
function pt(value) { return { value, unit: 'pt' }; }
function em(value) { return { value, unit: 'em' }; }
/** The sample language's string: t({ en: 'Figure', es: 'Figura' }). */
function t(strings) { return strings[LANG] ?? Object.values(strings)[0]; }
/** A file in this recipe's assets folder, served from the Postext repo by jsDelivr. */
function asset(file) { return `https://cdn.jsdelivr.net/gh/drnachio/postext@main/cookbook/${RECIPE}/assets/${file}`; }

// ─── Kit · fonts v3 ── the same in every recipe · postext.dev/cookbook
// Postext loads the faces a config asks for before layout and asks the kit
// for Fontsource's files, the ones the PDF embeds too.

/** buildDocumentWithFonts' options: the resolver, and FONTS' faces loaded
 *  with the config's. FONTS = { 'Family Name': ['400', '400i', '700'] }. */
function kitFonts(FONTS = {}) {
  const faces = Object.entries(FONTS).flatMap(([family, specs]) => specs.map((spec) =>
    ({ family, weight: parseInt(spec, 10), style: spec.endsWith('i') ? 'italic' : 'normal' })));
  return { resolve: fontsourceResolver, faces };
}

/** A face's files with their ranges: latin, then latin-ext and greek when
 *  `text` needs them (kitSubsetsFor). Null for a face Fontsource lacks. */
async function fontsourceResolver(family, weight, style, { text = '' } = {}) {
  const id = fontsourceId(family);
  const meta = await fontsourceMeta(family);
  if (meta && !(await fontsourceWeights(family, style)).includes(weight)) return null;
  kitStatus('Loading fonts…');
  const at = await fontsourceAt(id);
  return ['latin', ...kitSubsetsFor(text, meta)].map((subset) => ({
    source: `${at}files/${id}-${subset}-${weight}-${style}.woff2`,
    unicodeRange: kitRanges()[subset],
  }));
}

/** Each file's unicode-range (a function: the kit runs after the pen's code). */
function kitRanges() {
  return {
    latin: 'U+0000-00FF,U+0131,U+0152-0153,U+02BB-02BC,U+02C6,U+02DA,U+02DC,U+0304,U+0308,U+0329,'
      + 'U+2000-206F,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD',
    'latin-ext': 'U+0100-02BA,U+02BD-02C5,U+02C7-02CC,U+02CE-02D7,U+02DD-02FF,U+0304,U+0308,U+0329,'
      + 'U+1D00-1DBF,U+1E00-1E9F,U+1EF2-1EFF,U+2020,U+20A0-20AB,U+20AD-20C0,U+2113,U+2C60-2C7F,U+A720-A7FF',
    greek: 'U+0370-03FF',
  };
}

/** For the cjk, arabic and comics blocks: loads `faces` (as FONTS) for the
 *  sample `text`; `optional` skips a face Fontsource lacks. Files are added in
 *  the order asked, the last winning a shared character. Resolves to the count. */
async function loadFonts(faces, text = '', { optional = false } = {}) {
  kitStatus('Loading fonts…');
  const ranges = kitRanges();
  const jobs = [];
  for (const [family, specs] of Object.entries(faces)) {
    const id = fontsourceId(family);
    const todo = [...new Set(specs)].map((spec) => [parseInt(spec, 10), spec.endsWith('i') ? 'italic' : 'normal'])
      .filter(([weight, style]) => !hasFace(family, weight, style)); // before any await
    const at = fontsourceAt(id);
    const meta = optional || /[^\0-ÿ]/u.test(text) ? await fontsourceMeta(family) : null;
    const subsets = ['latin', ...kitSubsetsFor(text, meta)];
    for (const [weight, style] of todo) {
      if (optional && !(meta && (await fontsourceWeights(family, style)).includes(weight))) continue;
      for (const subset of subsets) {
        const url = `${await at}files/${id}-${subset}-${weight}-${style}.woff2`;
        const face = new FontFace(family, `url(${url}) format('woff2')`,
          { weight: String(weight), style, unicodeRange: ranges[subset] });
        jobs.push(face.load().catch(() => {
          if (subset === 'latin' && !optional) throw new Error(`Fontsource has no ${family} ${weight} ${style}`);
        }));
      }
    }
  }
  const ready = await Promise.all(jobs).catch((error) => { kitFail(error); throw error; });
  return ready.filter((face) => face && document.fonts.add(face)).length;
}

/** A loaded FontFace covers this face (fonts.check() says yes to any family). */
function hasFace(family, weight, style) {
  for (const face of document.fonts) {
    if (face.status !== 'loaded' || face.style !== style) continue;
    if (face.family.replace(/^["']|["']$/g, '') !== family) continue;
    const [low, high = low] = face.weight.split(' ').map(Number);
    if (weight >= low && weight <= high) return true;
  }
  return false;
}

/** The files beyond latin `text` needs that `meta`'s family ships. */
function kitSubsetsFor(text, meta) {
  return [[/[Ā-˿ᴀ-ᶿḀ-ỿ†ℓⱠ-Ɀ꜠-ꟿ]/u, 'latin-ext'], [/[Ͱ-Ͽ]/u, 'greek']]
    .filter(([re, x]) => re.test(text) && meta?.subsets?.includes(x)).map(([, x]) => x);
}

/** Fontsource's id for a family: 'Source Serif 4' → 'source-serif-4'. */
function fontsourceId(family) { return family.toLowerCase().replace(/\s+/g, '-'); }

/** A package's folder at the one version @5 names now (#766). */
function fontsourceAt(id, u = `https://cdn.jsdelivr.net/npm/@fontsource/${id}@`) {
  return (fontsourceAt.c ??= {})[id] ??= fetch(u + '5/package.json').then((r) => r.json())
    .then((p) => p.version || 5, () => 5).then((v) => `${u}${v}/`);
}

/** The family's Fontsource metadata (weights, styles, subsets), or null. */
function fontsourceMeta(family, id = fontsourceId(family)) {
  return (fontsourceMeta.c ??= {})[id] ??= fetch(`https://api.fontsource.org/v1/fonts/${id}`)
    .then((res) => (res.ok ? res.json() : null), () => null);
}

/** The weights the package ships in `style`: the API pairs none (no Libre
 *  Caslon 700 italic file), so italics are read from latin-italic.css. */
function fontsourceWeights(family, style, id = fontsourceId(family)) {
  return (fontsourceWeights.c ??= {})[id + style] ??= fontsourceMeta(family).then(async (m) => {
    if (!m?.styles.includes(style)) return m ? [] : [400, 700];
    const css = style === 'italic' ? await fetch(`${await fontsourceAt(id)}latin-italic.css`).then((r) => (r.ok ? r.text() : ''), () => '') : '';
    const w = [...css.matchAll(/weight: (\d+)/g)].map((x) => +x[1]);
    return w.length ? w : m.weights;
  });
}

// ─── Kit · viewer v2 ── the same in every recipe · postext.dev/cookbook
/** The pages as spreads on a dark desk, page 1 alone, then verso | recto,
 *  each painted when it scrolls near. Other options go to renderPageToCanvas. */
function showPages(docs, { title, width = 460, ...render } = {}) {
  const root = viewer(title);
  const pages = [docs].flat().flatMap((doc) =>
    doc.pages.map((page) => ({ doc, page, n: (doc.pageIndexOffset ?? 0) + page.index })));
  const spreads = [];
  let verso = null;
  for (const p of pages) {
    if (p.n % 2 === 1) { if (verso) spreads.push([verso, null]); verso = p; }
    else { spreads.push([verso, p]); verso = null; }
  }
  if (verso) spreads.push([verso, null]);
  const density = Math.min(window.devicePixelRatio || 1, 2);
  showPages.painter?.disconnect();
  const painter = new IntersectionObserver((entries) => {
    for (const { isIntersecting, target } of entries) {
      if (!isIntersecting) continue;
      painter.unobserve(target);
      const { doc, page } = target.postext;
      renderPageToCanvas(page, doc, target, { ...render, scale: (width * density) / page.width });
    }
  }, { rootMargin: '800px' });
  showPages.painter = painter;
  root.replaceChildren(...spreads.map((pair) => {
    const spread = document.createElement('div');
    spread.className = 'pt-spread';
    for (const p of pair) {
      const figure = document.createElement('figure');
      if (p) {
        const label = p.page.pageLabel || String(p.n + 1);
        const canvas = document.createElement('canvas');
        canvas.postext = p;
        canvas.style.aspectRatio = `${p.page.width} / ${p.page.height}`;
        canvas.setAttribute('role', 'img');
        canvas.setAttribute('aria-label', `Page ${label}`);
        const folio = document.createElement('figcaption');
        folio.textContent = label;
        figure.append(canvas, folio);
        painter.observe(canvas);
      } else figure.className = 'pt-blank';
      spread.append(figure);
    }
    return spread;
  }));
  kitStatus(`${pages.length} ${pages.length === 1 ? 'page' : 'pages'}`);
  document.documentElement.dataset.postext = 'ready';
  return pages.length;
}

/** The desk, the bar and the error reporting, created once. */
function viewer(title) {
  if (!document.getElementById('pt-kit')) {
    document.head.insertAdjacentHTML('beforeend', `<style id="pt-kit">
      :root { color-scheme: dark; }
      body { margin: 0; background: #0e1014; color: #b9bcc4; font: 13px/1.45 system-ui, sans-serif; }
      #pt-bar { position: sticky; top: 0; z-index: 1; display: flex; flex-wrap: wrap; align-items: center;
        gap: 6px 16px; padding: 10px 16px; background: rgb(14 16 20 / .92); backdrop-filter: blur(6px);
        border-bottom: 1px solid #23262d; }
      #pt-bar strong { color: #f4f1ea; font-weight: 600; }
      #pt-actions { display: flex; gap: 12px; margin-left: auto; }
      #pt-actions a, #pt-actions button { color: #d8a21a; font: inherit; background: none; border: 0; padding: 0; cursor: pointer; }
      #pages { display: grid; justify-items: center; gap: 48px; padding: 32px 16px 72px; }
      .pt-spread { display: flex; }
      .pt-spread figure { margin: 0; width: min(460px, 44vw); }
      .pt-spread canvas { display: block; width: 100%; background: #fff;
        box-shadow: 0 1px 2px rgb(0 0 0 / .5), 0 22px 44px -16px rgb(0 0 0 / .8); }
      .pt-spread figure:first-child canvas { box-shadow: inset -14px 0 14px -14px rgb(0 0 0 / .18), 0 1px 2px rgb(0 0 0 / .5), 0 22px 44px -16px rgb(0 0 0 / .8); }
      .pt-spread figcaption { margin-top: 10px; text-align: center; font: 600 10px/1 system-ui, sans-serif;
        letter-spacing: .18em; text-transform: uppercase; color: #6c7079; }
      .pt-blank { visibility: hidden; }
      @media (max-width: 760px) {
        .pt-spread { flex-direction: column; gap: 32px; }
        .pt-spread figure { width: min(460px, 92vw); }
        .pt-blank { display: none; }
      }
    </style>`);
    document.body.insertAdjacentHTML('afterbegin',
      '<header id="pt-bar"><strong id="pt-title"></strong><span id="pt-status" role="status"></span><span id="pt-actions"></span></header>');
    document.getElementById('pt-title').textContent = document.title || 'Postext';
    addEventListener('error', (event) => kitFail(event.error ?? event.message));
    addEventListener('unhandledrejection', (event) => kitFail(event.reason));
  }
  if (title) document.getElementById('pt-title').textContent = title;
  return document.getElementById('pages')
    ?? document.body.appendChild(Object.assign(document.createElement('main'), { id: 'pages' }));
}

function kitStatus(text) {
  viewer();
  document.getElementById('pt-status').textContent = text;
}

function kitFail(error) {
  document.documentElement.dataset.postext = 'error';
  kitStatus(`Error: ${error?.message ?? error}`);
}

// ─── Kit · pdf v3 ── the same in every recipe that exports a PDF
/** The Fontsource files the screen used, as TrueType, with their range and
 *  place: the nearest weight the family ships in that style, upright with no italic;
 *  latin, then what its letters need (kitSubsetsFor). */
async function fontsourceProvider(family, weight, style, request) {
  const id = fontsourceId(family);
  const meta = await fontsourceMeta(family);
  const s = style === 'italic' && meta && !meta.styles.includes('italic') ? 'normal' : style;
  const shipped = meta ? await fontsourceWeights(family, s) : [];
  const weights = shipped.length ? shipped : [400, 700];
  const w = weights.reduce((a, b) => (Math.abs(b - weight) < Math.abs(a - weight) ? b : a));
  const text = String.fromCodePoint(...(request?.codePoints ?? []));
  const files = await Promise.all(['latin', ...kitSubsetsFor(text, meta)].map(async (subset, order) => {
    const res = await fetch(`${await fontsourceAt(id)}files/${id}-${subset}-${w}-${s}.woff2`);
    if (!res.ok) throw new Error(`Fontsource has no ${family} ${w} ${s} ${subset}`);
    return Object.assign(await decompressWoff2(new Uint8Array(await res.arrayBuffer())),
      { unicodeRange: kitRanges()[subset], order });
  }));
  return files.length === 1 ? files[0] : files;
}

/** A "Build the PDF" button; then "Open the PDF" (a new tab: CodePen's frame
 *  shows no PDFs) and a download link. */
function offerPdf(makePdf, filename) {
  viewer();
  const button = Object.assign(document.createElement('button'), { type: 'button', textContent: 'Build the PDF' });
  button.dataset.postextPdf = filename;
  button.addEventListener('click', async () => {
    button.disabled = true;
    button.textContent = 'Building the PDF…';
    try {
      const bytes = await makePdf();
      const url = URL.createObjectURL(new Blob([bytes], { type: 'application/pdf' }));
      const size = `${Math.max(1, Math.round(bytes.length / 1024))} KB`;
      button.replaceWith(
        Object.assign(document.createElement('a'), { href: url, target: '_blank', rel: 'noopener', textContent: 'Open the PDF ↗' }),
        Object.assign(document.createElement('a'), { href: url, download: filename, textContent: `Download ${filename} · ${size}` }));
    } catch (error) {
      button.disabled = false;
      button.textContent = 'Build the PDF';
      kitFail(error);
    }
  });
  document.getElementById('pt-actions').append(button);
}

// ─── Kit · cjk v2 ── Chinese, Japanese and Korean books · postext.dev/cookbook
// Fontsource ships a CJK family as about a hundred files per weight, each
// declared in its stylesheet with the unicode-range it covers. The screen
// loads the files the sample touches; the PDF gets the same files for the
// characters its pages set in each face, and embeds each as a subset.
// A book bound on the right (vertical text) is shown with its spreads
// mirrored: page 1 alone on the left of the spine, then [3 | 2].

/** The files of a Fontsource face, read from its stylesheet: { url, range,
 *  ranges }, the last declared first (the order the browser tries them in). */
function cjkSlices(family, weight, style) {
  cjkSlices.cache ??= new Map();
  const id = fontsourceId(family);
  const css = `${id}/${weight}${style === 'italic' ? '-italic' : ''}.css`;
  if (!cjkSlices.cache.has(css)) {
    let at;
    cjkSlices.cache.set(css, fontsourceAt(id).then((a) => fetch(at = a + css.slice(id.length + 1)))
      .then((res) => {
        if (!res.ok) throw new Error(`Fontsource has no ${family} ${weight} ${style} (${res.status})`);
        return res.text();
      })
      .then((text) => [...text.matchAll(/@font-face\s*{([^}]*)}/g)].map(([, rule]) => {
        const range = /unicode-range:\s*([^;]+);/.exec(rule)?.[1].trim() ?? 'U+0-10FFFF';
        const ranges = range.split(',').map((part) => {
          const [lo, hi = lo] = part.trim().slice(2).split('-');
          return [parseInt(lo, 16), parseInt(hi, 16)];
        });
        return { url: new URL(/url\(([^)]+?\.woff2)\)/.exec(rule)[1], at).href, range, ranges };
      }).reverse()));
  }
  return cjkSlices.cache.get(css);
}

/** The file of `slices` the screen sets code point `cp` in, if any: the
 *  last one loadCjkFonts adds whose range holds it. A numbered file that
 *  repeats a letter of latin is added after latin, and wins it. */
function cjkSliceFor(slices, cp) {
  const holds = (slice) => slice.ranges.some(([lo, hi]) => cp >= lo && cp <= hi);
  return slices.reduce((last, slice) => (holds(slice) ? slice : last), undefined);
}

/** Whether Fontsource serves `family` as a Chinese, Japanese or Korean
 *  family (its subsets name the script). Fails when the API does not
 *  answer: a CJK face taken for a Latin one would paint in a system face. */
async function isCjkFamily(family) {
  const meta = await fontsourceMeta(family);
  if (!meta) throw new Error(`api.fontsource.org did not describe ${family}: reload to try again`);
  return !!meta.subsets?.some((subset) => /^(chinese|japanese|korean)/.test(subset));
}

/** faces = { 'Noto Serif TC': ['400', '700'] }, as for loadFonts: the
 *  whole FONTS object may be passed, its other families are left to
 *  loadFonts. Adds one FontFace per file of each CJK face with its
 *  unicodeRange, then loads the files `text` touches. `text` is what the
 *  faces set: the sample for the text face; a book in several voices calls
 *  it once per voice (loadCjkFonts({ 'LXGW WenKai TC': ['400'] }, quotes)),
 *  so the heading and quotation faces fetch and check only their own
 *  characters. Fails when a character of `text` is in no file of a face.
 *  List every weight the pages use: a weight left to the engine's later round
 *  gets the latin file only. With { vertical: true } it also loads each
 *  family's vertical forms (brackets, quotes, pause marks) for the canvas,
 *  which needs loadVerticalAlternates imported from postext. Resolves to
 *  the number of files loaded. */
async function loadCjkFonts(faces, text, { vertical = false } = {}) {
  kitStatus('Loading fonts…');
  let loaded = 0;
  try {
    if (vertical && typeof loadVerticalAlternates !== 'function') {
      throw new Error('loadCjkFonts(…, { vertical: true }) needs loadVerticalAlternates imported from postext');
    }
    for (const [family, specs] of Object.entries(faces)) {
      if (!(await isCjkFamily(family))) continue;
      const twin = [];
      for (const spec of new Set(specs)) {
        const weight = parseInt(spec, 10);
        const style = spec.endsWith('i') ? 'italic' : 'normal';
        const slices = await cjkSlices(family, weight, style);
        const missing = [...new Set(text)].filter((ch) => /\S/.test(ch) && !cjkSliceFor(slices, ch.codePointAt(0)));
        if (missing.length) {
          throw new Error(`${family} ${spec} has no file for ${missing.slice(0, 12).join(' ')}: `
            + `give each face the text it sets (loadCjkFonts({ '${family}': ['${spec}'] }, text))`);
        }
        for (const slice of slices) {
          document.fonts.add(new FontFace(family, `url(${slice.url}) format('woff2')`,
            { weight: String(weight), style, unicodeRange: slice.range }));
          twin.push({ source: slice.url, weight: String(weight), style, unicodeRange: slice.range });
        }
        const font = `${style === 'italic' ? 'italic ' : ''}${weight} 16px "${family}"`;
        loaded += (await document.fonts.load(font, text)).length;
        if (!document.fonts.check(font, text)) throw new Error(`${family} ${spec} did not load for the sample`);
      }
      // The same files under a twin name with the `vert` feature on: the
      // canvas paints the punctuation of vertical lines with it.
      if (vertical && twin.length) await loadVerticalAlternates(family, twin);
    }
  } catch (error) {
    kitFail(error);
    throw error;
  }
  return loaded;
}

/** The PDF font provider for recipes with CJK faces: a family whose
 *  Fontsource subsets are Chinese, Japanese or Korean gets the files the
 *  screen set its pages' characters in (`request.codePoints`), each marked
 *  with its unicode-range and its place in the order loadCjkFonts added
 *  them: postext-pdf sets a character two files hold in the one added
 *  last, as the browser does. Any other family gets the latin file
 *  fontsourceProvider fetches (the "pdf" block) and, when the face sets
 *  letters only latin-ext has, that file too. */
async function cjkPdfProvider(family, weight, style, request) {
  if (!(await isCjkFamily(family))) return cjkLatinPdfFiles(family, weight, style, request);
  const meta = await fontsourceMeta(family);
  const weights = meta.weights?.length ? meta.weights : [400, 700];
  const w = weights.reduce((a, b) => (Math.abs(b - weight) < Math.abs(a - weight) ? b : a));
  const s = style === 'italic' && !meta.styles.includes('italic') ? 'normal' : style;
  const slices = await cjkSlices(family, w, s);
  const picked = new Set();
  for (const cp of request?.codePoints ?? []) {
    const slice = cjkSliceFor(slices, cp);
    if (slice) picked.add(slice);
  }
  if (!picked.size) picked.add(slices[0]);
  return Promise.all(slices.map(async (slice, order) => {
    if (!picked.has(slice)) return null;
    const res = await fetch(slice.url);
    if (!res.ok) throw new Error(`Fontsource file ${slice.url} (${res.status})`);
    const bytes = await decompressWoff2(new Uint8Array(await res.arrayBuffer()));
    return Object.assign(bytes, { unicodeRange: slice.range, order });
  })).then((files) => files.filter(Boolean));
}

/** A Latin family set next to the CJK faces: its latin file, then its
 *  latin-ext file when the face sets letters only latin-ext has (ō ū in
 *  Hepburn rōmaji, ǎ in pinyin), the file loadFonts adds on screen for
 *  them, each marked with its unicode-range and its place in that order:
 *  the PDF sets a character in the file the browser took it from. A face
 *  Fontsource ships without latin-ext, or whose file does not come, gets
 *  latin alone, and the PDF names the letters it lacks. */
async function cjkLatinPdfFiles(family, weight, style, request) {
  const meta = await fontsourceMeta(family);
  const beyond = [...(request?.codePoints ?? [])].some(cjkLatinExtOnly);
  if (!beyond || !meta?.subsets?.includes('latin-ext')) return fontsourceProvider(family, weight, style);
  const weights = meta.weights?.length ? meta.weights : [400, 700];
  const w = weights.reduce((a, b) => (Math.abs(b - weight) < Math.abs(a - weight) ? b : a));
  const s = style === 'italic' && !meta.styles.includes('italic') ? 'normal' : style;
  const id = fontsourceId(family);
  const url = `${await fontsourceAt(id)}files/${id}-latin-ext-${w}-${s}.woff2`;
  const [latin, ext] = await Promise.all([fontsourceProvider(family, weight, style), fetch(url)
    .then(async (res) => (res.ok ? decompressWoff2(new Uint8Array(await res.arrayBuffer())) : null), () => null)]);
  const ranges = kitRanges();
  return ext ? [Object.assign(latin, { unicodeRange: ranges.latin, order: 0 }),
    Object.assign(ext, { unicodeRange: ranges['latin-ext'], order: 1 })] : latin;
}

/** Whether code point `cp` is in Fontsource's latin-ext file and not in
 *  its latin file: Latin Extended-A and -B, IPA, the spacing modifiers and
 *  Latin Extended Additional (loadFonts's test for latin-ext), less the
 *  few latin holds too (ı Œ œ ʻ ʼ ˆ ˚ ˜). */
function cjkLatinExtOnly(cp) {
  if (!((cp >= 0x100 && cp <= 0x2ff) || (cp >= 0x1e00 && cp <= 0x1eff))) return false;
  return ![0x131, 0x152, 0x153, 0x2bb, 0x2bc, 0x2c6, 0x2da, 0x2dc].includes(cp);
}

/** showPages for a book bound on either edge. A right-bound book (the
 *  document says so: doc.binding is 'right' for page.binding 'right' and
 *  for vertical text) lies on the desk as it opens: page 1 alone on the
 *  left of the spine, then [3 | 2], the spine shade on each page's inner
 *  edge. `binding` ('left' | 'right') overrides the document's. */
function showBook(docs, { binding, ...options } = {}) {
  const count = showPages(docs, options);
  const right = (binding ?? [docs].flat()[0]?.binding) === 'right';
  if (!document.getElementById('pt-kit-cjk')) {
    // The pages keep direction ltr: a canvas draws text in the direction its
    // element inherits, and under rtl each run would end where the engine
    // starts it, its brackets mirrored.
    document.head.insertAdjacentHTML('beforeend', `<style id="pt-kit-cjk">
      .pt-spread[dir="rtl"] canvas { direction: ltr; }
      .pt-spread[dir="rtl"] figure:first-child canvas { box-shadow: inset 14px 0 14px -14px rgb(0 0 0 / .18),
        0 1px 2px rgb(0 0 0 / .5), 0 22px 44px -16px rgb(0 0 0 / .8); }
    </style>`);
  }
  // Each pair stays [verso, recto] in the page; right to left, the verso
  // sits on the right. Phones stack the pages in reading order either way.
  for (const spread of document.querySelectorAll('#pages > .pt-spread')) spread.dir = right ? 'rtl' : 'ltr';
  document.getElementById('pages').dataset.binding = right ? 'right' : 'left';
  return count;
}

// ─── Kit · arabic v2 ── Arabic-script faces · postext.dev/cookbook
// Fontsource ships an Arabic family as one file per subset and weight: the
// `arabic` file holds the letters, the harakat, the Arabic-Indic digits, the
// Arabic punctuation and the presentation forms; `latin` and `latin-ext`
// hold the rest. loadFonts loads the latin files; this block adds the arabic
// file of every Arabic family, for the canvas and for the PDF, which shapes
// the letters with HarfBuzz from the same bytes.

/** The code points of Fontsource's `arabic` subset, as its stylesheets
 *  declare them (the same unicode-range the browser picks the file by). A
 *  function, not a const: the kit is inlined after the recipe's top-level
 *  awaits, and a const read before its line throws, where a function
 *  declaration is hoisted. */
function arabicRange() {
  return 'U+0600-06FF,U+0750-077F,U+0870-088E,U+0890-0891,U+0897-08E1,U+08E3-08FF,'
    + 'U+200C-200E,U+2010-2011,U+204F,U+2E41,U+FB50-FDFF,U+FE70-FE74,U+FE76-FEFC,U+102E0-102FB,'
    + 'U+10E60-10E7E,U+10EC2-10EC4,U+10EFC-10EFF,U+1EE00-1EEFF';
}

/** Whether code point `cp` is in the arabic file. */
function inArabicRange(cp) {
  inArabicRange.ranges ??= arabicRange().split(',').map((part) => {
    const [lo, hi = lo] = part.slice(2).split('-');
    return [parseInt(lo, 16), parseInt(hi, 16)];
  });
  return inArabicRange.ranges.some(([lo, hi]) => cp >= lo && cp <= hi);
}

/** Whether Fontsource serves `family` with an `arabic` subset. Fails when
 *  the API does not answer: an Arabic face taken for a Latin one would set
 *  its letters in a system face. */
async function isArabicFamily(family) {
  const meta = await fontsourceMeta(family);
  if (!meta) throw new Error(`api.fontsource.org did not describe ${family}: reload to try again`);
  return !!meta.subsets?.includes('arabic');
}

/** The arabic file of a face. */
async function arabicFileUrl(family, weight, style) {
  const id = fontsourceId(family);
  return `${await fontsourceAt(id)}files/${id}-arabic-${weight}-${style}.woff2`;
}

/** faces = { Amiri: ['400', '700'] }, as for loadFonts, after it: the whole
 *  FONTS object may be passed, its families without an arabic subset are
 *  left alone. Adds the arabic file of every listed weight of each Arabic
 *  family (the latin files come from loadFonts) and loads it. `text` is
 *  the sample: fails when it holds an Arabic-script character the arabic
 *  file does not cover. List every weight the pages set in Arabic: a weight
 *  left to the engine's later round gets the latin file only, and its Arabic letters
 *  fall back to a system face. Resolves to the number of files loaded. */
async function loadArabicFonts(faces, text = '') {
  kitStatus('Loading fonts…');
  let loaded = 0;
  try {
    const outside = [...new Set(text)].filter((ch) => /\p{Script=Arabic}/u.test(ch) && !inArabicRange(ch.codePointAt(0)));
    if (outside.length) throw new Error(`Fontsource's arabic files have no ${outside.slice(0, 12).join(' ')}`);
    for (const [family, specs] of Object.entries(faces)) {
      if (!(await isArabicFamily(family))) continue;
      for (const spec of new Set(specs)) {
        const weight = parseInt(spec, 10);
        const style = spec.endsWith('i') ? 'italic' : 'normal';
        const face = new FontFace(family, `url(${await arabicFileUrl(family, weight, style)}) format('woff2')`,
          { weight: String(weight), style, unicodeRange: arabicRange() });
        document.fonts.add(await face.load().catch(() => {
          throw new Error(`Fontsource has no arabic file for ${family} ${weight} ${style}`);
        }));
        loaded++;
      }
    }
  } catch (error) {
    kitFail(error);
    throw error;
  }
  return loaded;
}

/** The PDF font provider for recipes with Arabic faces: a family with an
 *  arabic subset gets its arabic file when its pages set Arabic letters
 *  (`request.codePoints`), then its latin file, and its latin-ext file for
 *  the letters beyond latin (transliteration: ā ḥ ʿ), each marked with its
 *  unicode-range and its place in the order the screen added them (latin
 *  and latin-ext by loadFonts, then arabic): the arabic file also has a
 *  space and brackets, which the browser takes from latin, the file whose
 *  range holds them, and postext-pdf follows it. Any other family goes to
 *  fontsourceProvider (the "pdf" block). */
async function arabicPdfProvider(family, weight, style, request) {
  if (!(await isArabicFamily(family))) return fontsourceProvider(family, weight, style, request);
  const meta = await fontsourceMeta(family);
  const weights = meta.weights?.length ? meta.weights : [400, 700];
  const w = weights.reduce((a, b) => (Math.abs(b - weight) < Math.abs(a - weight) ? b : a));
  const s = style === 'italic' && !meta.styles.includes('italic') ? 'normal' : style;
  const wanted = [...(request?.codePoints ?? [])];
  const id = fontsourceId(family);
  const subsets = !wanted.length || wanted.some(inArabicRange) ? ['arabic', 'latin'] : ['latin'];
  if (meta.subsets.includes('latin-ext') && wanted.some((cp) => /[Ā-˿Ḁ-ỿ]/u.test(String.fromCodePoint(cp)))) {
    subsets.push('latin-ext');
  }
  const at = await fontsourceAt(id);
  return Promise.all(subsets.map(async (subset) => {
    const url = `${at}files/${id}-${subset}-${w}-${s}.woff2`;
    const res = await fetch(url);
    if (!res.ok) throw new Error(`Fontsource file ${url} (${res.status})`);
    const bytes = await decompressWoff2(new Uint8Array(await res.arrayBuffer()));
    return Object.assign(bytes, { unicodeRange: subset === 'arabic' ? arabicRange() : kitRanges()[subset],
      order: ['latin', 'latin-ext', 'greek', 'arabic'].indexOf(subset) });
  }));
}

// ─── /Kit ───────────────────────────────────────────────────────────────────────
```

## Variations

### Print the teacher's copy

Every answer goes into its slot in magenta: the brackets, the boxes, the blanks and the quotient.

```diff
   exerciseStyles: [ficha],
+  exercises: { edition: 'teacher' },
```

### Collect the answers at the foot of the sheet

`placement: 'after'` sets each exercise's key under it; `'inverted'` turns it upside down, as puzzle pages do.

```diff
+  exercises: { solutions: { placement: 'inverted', layout: 'key' } },
```

## Pitfalls

- A face without a 700 cut makes the bold of the stems' numbers a synthesized one. Give such a text face `boldFontWeight` with a weight it ships.
- The ○ of the Japanese instructions and the √ of the Chinese ones are only in the CJK faces: set them in a sentence of the CJK text, not in a Latin label.

## Credits

- Recipe: Ignacio Ferro ([@drnachio](https://github.com/drnachio))
- Type: Nunito (OFL-1.1), Baloo 2 (OFL-1.1), Noto Serif SC (OFL-1.1), Noto Sans SC (OFL-1.1), Klee One (OFL-1.1), Noto Sans JP (OFL-1.1), Noto Naskh Arabic (OFL-1.1), Baloo Bhaijaan 2 (OFL-1.1)
- Code: MIT · Sample content: CC-BY-4.0

## Related

- [Nº 171 · A Chinese exercise book, pupil's and teacher's](https://postext.dev/en/cookbook/chinese-exercise-book.md): A 练习册 in Chinese and maths: sections 一、二、, （　） brackets, 田字格 and sums in columns, built twice from one text, for the pupil and the teacher. · Level 2 (Intermediate) · Workbooks & exercises, Textbooks
- [Nº 172 · A Japanese drill with the answers upside down](https://postext.dev/en/cookbook/japanese-drill-upside-down-answers.md): Two pages of a Japanese drill series, arithmetic across and kanji in columns, each exercise followed by its answers printed upside down. · Level 2 (Intermediate) · Workbooks & exercises, Textbooks
- [Nº 173 · An Arabic workbook, right to left](https://postext.dev/en/cookbook/arabic-workbook-rtl.md): A primary Arabic workbook unit set right to left: choices with أ ب ج, matching columns, a word bank, صح or خطأ boxes, a word search and Arabic-Indic digits. · Level 2 (Intermediate) · Workbooks & exercises, Textbooks