A puzzle page with the answers upside down

// ═══ Postext Cookbook · Nº 174 · A puzzle page with the answers upside down ═══════
// https://postext.dev/en/cookbook/puzzle-page-upside-down-answers
// Code: MIT · Text: original (CC BY 4.0) · Pictures: generated with diffusion models
// Fonts: Baloo 2, Nunito, Fredoka (SIL OFL 1.1) · Needs postext ≥ 1.59.0
import {
  buildDocumentWithFonts, renderPageToCanvas, registerResourceImage,
} from 'https://esm.sh/postext';
import { renderToPdf, decompressWoff2 } from 'https://esm.sh/postext-pdf';

const LANG = 'en'; // @lang: the language of the sample document ('en' | 'es')
const RECIPE = 'puzzle-page-upside-down-answers';

// ─── 1 · Design ─────────────────────────────────────────────────────────────
// #region palette: reef colours: deep blue ink, coral, sea green, a sandy paper
const palette = {
  ink: '#16324a', // text: a deep sea blue
  coral: '#e8573f', // the accent: puzzle numbers, the title kicker
  sea: '#0f8b8d', // the second: crossword and word-search rules, the riddle's rings
  sun: '#ffc93c', // the turtle card's badge
  card: '#fff4e0', // the puzzle cards
  muted: '#5d7180', // answers, colophon, folio
  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.coral, model: 'hex' } },
];
// #endregion
const [DISPLAY, TEXT, LABEL] = ['Baloo 2', 'Nunito', 'Fredoka'];

// #region answer: every puzzle on a card, its answers turned upside down under it
// placement 'inverted' sets each puzzle's key after it in a box turned 180°, inside the
// puzzle's card, so a page break never parts a puzzle from its answers. The key is made
// from the puzzle: the crossword's words by number, the ringed option, the right order.
const puzzle = {
  id: 'puzzle',
  box: 'card', // the card each puzzle sits on (a calloutStyles id)
  number: { shape: 'disc', fontFamily: DISPLAY, background: col('coral') },
  instruction: { fontFamily: TEXT, bold: false },
  options: { marker: 'circle', labels: 'none' }, // a ring to colour in, no letters
  grid: { fontFamily: LABEL, rule: col('sea'), cell: em(1.45) },
  match: { color: col('sea') },
  area: { kind: 'lines', color: col('sea') },
  answers: { color: col('coral'), fontFamily: LABEL },
  solutions: { placement: 'inverted', box: 'turned' },
  marginTop: mm(0), marginBottom: mm(0),
};