/* GENERATED by scripts/build-css.mjs from assets/css/src/ — edit the sources, not this file. */
@layer tokens, base, legacy, layout, components, pages;

/* 00-tokens.css */
@layer tokens {
/* ==========================================================================
   Tokens — "Nagekeken" (docs/redesign/03-visual-design-system.md)
   Light = schrift (squared exercise book), dark = bord (graphite board).
   Red (--pen) is teacher ink only: marks, focus, the answer circle. Never a
   button fill (white on dark-theme pen = 2.77:1, fails AA).
   ========================================================================== */

:root {
  color-scheme: dark light;

  /* type */
  --font-display: "Bricolage Grotesque", "Bricolage Grotesque Fallback", system-ui, sans-serif;
  --font-body: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-note: Caveat, "Caveat Fallback", "Segoe Print", cursive;
  --font-math: math, "Cambria Math", "STIX Two Math", serif;
  --fs-xs: 0.8125rem;
  --fs-sm: 0.9375rem;
  --fs-base: clamp(1.0625rem, 1rem + 0.25vw, 1.125rem);
  --fs-md: 1.25rem;
  --fs-lg: clamp(1.5rem, 1.3rem + 0.8vw, 1.875rem);
  --fs-xl: clamp(2rem, 1.5rem + 2.4vw, 3.25rem);
  --fs-2xl: clamp(2.5rem, 1.6rem + 4.2vw, 4.75rem);

  /* space (8 px module; notebook square = 24 px) */
  --s-1: 4px; --s-2: 8px; --s-3: 12px; --s-4: 16px; --s-5: 24px;
  --s-6: 32px; --s-7: 48px; --s-8: 72px; --s-9: 96px;
  --square: 24px;

  /* shape */
  --r-1: 4px; --r-2: 8px; --r-pill: 999px;

  /* layout */
  --w-read: 68ch; --w-work: 1200px; --w-wide: 1360px;
  --gutter: clamp(16px, 4vw, 32px);

  /* motion (docs/redesign/06) */
  --ease-out: cubic-bezier(0.23, 1, 0.32, 1);
  --ease-in-out: cubic-bezier(0.77, 0, 0.175, 1);
  --ease-draw: cubic-bezier(0.65, 0, 0.35, 1);
  --t-press: 140ms; --t-ui: 180ms; --t-panel: 240ms; --t-draw: 420ms;
  --stagger: 40ms;

  /* layers */
  --z-header: 20; --z-drop: 30; --z-search: 40; --z-dialog: 50; --z-toast: 60;
}

/* ---------- Dark = bord (default when no data-theme) ---------- */
:root,
:root[data-theme="dark"] {
  color-scheme: dark;
  --paper: #121416;
  --surface: #1A1D21;
  --sunk: #0D0F11;
  --grid: rgba(170, 190, 220, 0.07);
  --margin-rule: rgba(255, 107, 110, 0.35);
  --ink: #F2F1EC;
  --ink-2: #B8BBC1;
  --ink-3: #969AA1;
  --line: rgba(242, 241, 236, 0.12);
  --line-strong: rgba(242, 241, 236, 0.24);
  --pen: #FF6B6E;
  --pen-strong: #FF6B6E;
  --pen-wash: rgba(255, 107, 110, 0.12);
  --ok: #4DD6A0;
  --ok-wash: rgba(77, 214, 160, 0.12);
  --warn: #F5B84A;
  --info: #8DB4FF;
  --lvl-vmbo: #7FB2FF;
  --lvl-havo: #F5B84A;
  --lvl-vwo: #BFA6FF;
  --lift: none;
}

/* ---------- Light = schrift ---------- */
:root[data-theme="light"] {
  color-scheme: light;
  --paper: #FAFAF7;
  --surface: #FFFFFF;
  --sunk: #F1F1EC;
  --grid: rgba(47, 93, 168, 0.10);
  --margin-rule: rgba(196, 30, 42, 0.35);
  --ink: #1B1D22;
  --ink-2: #474C55;
  --ink-3: #61666F;
  --line: rgba(27, 29, 34, 0.12);
  --line-strong: rgba(27, 29, 34, 0.24);
  --pen: #C41E2A;
  --pen-strong: #B01C27;
  --pen-wash: rgba(196, 30, 42, 0.08);
  --ok: #0B6B4C;
  --ok-wash: rgba(11, 107, 76, 0.09);
  --warn: #8A5000;
  --info: #1D4F9E;
  --lvl-vmbo: #1F5FBF;
  --lvl-havo: #8C5300;
  --lvl-vwo: #6B3FD1;
  --lift: 0 1px 0 rgba(0, 0, 0, 0.04), 0 10px 24px -18px rgba(20, 24, 32, 0.35);
}

/* ---------- Legacy aliases ----------
   Old token names used by the legacy layer and by engines (sim, practice,
   video, search). Each maps onto the new system so the whole site switches at
   once; aliases are deleted as components are rebuilt. */
:root,
:root[data-theme="dark"],
:root[data-theme="light"] {
  --bg: var(--paper);
  --bg-1: var(--surface);
  --bg-2: var(--sunk);
  --glass: var(--surface);
  --line-2: var(--line-strong);
  --text: var(--ink);
  --text-dim: var(--ink-2);
  --text-mute: var(--ink-3);
  --text-muted: var(--ink-2);
  --accent: var(--pen);
  --accent-fill: var(--ink);
  --accent-contrast: var(--paper);
  --accent-glow: transparent;
  --accent-soft: var(--pen-wash);
  --link: var(--ink);
  --link-hover: var(--ink);
  --link-underline: color-mix(in srgb, var(--pen) 50%, transparent);
  --link-marker: var(--pen-wash);
  --shadow-1: var(--lift);
  --shadow-soft: none;
  --shadow-nav: none;
  --shadow-card: var(--lift);
  --surface-raised: var(--surface);
  --surface-sunken: var(--sunk);
  --border: var(--line);
  --ok-soft: var(--ok-wash);
  --error: var(--pen-strong);
  --error-soft: var(--pen-wash);
  --focus-ring: var(--pen);
  --niveau-vmbo: var(--lvl-vmbo);
  --niveau-havo: var(--lvl-havo);
  --niveau-vwo: var(--lvl-vwo);
  --niveau-vmbo-soft: color-mix(in srgb, var(--lvl-vmbo) 12%, var(--surface));
  --niveau-havo-soft: color-mix(in srgb, var(--lvl-havo) 12%, var(--surface));
  --niveau-vwo-soft: color-mix(in srgb, var(--lvl-vwo) 12%, var(--surface));
  --r-xs: var(--r-1);
  --r-sm: var(--r-1);
  --r-md: var(--r-2);
  --r-lg: var(--r-2);
  --radius-sm: var(--r-1);
  --radius-md: var(--r-2);
  --radius-lg: var(--r-2);
  --radius-pill: var(--r-pill);
  --fs-hero: var(--fs-2xl);
  --fs-h2: var(--fs-lg);
  --fs-h3: var(--fs-md);
  --fs-body: var(--fs-base);
  --fs-small: var(--fs-sm);
  --t-fast: var(--t-press);
  --t-base: var(--t-ui);
  --t-slow: var(--t-panel);
  --t-ink: var(--t-draw);
  --ease-pop: var(--ease-out);
  --space-1: var(--s-1); --space-2: var(--s-2); --space-3: var(--s-3); --space-4: var(--s-4);
  --space-5: var(--s-5); --space-6: var(--s-6); --space-7: var(--s-7); --space-8: var(--s-8);
  --container: var(--w-work);
  --content: 72rem;
  --header-offset: 88px;
  --header-gutter: 24px;
  --sim-grid-line: var(--grid);
}
}

/* 10-fonts.css */
/* ==========================================================================
   Fonts (docs/redesign/03 §4, 07 §2)
   Display: Bricolage Grotesque (self-hosted, subset) — swap + metric-matched
   fallback so the brand face actually renders and swapping causes no shift.
   Body/UI: system stack (no web font). Notes: Caveat subset, swap.
   Inter is no longer used (it was declared but never referenced; audit F2).
   ========================================================================== */

@font-face {
  font-family: "Bricolage Grotesque Fallback";
  src: local("Arial");
  size-adjust: 105%;
  ascent-override: 92%;
  descent-override: 22%;
  line-gap-override: 0%;
}

@font-face {
  font-family: "Caveat Fallback";
  src: local("Georgia");
  size-adjust: 118%;
  ascent-override: 88%;
  descent-override: 24%;
  line-gap-override: 0%;
}

@font-face {
  font-family: "Bricolage Grotesque";
  src: url("/assets/fonts/bricolage-grotesque.woff2") format("woff2");
  font-weight: 200 800;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: Caveat;
  src: url("/assets/fonts/caveat.woff2") format("woff2");
  font-weight: 400 700;
  font-style: normal;
  font-display: swap;
}

/* 20-base.css */
@layer base {
/* ==========================================================================
   Base: document, paper, type, links, focus.
   ========================================================================== */

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  background-color: var(--paper);
  /* Squared paper: 24 px squares, aligned to the spacing module. */
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: var(--square) var(--square);
  background-position: -1px -1px;
  scroll-behavior: smooth;
  scroll-padding-top: var(--s-5);
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

body {
  margin: 0;
  background: transparent;
  color: var(--ink);
  font-family: var(--font-body);
  font-size: var(--fs-base);
  line-height: 1.6;
  font-kerning: normal;
  text-rendering: optimizeLegibility;
}

img,
svg,
video {
  max-width: 100%;
}

h1,
h2,
h3 {
  font-family: var(--font-display);
  color: var(--ink);
  text-wrap: balance;
}

h1 {
  font-size: var(--fs-xl);
  font-weight: 750;
  line-height: 1.05;
  letter-spacing: -0.025em;
}

h2 {
  font-size: var(--fs-lg);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.02em;
}

h3 {
  font-size: var(--fs-md);
  font-weight: 650;
  line-height: 1.3;
  letter-spacing: -0.01em;
}

p,
li {
  text-wrap: pretty;
}

math {
  font-family: var(--font-math);
}

a {
  color: var(--ink);
  text-decoration-line: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 0.2em;
  text-decoration-color: color-mix(in srgb, var(--pen) 55%, transparent);
}

a:hover {
  text-decoration-color: var(--pen);
  text-decoration-thickness: 2px;
}

:focus-visible {
  outline: 2px solid var(--pen);
  outline-offset: 2px;
  border-radius: 2px;
}

::selection {
  background: color-mix(in srgb, var(--pen) 22%, transparent);
  color: var(--ink);
}

code,
kbd,
samp {
  font-size: 0.92em;
  font-variant-numeric: tabular-nums;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: absolute;
  left: var(--s-4);
  top: -4rem;
  z-index: 80;
  padding: var(--s-3) var(--s-4);
  background: var(--ink);
  color: var(--paper);
  border-radius: var(--r-1);
  font-weight: 600;
  text-decoration: none;
}

.skip-link:focus {
  top: var(--s-4);
}

.tnum {
  font-variant-numeric: tabular-nums;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 1ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 1ms !important;
  }
}

/* The hidden attribute always wins over component display rules. */
[hidden]:not([hidden="until-found"]) {
  display: none !important;
}
}

/* 50-legacy.css */
@layer legacy {
/* Legacy rules (Red Noir era), migrated component by component in R3–R11.
   Delete a block here when its component is rebuilt in 70-*.css. */

html.js .reveal {
  opacity: 0;
  transition: opacity 520ms var(--ease-out);
  transition-delay: var(--reveal-delay, 0ms);
}

html.js .reveal.is-in,
html.reveal-show .reveal {
  opacity: 1;
  animation: none;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  html.js .reveal {
    opacity: 1;
    transition: none;
  }
}

.container {
  width: min(100% - 2 * var(--gutter), var(--container));
  margin-inline: auto;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.glass {
  background: var(--glass);
  border: 1px solid var(--line-2);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.12);
}

.card {
  background: var(--bg-1);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  box-shadow: var(--shadow-1);
  position: relative;
}

.reveal {
  animation: none;
}

@keyframes reveal-up {
  from {
    opacity: 0;
    transform: translateY(14px);
  }

  to {
    opacity: 1;
    transform: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .reveal {
    animation: none;
  }
}

.hero {
  padding: 1.5rem 0 2.5rem;
}

.hero.home-fade {
  animation: none;
}

.hero h1,
.page-title {
  font-family: var(--font-display);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.08;
  font-size: clamp(2rem, 5vw, 3.5rem);
  margin: 0 0 1rem;
}

.lede {
  font-size: 1.15rem;
  color: var(--text-muted);
  max-width: 40rem;
  margin: 0 0 1.5rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.section {
  padding: 2.25rem 0;
}

/* #onderwerpen renders eagerly: it follows the Phase 10 chooser and its
   real height (~3300px on phones) is far above any intrinsic-size guess. */
#rekenmachines,
.home-path,
.home-sources-section,
#faq,
#voorbeelden,
#fouten,
#oefenen,
#examples,
#mistakes,
#practice,
.below-fold {
  content-visibility: auto;
  contain-intrinsic-size: auto 28rem;
}

.section h2,
.prose h2 {
  font-family: var(--font-display);
  letter-spacing: -0.04em;
  font-size: 1.65rem;
  margin: 0 0 1rem;
}

.prose {
  font-family: var(--font-body);
}

#onderwerpen .card-grid,
#rekenmachines .card-grid {
  grid-template-columns: 1fr;
}

@media (min-width: 768px) {
  #onderwerpen .card-grid,
  #rekenmachines .card-grid {
    grid-template-columns: 1fr 1fr;
  }

  #onderwerpen .topic-card--lead {
    grid-column: 1 / -1;
  }
}

@media (min-width: 1024px) {
  #onderwerpen .card-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  #onderwerpen .topic-card--lead {
    grid-column: span 2;
  }

  #rekenmachines .card-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.path-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  padding: 0;
  margin: 0 0 1rem;
  list-style: none;
  counter-reset: path-step;
}

.path-list li {
  counter-increment: path-step;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  min-height: 44px;
  padding: 0.45rem 0.9rem 0.45rem 0.7rem;
  background: var(--bg-1);
  border: 1px solid var(--line-2);
  border-radius: var(--r-2);
  font-weight: 600;
}

.path-list li::before {
  content: counter(path-step);
  font-variant-numeric: tabular-nums;
  color: var(--accent);
  min-width: 1.15ch;
}

.home-sources {
  padding: 1.15rem 1.25rem 1.35rem;
  background: var(--bg-1);
  border: 1px solid var(--line-2);
  border-radius: var(--r-2);
}

.home-sources p:last-child {
  margin-bottom: 0;
}

.home-note {
  margin: 0.85rem 0 0;
  font-family: var(--font-note);
  font-size: 1.15rem;
  color: var(--accent);
  transform: rotate(-3deg);
  transform-origin: left center;
  width: fit-content;
}

.ask-form {
  display: grid;
  gap: 0.75rem;
  margin-bottom: 1.25rem;
}

.ask-form .calc-control textarea {
  min-height: 6rem;
}

.ask-status {
  min-height: 1.5rem;
  color: var(--text-mute);
}

.ask-status:not(:empty) {
  margin-bottom: 0.75rem;
}

/* S2-P6: "Dat kan ik nog niet" suggestions, touch targets >= 44px */
#ask-suggest ul {
  margin: 0.25rem 0 1rem;
  padding: 0;
  list-style: none;
}

#ask-suggest a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
}

.calc-expr {
  width: 100%;
  min-height: 52px;
  border: 1px solid var(--line-2);
  border-radius: var(--r-sm);
  padding: 0.7rem 0.8rem;
  font: inherit;
  font-size: 1.15rem;
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum", "cv11";
  background: var(--bg-2);
  color: var(--text);
}

.calc-keypad {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.4rem;
  margin: 0.8rem 0;
}

.calc-fnpad:not([hidden]) {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.4rem;
  margin: 0.8rem 0;
}

.calc-keypad button,
.calc-fnpad button {
  min-height: 48px;
  border: 1px solid var(--line);
  border-radius: var(--r-sm);
  background: var(--bg-1);
  color: var(--text);
  font: inherit;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  cursor: pointer;
}

.calc-keypad button.is-op,
.calc-fnpad button.is-op {
  color: var(--accent);
}

.calc-keypad button.is-accent,
.calc-fnpad button.is-accent {
  background: var(--accent-fill);
  color: var(--accent-contrast);
  border-color: var(--accent-fill);
}

.calc-keypad button:active,
.calc-fnpad button:active {
  transform: scale(0.97);
}

.calc-angle:not([hidden]) {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin: 0.6rem 0;
}

.calc-angle .btn {
  position: relative;
}

.calc-angle .is-active {
  background: var(--bg-1);
  color: var(--text);
  border-color: var(--line-2);
}

.calc-angle .is-active::after {
  content: "";
  position: absolute;
  left: 0.8rem;
  right: 0.8rem;
  bottom: 0.35rem;
  height: 1.5px;
  border-radius: 1px;
  background: var(--accent);
  transform: rotate(-1.4deg);
}

.calc-plot {
  display: block;
  width: 100%;
  height: 280px;
  background: var(--bg-2);
  border: 1px solid var(--line-2);
  border-radius: var(--r-2);
  margin: 0.8rem 0;
}

.plot-table {
  width: 100%;
  border-collapse: collapse;
  font-variant-numeric: tabular-nums;
}

.plot-table th,
.plot-table td {
  border-bottom: 1px solid var(--border);
  padding: 0.4rem 0.5rem;
  text-align: left;
}

.prose > * + * {
  margin-top: 0.9rem;
}

.prose h3 {
  font-family: var(--font-display);
  margin-top: 1.8rem;
}

@media (max-width: 800px) {
  .hero {
    padding-top: 1.25rem;
  }

  .calc-keypad {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (max-width: 600px) {
  :root {
    --header-gutter: 12px;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .hero.home-fade,
  .btn,
  .btn-primary,
  .topic-card,
  .related-card,
  .calculator-shell,
  .lang-switch::before,
  .nav-drop > summary::before,
  .nav-primary > a::before,
  .nav-chevron,
  .nav-drop-list,
  .nav-toggle:active,
  .theme-toggle:active,
  .footer-cta .btn:active,
  .site-header .brand:hover .brand-mark,
  html.js .brand.is-inking .brand-pen,
  .site-footer h2::after,
  .home-note,
  .faq-chevron,
  .faq details p,
  .faq summary:not(:has(.faq-chevron))::after,
  .calc-tab::after,
  .example-tabs [role="tab"]::after,
  .toc a::after,
  .calc-keypad button,
  .calc-fnpad button,
  .btn:active,
  html.js .calc-ink .ink-path {
    animation: none;
    transition: none;
    transform: none;
  }

  .nav-drop > summary::before,
  .nav-primary > a::before,
  .nav-drop:has([aria-current="page"]) > summary::before,
  .nav-primary > a[aria-current="page"]::before,
  .topic-card h3::after,
  .related-card h3::after,
  .calc-tab.is-active::after,
  .example-tabs [role="tab"].is-active::after,
  .calc-tab[aria-selected="true"]::after,
  .example-tabs [role="tab"][aria-selected="true"]::after,
  .toc a:hover::after,
  .toc a:focus-visible::after {
    transform: scaleX(1) rotate(-1.4deg);
  }

  .site-footer h2::after {
    transform: rotate(-1.4deg);
  }

  html.js .brand.is-inking .brand-pen {
    stroke-dashoffset: 0;
  }

  html.js .calc-ink .ink-path,
  html.js .calc-ink.is-ink .ink-path {
    stroke-dashoffset: 0;
    transition: none;
  }

  .btn-primary {
    background:
      linear-gradient(var(--btn-fill), var(--btn-fill)) padding-box,
      linear-gradient(var(--accent), var(--accent)) border-box;
  }

  .topic-card:hover,
  .topic-card:focus-visible,
  .related-card:hover,
  .related-card:focus-visible,
  .btn-primary:hover,
  .btn-primary:focus-visible,
  .home-note,
  .faq details p,
  .faq-chevron {
    transform: none;
    box-shadow: var(--shadow-soft);
  }

  .faq details[open] p,
  .faq details[open] .faq-chevron,
  .faq details[open] summary:not(:has(.faq-chevron))::after {
    transform: none;
  }

  .faq details[open] .faq-chevron,
  .faq details[open] summary:not(:has(.faq-chevron))::after {
    transform: rotate(180deg);
  }
}

@keyframes fade-up {
  from {
    opacity: 0;
  }

  to {
    opacity: 1;
  }
}
}

/* 60-layout.css */
@layer layout {
/* ==========================================================================
   Layout primitives (docs/redesign/04 §1).
   ========================================================================== */

.wrap {
  width: min(100% - 2 * var(--gutter), 72rem);
  margin-inline: auto;
}

.container {
  width: min(100% - 2 * var(--gutter), var(--w-work));
  margin-inline: auto;
}

.stack > * + * {
  margin-top: var(--s-4);
}

.cluster {
  display: flex;
  flex-wrap: wrap;
  gap: var(--s-2) var(--s-3);
  align-items: center;
}

body.nav-open {
  overflow: hidden;
}

/* Content pages: sticky "Op deze pagina" column from 1024 px, one column below. */
.page-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--s-6);
  padding: var(--s-4) 0 var(--s-8);
}

.page-layout > article,
.page-layout > main {
  min-width: 0;
  container-type: inline-size;
}

/* No contents column on this page (e.g. the EN home): the article spans it all. */
.page-layout > :only-child {
  grid-column: 1 / -1;
}

.page-simple {
  max-width: 44rem;
  padding: var(--s-4) 0 var(--s-8);
}

.toc {
  display: none;
}

@media (min-width: 1024px) {
  .page-layout {
    grid-template-columns: 11rem minmax(0, 1fr);
    gap: var(--s-6) var(--s-7);
    padding-top: var(--s-5);
  }

  .toc {
    position: sticky;
    top: calc(64px + var(--s-5));
    align-self: start;
    display: block;
    font-size: var(--fs-sm);
  }

  .toc p {
    margin: 0 0 var(--s-2);
    font-size: var(--fs-xs);
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--ink-3);
  }

  .toc a {
    display: block;
    padding: 6px 0 6px var(--s-3);
    border-left: 1.5px solid var(--line);
    color: var(--ink-2);
    text-decoration: none;
    line-height: 1.35;
  }

  .toc a:hover {
    color: var(--ink);
    border-left-color: var(--ink);
  }

  .toc a[aria-current="true"] {
    color: var(--ink);
    border-left-color: var(--pen);
  }
}

/* Workbench (T-CALC): the tool, with the teacher's margin beside it once the
   article is wide enough; below that the margin follows the tool. */
.workbench {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0 var(--s-6);
}

.workbench__tool > h2 {
  margin-top: 0;
}

@container (min-width: 760px) {
  .workbench {
    grid-template-columns: minmax(0, 1fr) 15rem;
    align-items: start;
  }

  .workbench__margin {
    position: sticky;
    top: calc(64px + var(--s-5));
    margin-top: var(--s-8);
    padding-left: var(--s-5);
    border-left: 1.5px solid var(--margin-rule);
  }
}
}

/* 70-buttons.css */
@layer components {
/* ==========================================================================
   Buttons (docs/redesign/04 §2). Graphite UI; red is teacher ink, never a fill.
   primary = ink fill · secondary = outline · text = quiet link-button
   ========================================================================== */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--s-2);
  min-height: 44px;
  padding: 10px 18px;
  border: 1.5px solid transparent;
  border-radius: var(--r-2);
  font: inherit;
  font-weight: 600;
  line-height: 1.2;
  text-decoration: none;
  cursor: pointer;
  transition:
    transform var(--t-press) var(--ease-out),
    background-color var(--t-ui) ease,
    border-color var(--t-ui) ease;
}

.btn:active {
  transform: scale(0.97);
}

.btn-primary,
:root:not([data-theme="light"]) .btn-primary {
  color: var(--paper);
  background: var(--ink);
  border-color: var(--ink);
  box-shadow: none;
}

.btn-primary::before {
  content: none;
}

.btn-primary:hover,
.btn-primary:focus-visible {
  background: color-mix(in srgb, var(--ink) 86%, var(--paper));
  box-shadow: none;
}

.btn-secondary {
  color: var(--ink);
  background: var(--surface);
  border-color: var(--line-strong);
}

.btn-secondary:hover,
.btn-secondary:focus-visible {
  border-color: var(--ink);
}

.btn-text {
  min-height: 44px;
  padding-inline: var(--s-2);
  color: var(--ink);
  background: transparent;
  border: 0;
  text-decoration: underline;
  text-decoration-color: var(--pen);
  text-underline-offset: 0.2em;
}

.btn[disabled],
.btn[aria-disabled="true"] {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  .btn:active {
    transform: none;
  }
}
}

/* 70-chrome.css */
@layer components {
/* ==========================================================================
   Site header, navigation, search panel, footer (docs/redesign/04, 05 §1).
   Markup: scripts/build-chrome.mjs. Behaviour: assets/js/theme.js.
   Desktop bar ≥ 1120 px; below that the nav is a sheet behind the menu button.
   ========================================================================== */

/* Precision instrument: sticky with a negative top, so the bar glides up 12 px
   and locks at 52 px without changing any layout (no CLS, no JS). Once it
   locks, a hairline shadow and a red-pen reading gauge appear (scroll-driven;
   browsers without scroll timelines simply show neither). */
html {
  scroll-padding-top: 72px;
}

.site-header {
  position: sticky;
  top: -12px;
  z-index: var(--z-header);
  padding-top: 12px;
  background: var(--paper);
  border-bottom: 1px solid var(--line);
}

.site-header::after {
  content: "";
  position: absolute;
  inset: auto 0 -1px;
  height: 2px;
  background: var(--pen);
  transform: scaleX(0);
  transform-origin: 0 50%;
  pointer-events: none;
}

@supports (animation-timeline: scroll()) {
  .site-header {
    animation: header-lock linear both;
    animation-timeline: scroll(root);
    animation-range: 0 24px;
  }

  .site-header::after {
    animation: header-gauge linear both;
    animation-timeline: scroll(root);
  }
}

@keyframes header-lock {
  to {
    box-shadow: 0 12px 24px -22px rgba(10, 14, 22, 0.55);
  }
}

@keyframes header-gauge {
  to {
    transform: scaleX(1);
  }
}

.site-header__bar {
  display: flex;
  align-items: center;
  gap: var(--s-4);
  width: min(100% - 2 * var(--gutter), var(--w-wide));
  min-height: 52px;
  margin-inline: auto;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--s-2);
  min-height: 44px;
  color: var(--ink);
  text-decoration: none;
  white-space: nowrap;
}

.brand-mark {
  width: 28px;
  height: 28px;
  flex: none;
  overflow: visible;
}

.brand-pen {
  stroke: var(--pen);
}

.brand-word {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1;
}

/* ---------- nav ---------- */

.site-nav {
  position: relative;
  flex: 1;
}

/* The red pen under the nav: one 1 px line scaled to the hovered item. */
.nav-pen {
  display: none;
}

@media (min-width: 1120px) {
  .nav-pen {
    display: block;
    position: absolute;
    bottom: 5px;
    left: 0;
    width: 1px;
    height: 2px;
    background: var(--pen);
    opacity: 0;
    transform-origin: 0 50%;
    pointer-events: none;
    transition:
      transform 360ms var(--ease-out),
      opacity var(--t-ui) ease;
  }

  .nav-pen.is-still {
    transition: none;
  }

  .has-pen .site-nav__link[aria-current="page"],
  .has-pen .site-nav__link[data-current="true"] {
    text-decoration: none;
  }

  .site-nav__link:hover {
    background: transparent;
  }
}

.site-nav__list {
  display: flex;
  align-items: center;
  gap: var(--s-1);
  margin: 0;
  padding: 0;
  list-style: none;
}

.site-nav__list > li {
  position: relative;
}

.site-nav__link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 44px;
  padding: 0 var(--s-3);
  border: 0;
  border-radius: var(--r-1);
  background: transparent;
  color: var(--ink-2);
  font: inherit;
  font-size: var(--fs-sm);
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
}

.site-nav__link:hover {
  color: var(--ink);
  background: var(--sunk);
}

.site-nav__link[aria-current="page"],
.site-nav__link[data-current="true"],
.site-nav__link[aria-expanded="true"] {
  color: var(--ink);
}

.site-nav__link[aria-current="page"],
.site-nav__link[data-current="true"] {
  text-decoration: underline;
  text-decoration-color: var(--pen);
  text-decoration-thickness: 2px;
  text-underline-offset: 0.45em;
}

.chev {
  width: 12px;
  height: 12px;
  transition: transform var(--t-ui) var(--ease-out);
}

.site-nav__link[aria-expanded="true"] .chev {
  transform: rotate(180deg);
}

.site-nav__menu {
  position: absolute;
  top: calc(100% + 6px);
  left: 0;
  z-index: var(--z-drop);
  min-width: 15rem;
  padding: var(--s-3);
  background: var(--surface);
  border: 1px solid var(--line-strong);
  border-radius: var(--r-2);
  box-shadow: var(--lift), 0 16px 40px -24px rgba(0, 0, 0, 0.45);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-4px);
  transform-origin: top left;
  transition:
    opacity 140ms ease-out,
    transform 140ms var(--ease-out),
    visibility 0s linear 140ms;
}

.site-nav__drop.is-open > .site-nav__menu {
  opacity: 1;
  visibility: visible;
  transform: none;
  transition:
    opacity var(--t-ui) ease-out,
    transform var(--t-ui) var(--ease-out),
    visibility 0s;
}

.site-nav__menu--wide {
  display: grid;
  grid-template-columns: repeat(5, minmax(9.5rem, 1fr));
  gap: var(--s-2) var(--s-5);
  width: min(58rem, calc(100vw - 2 * var(--gutter)));
  padding: var(--s-5);
}

.site-nav__menu ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

.site-nav__menu a {
  display: flex;
  align-items: center;
  min-height: 40px;
  padding: 0 var(--s-2);
  margin-inline: calc(-1 * var(--s-2));
  border-radius: var(--r-1);
  color: var(--ink);
  text-decoration: none;
}

.site-nav__menu a:hover {
  background: var(--sunk);
}

.site-nav__menu a[aria-current="page"] {
  box-shadow: inset 2px 0 0 var(--pen);
  background: var(--pen-wash);
}

.site-nav__group-title {
  margin: 0 0 var(--s-1);
  font-size: var(--fs-xs);
  font-weight: 700;
  color: var(--ink-3);
  letter-spacing: 0.02em;
}

/* second block in a narrow menu (Onderwerpen → Per niveau) */
.site-nav__menu ul + .site-nav__group-title {
  margin-top: var(--s-3);
  padding-top: var(--s-3);
  border-top: 1px solid var(--line);
}

.site-nav__foot {
  grid-column: 1 / -1;
  margin: var(--s-2) 0 0;
  padding-top: var(--s-3);
  border-top: 1px solid var(--line);
}

/* ---------- tools ---------- */

.site-header__tools {
  display: flex;
  align-items: center;
  gap: var(--s-1);
  margin-left: auto;
}

.icon-btn {
  display: inline-grid;
  place-items: center;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 0;
  border-radius: var(--r-1);
  background: transparent;
  color: var(--ink);
  cursor: pointer;
  transition: transform var(--t-press) var(--ease-out);
}

.icon-btn svg {
  width: 22px;
  height: 22px;
}

.icon-btn:hover {
  background: var(--sunk);
}

.icon-btn:active {
  transform: scale(0.95);
}

.icon-btn[aria-expanded="true"] {
  background: var(--sunk);
}

.theme-icon {
  width: 20px;
  height: 20px;
}

:root[data-theme="dark"] .theme-icon--sun,
:root[data-theme="light"] .theme-icon--moon {
  display: none;
}

.lang-switch {
  display: inline-flex;
  padding: 2px;
  border: 1px solid var(--line);
  border-radius: var(--r-1);
}

.lang-switch a {
  display: inline-grid;
  place-items: center;
  min-width: 40px;
  min-height: 40px;
  border-radius: 3px;
  color: var(--ink-3);
  font-size: var(--fs-xs);
  font-weight: 700;
  text-decoration: none;
}

.lang-switch a[aria-current="true"] {
  background: var(--ink);
  color: var(--paper);
}

.nav-toggle {
  display: none;
}

/* Search trigger: a field-shaped button with its keyboard shortcut. */
.search-trigger {
  display: inline-flex;
  align-items: center;
  gap: var(--s-2);
  height: 40px;
  padding: 0 6px 0 var(--s-3);
  border: 1px solid var(--line-strong);
  border-radius: var(--r-2);
  background: var(--surface);
  color: var(--ink-3);
  font: inherit;
  font-size: var(--fs-sm);
  cursor: pointer;
  transition:
    border-color var(--t-ui) ease,
    color var(--t-ui) ease;
}

.search-trigger svg {
  width: 18px;
  height: 18px;
  flex: none;
  color: var(--ink-2);
}

.search-trigger__label {
  min-width: 6.5rem;
  text-align: left;
}

.search-trigger:hover,
.search-trigger[aria-expanded="true"] {
  border-color: var(--ink-3);
  color: var(--ink-2);
}

.search-trigger__kbd,
.site-search-keys kbd {
  padding: 1px 6px;
  border: 1px solid var(--line-strong);
  border-bottom-width: 2px;
  border-radius: var(--r-1);
  background: var(--paper);
  color: var(--ink-2);
  font-family: var(--font-body);
  font-size: 0.75rem;
  font-weight: 600;
  line-height: 1.5;
}

@media (max-width: 1279px) {
  .search-trigger__label {
    display: none;
  }
}

@media (max-width: 1119px) {
  .search-trigger {
    justify-content: center;
    width: 44px;
    height: 44px;
    padding: 0;
    border-color: transparent;
    background: transparent;
  }

  .search-trigger svg {
    width: 22px;
    height: 22px;
    color: var(--ink);
  }

  .search-trigger__kbd {
    display: none;
  }
}

/* ---------- search palette ---------- */

.site-search-panel {
  position: absolute;
  top: calc(100% + var(--s-2));
  right: 0;
  left: 0;
  z-index: var(--z-search);
  pointer-events: none;
}

.site-search-panel > .site-search {
  width: min(100% - 2 * var(--gutter), 40rem);
  margin-inline: auto;
  padding: var(--s-3);
  background: var(--surface);
  border: 1px solid var(--line-strong);
  border-radius: var(--r-2);
  box-shadow:
    0 2px 6px rgba(0, 0, 0, 0.06),
    0 28px 48px -28px rgba(10, 14, 22, 0.55);
  pointer-events: auto;
  animation: palette-in var(--t-ui) var(--ease-out);
}

@keyframes palette-in {
  from {
    opacity: 0;
    transform: translateY(-6px) scale(0.985);
  }
}

.site-search-keys {
  display: flex;
  flex-wrap: wrap;
  gap: var(--s-2) var(--s-5);
  margin: var(--s-3) 0 0;
  padding-top: var(--s-2);
  border-top: 1px solid var(--line);
  color: var(--ink-3);
  font-size: var(--fs-xs);
}

.site-search-keys kbd {
  margin-right: 2px;
}

@media (pointer: coarse) {
  .site-search-keys {
    display: none;
  }
}

.site-search-panel .site-search-row svg {
  width: 20px;
  height: 20px;
  flex: none;
  color: var(--ink-3);
}

/* ---------- small screens: nav becomes a sheet ---------- */

@media (max-width: 1119px) {
  .site-header__bar {
    gap: var(--s-2);
  }

  .nav-toggle {
    display: inline-grid;
  }

  .site-nav {
    position: fixed;
    inset: 64px 0 0;
    /* theme.js sets top to the header's bottom edge when the sheet opens */
    z-index: var(--z-dialog);
    display: none;
    overflow-y: auto;
    padding: var(--s-4) var(--gutter) var(--s-8);
    background: var(--paper);
    border-top: 1px solid var(--line);
  }

  .site-nav.is-open {
    display: block;
  }

  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }

  .site-nav__list > li {
    border-bottom: 1px solid var(--line);
  }

  .site-nav__link {
    width: 100%;
    min-height: 52px;
    justify-content: space-between;
    padding: 0;
    font-size: var(--fs-md);
    font-family: var(--font-display);
    color: var(--ink);
  }

  .site-nav__link:hover {
    background: transparent;
  }

  .site-nav__menu,
  .site-nav__menu--wide {
    position: static;
    display: none;
    width: auto;
    min-width: 0;
    padding: 0 0 var(--s-4);
    border: 0;
    box-shadow: none;
    background: transparent;
    opacity: 1;
    visibility: visible;
    transform: none;
    transition: none;
  }

  .site-nav__drop.is-open > .site-nav__menu {
    display: grid;
  }

  .site-nav__menu--wide {
    grid-template-columns: repeat(auto-fill, minmax(9rem, 1fr));
    gap: var(--s-4);
  }

  .site-nav__menu a {
    min-height: 44px;
  }

  .site-header .lang-switch a {
    min-width: 36px;
  }
}

.site-nav__lang {
  display: none;
}

@media (max-width: 1119px) {
  .site-nav__lang {
    display: block;
    padding: var(--s-4) 0;
  }
}

@media (max-width: 480px) {
  .site-header__tools > .lang-switch {
    display: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .site-nav__menu,
  .chev,
  .nav-pen {
    transition: none;
  }

  .site-search-panel > .site-search {
    animation: none;
  }
}
}

/* 71-forms.css */
@layer components {
/* ==========================================================================
   Tool panel, tabs, input fields (docs/redesign/04 §2).
   Graphite UI: tabs and inputs are ink; the red pen is kept for marks.
   Markup: calculator-core.js (calc-*), page HTML (.example-tabs), ui/tabs.js.
   ========================================================================== */

.calculator-shell {
  margin: var(--s-4) 0 var(--s-6);
  padding: var(--s-5);
  background: var(--surface);
  border: 1.5px solid var(--line-strong);
  border-radius: var(--r-2);
  box-shadow: var(--lift);
}

#calculator {
  min-height: 22rem;
}

/* In the workbench the quick answer sits right below the tool, so reserve
   the smallest mounted height measured in R5 (571 px one column, 441 px two
   columns) until calculator-core mounts; :empty stops matching on mount. */
.workbench #calculator:empty {
  min-height: 35rem;
}

@container (min-width: 760px) {
  .workbench #calculator:empty {
    min-height: 27rem;
  }
}

@media (max-width: 479px) {
  .calculator-shell {
    padding: var(--s-4);
  }
}

/* Tabs: calculator modes and worked-example levels share one look. */
.calc-tabs,
.example-tabs [role="tablist"] {
  display: flex;
  flex-wrap: wrap;
  gap: 0 var(--s-1);
  margin: 0 0 var(--s-5);
  border-bottom: 1px solid var(--line);
}

/* Phones: one scrollable row instead of three wrapped rows. The thin scrollbar stays
   visible so students see there are more modes (volume has 8 since L5). */
@media (max-width: 639px) {
  .calc-tabs {
    flex-wrap: nowrap;
    overflow-x: auto;
    scrollbar-width: thin;
    scrollbar-color: var(--line-2) transparent;
    margin-inline: calc(-1 * var(--s-4));
    padding-inline: var(--s-4);
    padding-bottom: 2px;
    scroll-padding-inline: var(--s-4);
  }

  .calc-tabs::-webkit-scrollbar {
    height: 4px;
  }

  .calc-tabs::-webkit-scrollbar-thumb {
    background: var(--line-2);
    border-radius: 2px;
  }

  .calc-tab {
    flex: none;
    white-space: nowrap;
  }
}

.calc-tab,
.example-tabs [role="tab"] {
  position: relative;
  min-height: 44px;
  margin-bottom: -1px;
  padding: var(--s-2) 10px;
  border: 0;
  border-bottom: 2px solid transparent;
  border-radius: var(--r-1) var(--r-1) 0 0;
  background: transparent;
  color: var(--ink-2);
  font: inherit;
  font-size: var(--fs-sm);
  font-weight: 600;
  cursor: pointer;
  transition:
    color var(--t-ui) ease,
    border-color var(--t-ui) ease;
}

.calc-tab:hover,
.example-tabs [role="tab"]:hover {
  color: var(--ink);
}

.calc-tab.is-active,
.calc-tab[aria-selected="true"],
.example-tabs [role="tab"].is-active,
.example-tabs [role="tab"][aria-selected="true"] {
  color: var(--ink);
  border-bottom-color: var(--ink);
}

.calc-tab::after,
.example-tabs [role="tab"]::after {
  content: none;
}

.example-tabs [role="tabpanel"] {
  padding-top: var(--s-2);
}

/* Fields */
.calc-fields {
  display: grid;
  gap: var(--s-4);
}

@media (min-width: 640px) {
  .calc-fields:has(> .calc-field:nth-child(2)):not(:has(textarea)) {
    grid-template-columns: repeat(auto-fit, minmax(14rem, 1fr));
  }
}

.calc-field label {
  display: block;
  margin-bottom: var(--s-1);
  font-size: var(--fs-sm);
  font-weight: 600;
  color: var(--ink);
}

.calc-control {
  display: flex;
  align-items: center;
  gap: var(--s-2);
}

.calc-control input,
.calc-control textarea,
.calc-select {
  flex: 1;
  width: 100%;
  min-width: 0;
  min-height: 48px;
  padding: 10px 12px;
  border: 1.5px solid var(--line-strong);
  border-radius: var(--r-1);
  background: var(--sunk);
  color: var(--ink);
  font: inherit;
  font-size: max(16px, var(--fs-base));
  font-variant-numeric: tabular-nums;
  transition: border-color var(--t-ui) ease, background-color var(--t-ui) ease;
}

.calc-control input:hover,
.calc-control textarea:hover,
.calc-select:hover {
  border-color: color-mix(in srgb, var(--ink) 45%, transparent);
}

.calc-control input:focus,
.calc-control textarea:focus,
.calc-select:focus {
  border-color: var(--ink);
  background: var(--surface);
}

.calc-control input[aria-invalid="true"],
.calc-control textarea[aria-invalid="true"] {
  border-color: var(--pen-strong);
}

.calc-control textarea {
  min-height: 5.5rem;
  resize: vertical;
  line-height: 1.5;
}

.calc-select {
  display: block;
  max-width: 10rem;
  margin-top: var(--s-1);
}

.calc-unit {
  flex: none;
  min-width: 1ch;
  color: var(--ink-2);
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}

.calc-sign {
  flex: none;
  min-width: 48px;
  min-height: 48px;
  padding: 0;
  font-size: var(--fs-md);
}

.calc-hint,
.calc-echo,
.calc-error {
  margin: var(--s-1) 0 0;
  font-size: var(--fs-sm);
  line-height: 1.45;
}

.calc-hint,
.calc-echo {
  color: var(--ink-3);
}

/* Error = icon + words, never colour alone. */
.calc-error {
  display: flex;
  gap: var(--s-2);
  align-items: baseline;
  color: var(--pen-strong);
  font-weight: 600;
}

.calc-error[hidden] {
  display: none;
}

.calc-error::before {
  content: "";
  flex: none;
  width: 0.8em;
  height: 0.8em;
  translate: 0 0.08em;
  background-color: currentColor;
  -webkit-mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 12 12'%3E%3Cpath d='M3 3l6 6M9 3l-6 6' fill='none' stroke='black' stroke-width='2' stroke-linecap='round'/%3E%3C/svg%3E") center / contain no-repeat;
  mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 12 12'%3E%3Cpath d='M3 3l6 6M9 3l-6 6' fill='none' stroke='black' stroke-width='2' stroke-linecap='round'/%3E%3C/svg%3E") center / contain no-repeat;
}

.calc-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--s-2) var(--s-3);
  margin: var(--s-5) 0;
}

@media (max-width: 479px) {
  .calc-actions .btn-primary {
    flex: 1 1 100%;
  }
}
}

/* 72-tables.css */
@layer components {
/* ==========================================================================
   Tables (docs/redesign/04 §2): real tables in a focusable scroll region;
   scroll shadows cue horizontal overflow without shrinking text.
   ========================================================================== */

.table-wrap {
  max-width: 100%;
  overflow-x: auto;
  margin: var(--s-4) 0;
  border: 1px solid var(--line);
  border-radius: var(--r-2);
  background:
    linear-gradient(90deg, var(--surface) 30%, transparent) left / 24px 100% no-repeat local,
    linear-gradient(270deg, var(--surface) 30%, transparent) right / 24px 100% no-repeat local,
    radial-gradient(farthest-side at 0 50%, rgba(0, 0, 0, 0.14), transparent) left / 10px 100% no-repeat scroll,
    radial-gradient(farthest-side at 100% 50%, rgba(0, 0, 0, 0.14), transparent) right / 10px 100% no-repeat scroll,
    var(--surface);
}

.table-wrap:focus-visible {
  outline: 2px solid var(--pen);
  outline-offset: 2px;
}

table {
  width: 100%;
  border-collapse: collapse;
  font-variant-numeric: tabular-nums;
  font-size: var(--fs-sm);
}

.table-wrap > table {
  min-width: max-content;
}

table caption {
  caption-side: top;
  padding: var(--s-3) var(--s-4) var(--s-2);
  text-align: left;
  font-weight: 700;
  color: var(--ink);
}

th,
td {
  padding: var(--s-2) var(--s-4);
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--line);
}

thead th {
  font-size: var(--fs-xs);
  font-weight: 700;
  color: var(--ink-2);
  background: var(--sunk);
  white-space: nowrap;
}

tbody tr:last-child > * {
  border-bottom: 0;
}

tbody th {
  font-weight: 600;
}
}

/* 73-result.css */
@layer components {
/* ==========================================================================
   Result panel, answer circle, step ladder, margin note (docs/redesign/03 §6).
   The answer sits on a strip of squared paper behind a red margin rule; the
   red ellipse (ink.js) is the one expressive animation on tool pages.
   ========================================================================== */

.calc-result {
  position: relative;
  min-height: 8.5rem;
  padding: var(--s-4) var(--s-5) var(--s-4) calc(var(--s-5) + var(--s-3));
  border: 1px solid var(--line);
  border-radius: var(--r-2);
  background-color: var(--paper);
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: var(--square) var(--square);
}

/* Notebook margin rule */
.calc-result::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: var(--s-5);
  width: 1.5px;
  background: var(--margin-rule);
}

.calc-result-label {
  margin: 0;
  font-size: var(--fs-xs);
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-3);
}

.calc-result-value {
  position: relative;
  margin: var(--s-2) 0 var(--s-1);
  padding-inline-start: 0.3em;
  font-family: var(--font-display);
  font-size: var(--fs-xl);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.03em;
  font-variant-numeric: tabular-nums;
  overflow-wrap: anywhere;
}

.calc-result-value.is-accent {
  color: var(--ink);
}

.calc-result-value.is-error {
  color: var(--pen-strong);
  font-family: var(--font-body);
  font-size: var(--fs-md);
  font-weight: 600;
  letter-spacing: 0;
}

.calc-result-note,
.calc-result-hint {
  margin: var(--s-1) 0 0;
  font-size: var(--fs-sm);
  color: var(--ink-2);
}

.calc-result-hint {
  color: var(--ink-3);
}

/* Answer circle / underline (ink.js draws the path; pathLength = 1). */
.calc-ink {
  position: relative;
  display: inline-flex;
  align-items: center;
  width: fit-content;
  max-width: 100%;
}

.calc-ink__text {
  position: relative;
  z-index: 1;
}

.ink-svg {
  position: absolute;
  left: -0.55em;
  top: -0.32em;
  width: calc(100% + 1.1em);
  height: calc(100% + 0.64em);
  overflow: visible;
  pointer-events: none;
}

.ink-path {
  stroke: var(--pen);
  stroke-width: 2.25;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-dasharray: 1;
  stroke-dashoffset: 0;
}

.calc-ink[data-ink="underline"] .ink-path {
  stroke-width: 1.75;
}

html.js .calc-ink:not(.is-ink) .ink-path {
  stroke-dashoffset: 1;
}

html.js .calc-ink.is-ink .ink-path {
  stroke-dashoffset: 0;
}

@media (prefers-reduced-motion: no-preference) {
  html.js .calc-ink.is-ink .ink-path {
    transition: stroke-dashoffset var(--t-draw) var(--ease-draw);
  }
}

/* Base caps svg at 100% of the text box, which would shrink the ellipses. */
.ink-svg,
.hero-ink-svg {
  max-width: none;
}

/* Step ladder: numbered lines on the paper. */
.step-block {
  margin-top: var(--s-5);
}

.step-block-title {
  margin: 0 0 var(--s-3);
  font-size: var(--fs-md);
}

.step-list {
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: step;
  font-variant-numeric: tabular-nums;
}

.step-list > li {
  counter-increment: step;
  display: grid;
  grid-template-columns: 2rem minmax(0, 1fr);
  column-gap: var(--s-3);
  padding: var(--s-3) 0;
  border-bottom: 1px dashed var(--line-strong);
}

.step-list > li:last-child {
  border-bottom: 0;
}

.step-list > li::before {
  content: counter(step);
  grid-row: 1 / span 9;
  display: inline-grid;
  place-items: center;
  width: 1.75rem;
  height: 1.75rem;
  border: 1.5px solid var(--line-strong);
  border-radius: 50%;
  font-size: var(--fs-xs);
  font-weight: 700;
  color: var(--ink-2);
}

/* The last step is the answer: the pen marks it. */
.step-list > li:last-child::before {
  border-color: var(--pen);
  color: var(--pen-strong);
}

.step-list strong {
  display: block;
  font-weight: 600;
  color: var(--ink);
}

.step-list span,
.step-list li > p {
  color: var(--ink-2);
  overflow-wrap: anywhere;
}

/* Margin note: the teacher's handwriting. Real text, never an image. */
.note {
  display: block;
  width: fit-content;
  max-width: 28ch;
  margin: var(--s-2) 0 0;
  font-family: var(--font-note);
  font-size: 1.3rem;
  font-weight: 600;
  line-height: 1.2;
  color: var(--pen-strong);
  rotate: -2deg;
  transform-origin: left center;
}

.note::before {
  content: "\2190\00a0";
}

@media (prefers-reduced-motion: reduce) {
  html.js .calc-ink .ink-path,
  html.js .calc-ink.is-ink .ink-path {
    stroke-dashoffset: 0;
    transition: none;
  }
}
}

/* 74-content.css */
@layer components {
/* ==========================================================================
   Content components (docs/redesign/04 §2): page head, breadcrumbs, badges,
   formula card, callouts, mistake pair, inline practice, FAQ, cards,
   next-step block, sources.
   ========================================================================== */

.muted,
.card-meta,
.byline {
  color: var(--ink-3);
  font-size: var(--fs-sm);
}

/* Page head */
.page-head {
  margin: 0 0 var(--s-2);
}

.page-title {
  margin: var(--s-2) 0 var(--s-4);
}

.lede {
  max-width: 60ch;
  font-size: var(--fs-md);
  line-height: 1.5;
  color: var(--ink-2);
}

.breadcrumbs {
  margin: 0;
  font-size: var(--fs-sm);
  color: var(--ink-2);
}

.breadcrumbs ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  margin: 0;
  padding: 0;
  list-style: none;
}

.breadcrumbs li {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
}

.breadcrumbs li:not(:last-child)::after {
  content: "/";
  margin: 0 var(--s-2);
  color: var(--ink-3);
}

.breadcrumbs a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  color: var(--ink-2);
  text-decoration: none;
}

.breadcrumbs a:hover {
  color: var(--ink);
  text-decoration: underline;
  text-decoration-color: var(--pen);
}

.breadcrumbs [aria-current="page"] {
  color: var(--ink-3);
}

/* Level badges: tinted, outlined, text always present. */
.badge {
  display: inline-flex;
  align-items: center;
  width: fit-content;
  padding: 2px var(--s-2);
  border: 1px solid color-mix(in srgb, currentColor 35%, transparent);
  border-radius: var(--r-1);
  font-size: var(--fs-xs);
  font-weight: 700;
  line-height: 1.4;
  letter-spacing: 0.02em;
}

.badge-vmbo {
  color: var(--lvl-vmbo);
  background: var(--niveau-vmbo-soft);
}

.badge-havo {
  color: var(--lvl-havo);
  background: var(--niveau-havo-soft);
}

.badge-vwo {
  color: var(--lvl-vwo);
  background: var(--niveau-vwo-soft);
}

.badge-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--s-1) var(--s-2);
  margin: var(--s-1) 0 0;
}

/* Formula card (also the "Snel antwoord" block) */
.formula-block {
  position: relative;
  margin: var(--s-4) 0 var(--s-5);
  padding: var(--s-4) var(--s-5) var(--s-4) calc(var(--s-5) + var(--s-3));
  border: 1px solid var(--line);
  border-radius: var(--r-2);
  background: var(--surface);
  font-variant-numeric: tabular-nums;
}

.formula-block::before {
  content: "";
  position: absolute;
  top: var(--s-3);
  bottom: var(--s-3);
  left: var(--s-5);
  width: 1.5px;
  background: var(--margin-rule);
}

.formula-block p {
  margin: var(--s-2) 0 0;
}

.formula-block p:first-child {
  margin-top: 0;
  font-size: var(--fs-xs);
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-3);
}

.formula-block math[display="block"] {
  margin: var(--s-2) 0;
  font-size: 1.15em;
}

/* In the workbench margin the formula card loses its box: the column's margin
   rule already frames it (component layer, so this beats .formula-block). */
@container (min-width: 760px) {
  .workbench__margin .formula-block {
    margin: 0;
    padding: 0;
    border: 0;
    background: none;
    font-size: var(--fs-sm);
  }

  .workbench__margin .formula-block::before {
    content: none;
  }
}

/* Callouts: icon + title + text; the colour is never the only signal. */
.callout,
.notice {
  display: grid;
  grid-template-columns: 1.25rem minmax(0, 1fr);
  gap: var(--s-1) var(--s-3);
  margin: var(--s-4) 0;
  padding: var(--s-4);
  border: 1px solid var(--line);
  border-left: 3px solid var(--callout, var(--info));
  border-radius: var(--r-1) var(--r-2) var(--r-2) var(--r-1);
  background: var(--surface);
}

.callout::before,
.notice::before {
  content: "";
  grid-row: 1 / span 9;
  width: 1.25rem;
  height: 1.25rem;
  translate: 0 0.15em;
  background-color: var(--callout, var(--info));
  -webkit-mask: var(--callout-icon) center / contain no-repeat;
  mask: var(--callout-icon) center / contain no-repeat;
}

.callout > *,
.notice > * {
  grid-column: 2;
  margin: 0;
}

.callout > * + *,
.notice > * + * {
  margin-top: var(--s-1);
}

.callout,
.notice,
.callout[data-variant="info"] {
  --callout: var(--info);
  --callout-icon: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 20 20'%3E%3Ccircle cx='10' cy='10' r='8' fill='none' stroke='black' stroke-width='1.75'/%3E%3Cpath d='M10 9v5M10 6.2v.1' fill='none' stroke='black' stroke-width='1.75' stroke-linecap='round'/%3E%3C/svg%3E");
}

.callout[data-variant="tip"] {
  --callout: var(--ok);
  --callout-icon: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 20 20'%3E%3Cpath d='M7.5 15h5M8 17.5h4M10 2.5a5.5 5.5 0 0 0-3.3 9.9c.5.4.8 1 .8 1.6h5c0-.6.3-1.2.8-1.6A5.5 5.5 0 0 0 10 2.5Z' fill='none' stroke='black' stroke-width='1.75' stroke-linejoin='round' stroke-linecap='round'/%3E%3C/svg%3E");
}

.callout[data-variant="mistake"] {
  --callout: var(--pen-strong);
  --callout-icon: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 20 20'%3E%3Cpath d='M5 5l10 10M15 5 5 15' fill='none' stroke='black' stroke-width='2' stroke-linecap='round'/%3E%3C/svg%3E");
}

.callout[data-variant="exam"] {
  --callout: var(--warn);
  --callout-icon: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 20 20'%3E%3Crect x='4' y='2.5' width='12' height='15' rx='1.5' fill='none' stroke='black' stroke-width='1.75'/%3E%3Cpath d='M7 7h6M7 10h6M7 13h3.5' fill='none' stroke='black' stroke-width='1.75' stroke-linecap='round'/%3E%3C/svg%3E");
}

/* Mistake pair: "Fout" (cross) next to "Goed" (tick). */
.mistake-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--s-3);
}

@media (max-width: 639px) {
  .mistake-grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .mistake-card.good {
    margin-bottom: var(--s-3);
  }
}

.mistake-card {
  padding: var(--s-4);
  border: 1px solid var(--line);
  border-top: 3px solid var(--mark);
  border-radius: var(--r-1) var(--r-1) var(--r-2) var(--r-2);
  background: var(--surface);
}

.mistake-card.bad {
  --mark: var(--pen);
}

.mistake-card.good {
  --mark: var(--ok);
}

.mistake-card > p {
  margin: 0;
}

.mistake-card > p + p {
  margin-top: var(--s-2);
}

.mistake-card > p:first-child {
  display: flex;
  align-items: center;
  gap: var(--s-2);
  color: var(--mark);
}

.mistake-card.bad > p:first-child {
  color: var(--pen-strong);
}

.mistake-card > p:first-child::before {
  content: "";
  flex: none;
  width: 1rem;
  height: 1rem;
  background-color: currentColor;
  -webkit-mask: center / contain no-repeat;
  mask: center / contain no-repeat;
}

.mistake-card.bad > p:first-child::before {
  -webkit-mask-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 12 12'%3E%3Cpath d='M3 3l6 6M9 3l-6 6' fill='none' stroke='black' stroke-width='1.75' stroke-linecap='round'/%3E%3C/svg%3E");
  mask-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 12 12'%3E%3Cpath d='M3 3l6 6M9 3l-6 6' fill='none' stroke='black' stroke-width='1.75' stroke-linecap='round'/%3E%3C/svg%3E");
}

.mistake-card.good > p:first-child::before {
  -webkit-mask-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 12 12'%3E%3Cpath d='M2.5 6.4 5 8.9 9.6 3.4' fill='none' stroke='black' stroke-width='1.75' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
  mask-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 12 12'%3E%3Cpath d='M2.5 6.4 5 8.9 9.6 3.4' fill='none' stroke='black' stroke-width='1.75' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
}

/* Inline practice question with a reveal button */
.practice {
  display: grid;
  gap: var(--s-3);
  justify-items: start;
  margin: var(--s-3) 0;
  padding: var(--s-4);
  border: 1px solid var(--line);
  border-radius: var(--r-2);
  background: var(--surface);
}

.practice > p {
  margin: 0;
}

.practice .badge {
  margin-right: var(--s-2);
  vertical-align: 0.1em;
}

.practice [data-practice-answer] {
  justify-self: stretch;
  padding: var(--s-3) var(--s-4);
  border-left: 1.5px solid var(--margin-rule);
  background: var(--paper);
}

.practice [data-practice-answer] > p {
  margin: 0;
}

.practice [data-practice-answer] > p + p {
  margin-top: var(--s-1);
  color: var(--ink-2);
}

/* FAQ: native details, one rule between questions. */
.faq details {
  border-bottom: 1px solid var(--line);
}

.faq h2 + details {
  border-top: 1px solid var(--line);
}

.faq summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--s-3);
  min-height: 48px;
  padding: var(--s-3) 0;
  font-weight: 600;
  list-style: none;
  cursor: pointer;
}

.faq summary::-webkit-details-marker {
  display: none;
}

.faq summary:hover {
  color: var(--ink);
  text-decoration: underline;
  text-decoration-color: var(--pen);
  text-underline-offset: 0.2em;
}

.faq-chevron {
  flex: none;
  width: 0.75rem;
  height: 0.75rem;
  transition: transform var(--t-ui) var(--ease-out);
}

.faq summary:not(:has(.faq-chevron))::after {
  content: "";
  flex: none;
  width: 0.75rem;
  height: 0.75rem;
  background-color: var(--ink-2);
  -webkit-mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 12 12'%3E%3Cpath d='M2.5 4.25 6 7.75 9.5 4.25' fill='none' stroke='black' stroke-width='1.75' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E") center / contain no-repeat;
  mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 12 12'%3E%3Cpath d='M2.5 4.25 6 7.75 9.5 4.25' fill='none' stroke='black' stroke-width='1.75' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E") center / contain no-repeat;
  transition: transform var(--t-ui) var(--ease-out);
}

.faq details[open] .faq-chevron,
.faq details[open] summary:not(:has(.faq-chevron))::after {
  transform: rotate(180deg);
}

.faq details > p,
.faq details > div {
  max-width: 68ch;
  margin: 0;
  padding: 0 0 var(--s-4);
  color: var(--ink-2);
}

/* Cards: one link, one name; hover only on pointer devices. */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(100%, 15rem), 1fr));
  gap: var(--s-3);
}

.topic-card,
.soon-card,
.info-card,
.related-card {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: var(--s-1);
  min-height: 7.5rem;
  padding: var(--s-4);
  border: 1px solid var(--line);
  border-radius: var(--r-2);
  background: var(--surface);
  color: inherit;
  text-decoration: none;
  transition: border-color var(--t-ui) ease, transform var(--t-ui) var(--ease-out);
}

.topic-card h3,
.soon-card h3,
.info-card h3,
.related-card h3 {
  margin: 0;
  font-size: var(--fs-md);
  line-height: 1.25;
  text-decoration: underline;
  text-decoration-color: transparent;
  text-decoration-thickness: 1.5px;
  text-underline-offset: 0.2em;
  transition: text-decoration-color var(--t-ui) ease;
}

.topic-card p,
.related-card p,
.info-card p {
  margin: 0;
}

.topic-card h3::after,
.related-card h3::after {
  content: none;
}

.topic-card:focus-visible h3,
.related-card:focus-visible h3 {
  text-decoration-color: var(--pen);
}

@media (hover: hover) and (pointer: fine) {
  .topic-card:hover,
  .related-card:hover {
    border-color: var(--line-strong);
    background: var(--surface);
    transform: translateY(-2px);
  }

  .topic-card:hover h3,
  .related-card:hover h3 {
    text-decoration-color: var(--pen);
  }
}

.soon-card {
  color: var(--ink-2);
  border-style: dashed;
}

/* Next step (build-leerpad output) */
.leerpad {
  margin-top: var(--s-7);
}

.leerpad-list {
  display: grid;
  gap: 0;
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line);
}

.leerpad-list li {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0 var(--s-3);
  padding: var(--s-2) 0;
  border-bottom: 1px solid var(--line);
}

.leerpad-list a {
  display: inline-block;
  padding-block: 10px;
  font-weight: 600;
}

/* inline-block keeps the link underline off the arrow */
.leerpad-list a::after {
  content: "\2192";
  display: inline-block;
  margin-inline-start: var(--s-2);
  color: var(--pen);
  transition: translate var(--t-ui) var(--ease-out);
}

.leerpad-list a:hover::after {
  translate: 3px 0;
}

.leerpad-related {
  margin-top: var(--s-3);
}

.leerpad-related a {
  display: inline-block;
  padding-block: 10px;
}

/* Sources and byline */
.source-footer {
  margin-top: var(--s-7);
  padding-top: var(--s-4);
  border-top: 1px solid var(--line);
  color: var(--ink-3);
  font-size: var(--fs-sm);
}

.source-footer p {
  margin: 0 0 var(--s-2);
}

.source-footer a {
  display: inline-block;
  padding-block: 10px;
  margin-block: -10px;
}

@media (prefers-reduced-motion: reduce) {
  .topic-card,
  .related-card,
  .faq-chevron,
  .faq summary::after,
  .leerpad-list a::after {
    transition: none;
  }

  .topic-card:hover,
  .related-card:hover,
  .leerpad-list a:hover::after {
    transform: none;
    translate: none;
  }
}

/* Related tools: a compact link row, not a second card grid. */
.related-tools {
  margin-top: var(--s-6);
}

.related-tools h2 {
  font-size: var(--fs-md);
}

.related-tools .card-grid {
  grid-template-columns: repeat(auto-fill, minmax(min(100%, 16rem), 1fr));
  gap: 0 var(--s-5);
}

.related-tools .related-card {
  min-height: 0;
  padding: var(--s-3) 0;
  border: 0;
  border-top: 1px solid var(--line);
  border-radius: 0;
  background: none;
  transform: none;
}

.related-tools .related-card h3 {
  font-family: var(--font-body);
  font-size: var(--fs-base);
  font-weight: 600;
  letter-spacing: 0;
}
}