:root {
  --ink: #102c33;
  --ink-soft: #425f65;
  --ink-faint: #5f767a;
  --paper: #f7faf9;
  --paper-blue: #edf3f4;
  --surface: #ffffff;
  --line: #cfdddf;
  --line-strong: #718b90;
  --teal: #0b6168;
  --teal-dark: #084d53;
  --teal-pale: #d9eceb;
  --coral: #e86f51;
  --coral-pale: #fce7df;
  --danger: #a53b30;
  --font-display: "Avenir Next Condensed", "Arial Narrow", "Liberation Sans Narrow", sans-serif;
  --font-ui: "Avenir Next", Avenir, "Segoe UI", Helvetica, Arial, sans-serif;
  --font-reading: Charter, "Bitstream Charter", "Iowan Old Style", Cambria, Georgia, serif;
  --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  --content: 1160px;
  --reading: 700px;
  --radius: 10px;
  --shadow: 0 22px 70px rgba(16, 44, 51, 0.10);
}

*, *::before, *::after { box-sizing: border-box; }
html { overflow-x: hidden; scroll-behavior: smooth; scroll-padding-top: 90px; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-ui);
  font-size: 17px;
  line-height: 1.65;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}
body::before {
  content: "";
  position: fixed;
  inset: 0 auto 0 0;
  width: 5px;
  background: var(--teal);
  z-index: 200;
}
img { display: block; max-width: 100%; height: auto; }
button, input, select, textarea { font: inherit; }
button, [type="submit"] { cursor: pointer; }
a { color: var(--teal); text-underline-offset: .18em; text-decoration-thickness: 1px; }
a:hover { color: var(--teal-dark); }
p { margin: 0 0 1.25em; }
strong { font-weight: 700; }
small { font-size: .82rem; }
[hidden] { display: none !important; }

h1, h2, h3, h4 {
  color: var(--ink);
  font-family: var(--font-display);
  font-stretch: condensed;
  line-height: 1.08;
  margin: 0 0 .65em;
}
h1 { font-size: clamp(2.75rem, 6.5vw, 5.7rem); letter-spacing: -.045em; }
h2 { font-size: clamp(2.1rem, 4vw, 3.5rem); letter-spacing: -.035em; }
h3 { font-size: clamp(1.35rem, 2vw, 1.75rem); letter-spacing: -.02em; }
h4 { font-size: 1.15rem; }

:focus-visible {
  outline: 3px solid var(--coral);
  outline-offset: 4px;
}
.skip-link {
  position: fixed;
  left: 1rem;
  top: 1rem;
  z-index: 1000;
  padding: .75rem 1rem;
  background: var(--ink);
  color: #fff;
  transform: translateY(-180%);
}
.skip-link:focus { transform: none; }
.container { width: min(100% - 48px, var(--content)); margin-inline: auto; }
.site-content { min-height: 60vh; padding: 72px 0 110px; }

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(247, 250, 249, .94);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(14px);
}
.header-container {
  width: min(100% - 48px, var(--content));
  min-height: 70px;
  margin-inline: auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
}
.site-logo {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-family: var(--font-display);
  font-size: 1.12rem;
  font-weight: 800;
  letter-spacing: -.015em;
  text-decoration: none;
  white-space: nowrap;
}
.token-mark { display: inline-flex; align-items: flex-end; gap: 2px; height: 25px; }
.token-mark i { display: block; width: 7px; border-radius: 2px 2px 1px 1px; background: var(--teal); }
.token-mark i:nth-child(1) { height: 12px; }
.token-mark i:nth-child(2) { height: 18px; background: #62aaa5; }
.token-mark i:nth-child(3) { height: 25px; background: var(--coral); }
.site-nav { display: flex; align-items: center; gap: 2px; font-size: .89rem; font-weight: 650; }
.site-nav a { padding: 10px 11px; color: var(--ink-soft); text-decoration: none; border-radius: 7px; }
.site-nav a:hover, .site-nav a[aria-current="page"] { color: var(--teal); background: var(--teal-pale); }
.site-nav .account-link { margin-left: 7px; border: 1px solid var(--line-strong); color: var(--ink); }
.language-switcher { position: relative; margin-left: 5px; }
.language-switcher summary { min-width: 40px; padding: 9px 10px; border: 1px solid var(--line); border-radius: 7px; color: var(--ink-soft); cursor: pointer; list-style: none; text-align: center; }
.language-switcher summary::-webkit-details-marker { display: none; }
.language-switcher summary::after { content: "▾"; margin-left: 5px; font-size: .7em; }
.language-switcher[open] summary, .language-switcher summary:hover { border-color: var(--line-strong); color: var(--teal); background: var(--teal-pale); }
.language-switcher ul { position: absolute; top: calc(100% + 8px); right: 0; min-width: 92px; margin: 0; padding: 6px; border: 1px solid var(--line); border-radius: 8px; background: var(--surface); box-shadow: 0 12px 30px rgba(16,44,51,.12); list-style: none; }
.language-switcher li { margin: 0; }
.language-switcher a { display: block; text-align: center; }
.menu-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  border: 1px solid var(--line);
  border-radius: 7px;
  background: var(--surface);
  color: var(--ink);
  padding: 8px 11px;
  font-size: .85rem;
  font-weight: 700;
}
.menu-toggle i, .menu-toggle i::before, .menu-toggle i::after { display: block; width: 18px; height: 2px; background: currentColor; content: ""; }
.menu-toggle i { position: relative; }
.menu-toggle i::before { position: absolute; top: -5px; }
.menu-toggle i::after { position: absolute; top: 5px; }

/* Book navigation lives below the platform navigation. */
.book-subnav {
  position: sticky;
  top: 70px;
  z-index: 90;
  border-bottom: 1px solid var(--line);
  background: var(--surface);
}
.book-subnav-inner {
  width: min(100% - 48px, var(--content));
  min-height: 52px;
  margin-inline: auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
}
.book-subnav-title {
  overflow: hidden;
  color: var(--ink);
  font-family: var(--font-reading);
  font-size: .88rem;
  font-weight: 700;
  text-decoration: none;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.book-subnav-links { display: flex; align-items: stretch; align-self: stretch; }
.book-subnav-links a {
  display: flex;
  align-items: center;
  padding: 0 12px;
  border-bottom: 2px solid transparent;
  color: var(--ink-soft);
  font-size: .78rem;
  font-weight: 700;
  text-decoration: none;
}
.book-subnav-links a:hover,
.book-subnav-links a[aria-current="page"] { border-bottom-color: var(--coral); color: var(--ink); }
.book-navigation-more { position: relative; flex: 0 0 auto; }
.book-navigation-more summary {
  min-height: 52px;
  display: flex;
  align-items: center;
  padding: 0 12px;
  border-bottom: 2px solid transparent;
  color: var(--ink-soft);
  font-size: .78rem;
  font-weight: 700;
  cursor: pointer;
}
.book-navigation-more[data-current] summary,
.book-navigation-more[open] summary,
.book-navigation-more summary:hover { border-bottom-color: var(--coral); color: var(--ink); }
.book-navigation-more summary:focus-visible { outline-offset: -4px; }
.book-navigation-more-links {
  position: absolute;
  top: calc(100% + 1px);
  right: 0;
  z-index: 95;
  min-width: 175px;
  padding: 6px;
  border: 1px solid var(--line);
  border-radius: 0 0 7px 7px;
  background: var(--surface);
  box-shadow: 0 12px 30px rgba(16,44,51,.12);
}
.book-navigation-more-links a {
  min-height: 42px;
  padding: 8px 10px;
  border: 0;
  border-radius: 5px;
}
.book-navigation-more-links a:hover,
.book-navigation-more-links a[aria-current="page"] { border: 0; background: var(--teal-pale); color: var(--teal-dark); }

/* Platform home: the large coordinate-like name is the visual signature. */
.platform-hero {
  position: relative;
  min-height: 430px;
  overflow: hidden;
  border-bottom: 1px solid var(--line);
  background: var(--paper-blue);
}
.platform-hero::after {
  content: "2718";
  position: absolute;
  right: max(-.04em, calc((100vw - var(--content)) / 2));
  bottom: -.27em;
  color: transparent;
  font-family: var(--font-display);
  font-size: clamp(13rem, 30vw, 27rem);
  font-weight: 900;
  letter-spacing: -.08em;
  line-height: .78;
  -webkit-text-stroke: 1px rgba(11, 97, 104, .16);
  pointer-events: none;
}
.platform-hero-inner {
  position: relative;
  z-index: 1;
  width: min(100% - 48px, var(--content));
  margin-inline: auto;
  padding: 100px 0 96px;
}
.platform-hero h1 { margin-bottom: 22px; font-size: clamp(4.5rem, 11vw, 9rem); }
.platform-hero-inner > p:last-child {
  max-width: 660px;
  color: var(--ink-soft);
  font-family: var(--font-reading);
  font-size: clamp(1.22rem, 2.4vw, 1.6rem);
  line-height: 1.55;
}

/* Hero: the token/prediction panel is the visual signature. */
.hero { position: relative; overflow: hidden; border-bottom: 1px solid var(--line); background: var(--paper-blue); }
.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: linear-gradient(rgba(11, 97, 104, .06) 1px, transparent 1px), linear-gradient(90deg, rgba(11, 97, 104, .06) 1px, transparent 1px);
  background-size: 42px 42px;
  mask-image: linear-gradient(90deg, #000, transparent 75%);
  pointer-events: none;
}
.hero-layout {
  position: relative;
  width: min(100% - 48px, var(--content));
  min-height: 620px;
  margin-inline: auto;
  display: grid;
  grid-template-columns: minmax(0, 1.3fr) minmax(390px, .7fr);
  gap: clamp(42px, 5vw, 72px);
  align-items: center;
  padding: 82px 0 90px;
}
.book-hero .hero-layout {
  grid-template-columns: minmax(0, 1fr) minmax(340px, 420px);
  min-height: 560px;
  padding-block: 70px 78px;
}
.book-hero .hero-copy { max-width: 700px; }
.book-hero .hero-copy h1 { overflow-wrap: anywhere; }
.book-edition-line { margin: -5px 0 24px; color: var(--ink-faint); font-size: .78rem; font-weight: 650; }
.hero-copy, .next-token-demo { min-width: 0; }
.eyebrow {
  color: var(--teal);
  font-family: var(--font-mono);
  font-size: .75rem;
  font-weight: 700;
  letter-spacing: .09em;
  line-height: 1.4;
  margin: 0 0 18px;
  text-transform: uppercase;
}
.hero h1 { max-width: 760px; margin-bottom: 24px; font-size: clamp(3.6rem, 5.4vw, 4.9rem); }
.hero h1 span { display: block; color: var(--teal); }
.hero-subtitle { max-width: 680px; color: var(--ink-soft); font-family: var(--font-reading); font-size: clamp(1.14rem, 2vw, 1.34rem); line-height: 1.62; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin: 32px 0 15px; }
.btn {
  min-height: 48px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  padding: 11px 20px;
  border: 1px solid transparent;
  border-radius: 7px;
  font-family: var(--font-ui);
  font-size: .93rem;
  font-weight: 750;
  line-height: 1.2;
  text-decoration: none;
  transition: transform .18s ease, background .18s ease, border-color .18s ease;
}
.btn-primary, button[type="submit"] { border-color: var(--teal); background: var(--teal); color: #fff; }
.btn-primary:hover, button[type="submit"]:hover { background: var(--teal-dark); color: #fff; transform: translateY(-1px); }
.btn-secondary, .btn-outline { border-color: var(--line-strong); background: rgba(255,255,255,.55); color: var(--ink); }
.btn-secondary:hover, .btn-outline:hover { border-color: var(--teal); background: var(--surface); color: var(--teal); }
.text-link { font-weight: 750; text-decoration: none; border-bottom: 1px solid currentColor; }

.next-token-demo {
  position: relative;
  margin: 0;
  padding: 25px;
  border: 1px solid var(--line-strong);
  border-radius: 12px;
  background: var(--surface);
  box-shadow: var(--shadow);
  transform: none;
}
.next-token-demo::before { content: ""; position: absolute; inset: 10px -11px -11px 10px; border: 1px solid var(--line); border-radius: 12px; z-index: -1; background: #dfe9ea; }
.next-token-demo figcaption { display: flex; align-items: baseline; justify-content: space-between; gap: 15px; padding-bottom: 18px; border-bottom: 1px solid var(--line); }
.next-token-demo figcaption span { font-family: var(--font-display); font-size: 1.2rem; font-weight: 800; }
.next-token-demo figcaption small { color: var(--ink-faint); font-family: var(--font-mono); }
.prompt-line { display: flex; flex-wrap: wrap; gap: 5px; align-items: center; margin: 28px 0; }
.prompt-line span, .prompt-line b { padding: 5px 8px; border: 1px solid #b6ccce; border-radius: 5px; background: var(--paper-blue); font-family: var(--font-mono); font-size: .78rem; font-weight: 500; }
.prompt-line span:nth-child(2), .prompt-line span:nth-child(4) { background: var(--coral-pale); border-color: #f1baa9; }
.prompt-line b { color: var(--teal); background: var(--teal-pale); }
.prediction-list { display: grid; gap: 11px; }
.prediction-list div { display: grid; grid-template-columns: 52px 1fr 44px; gap: 10px; align-items: center; font-family: var(--font-mono); font-size: .72rem; }
.prediction-list i { height: 9px; border-radius: 10px; background: var(--paper-blue); overflow: hidden; }
.prediction-list i::after { content: ""; display: block; width: var(--probability); height: 100%; border-radius: inherit; background: var(--teal); }
.prediction-list div:nth-child(2) i::after { background: #62aaa5; }
.prediction-list div:nth-child(3) i::after { background: var(--coral); }
.prediction-list strong { text-align: right; }
.next-token-demo > p { margin: 25px 0 0; padding-top: 18px; border-top: 1px solid var(--line); color: var(--ink-soft); font-family: var(--font-reading); font-size: .96rem; line-height: 1.55; }

/* Home sections */
.catalog-section { padding: 16px 0 30px; }
.catalog-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 30px;
  margin-bottom: 34px;
  padding-bottom: 20px;
  border-bottom: 2px solid var(--ink);
}
.catalog-heading .eyebrow { margin-bottom: 9px; }
.catalog-heading h2 { margin: 0; }
.content-cards { display: grid; gap: 22px; }
.content-card {
  position: relative;
  display: grid;
  grid-template-columns: minmax(220px, .8fr) minmax(300px, 1.2fr) auto;
  gap: clamp(24px, 5vw, 70px);
  align-items: start;
  padding: clamp(26px, 4vw, 46px);
  border: 1px solid var(--line);
  border-left: 5px solid var(--teal);
  background: var(--surface);
}
.content-card-type {
  grid-column: 1 / -1;
  display: flex;
  justify-content: space-between;
  padding-bottom: 13px;
  border-bottom: 1px solid var(--line);
  color: var(--ink-faint);
  font-family: var(--font-mono);
  font-size: .7rem;
  font-weight: 700;
  letter-spacing: .08em;
  text-transform: uppercase;
}
.content-card h2,
.content-card h3 { margin: 0; font-size: clamp(2rem, 4vw, 3.1rem); }
.content-card h2 a,
.content-card h3 a { color: var(--ink); text-decoration: none; }
.content-card h2 a:hover,
.content-card h3 a:hover { color: var(--teal); }
.content-card p { margin: 0; color: var(--ink-soft); }
.content-card .content-card-subtitle {
  color: var(--ink);
  font-family: var(--font-reading);
  font-size: 1.12rem;
  line-height: 1.55;
}
.content-card-link {
  align-self: end;
  white-space: nowrap;
  font-size: .82rem;
  font-weight: 750;
  text-decoration: none;
}
.editorial-section { display: grid; grid-template-columns: .8fr 1.2fr; gap: clamp(50px, 9vw, 130px); padding: 20px 0 110px; }
.section-heading h2 { max-width: 520px; }
.section-copy { max-width: 650px; padding-top: 35px; }
.lede { color: var(--ink); font-family: var(--font-reading); font-size: clamp(1.2rem, 2.2vw, 1.55rem); line-height: 1.55; }
.section-copy > p:not(.lede) { color: var(--ink-soft); }
.learning-map { display: block; border-top: 1px solid var(--line); }
.learning-map .section-heading { display: flex; justify-content: space-between; align-items: end; gap: 40px; margin-bottom: 42px; }
.learning-map .section-heading h2 { margin: 0; }
.part-cards { list-style: none; display: grid; grid-template-columns: repeat(3, 1fr); margin: 0 0 35px; padding: 0; border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; background: var(--surface); }
.part-cards li { min-height: 300px; display: flex; flex-direction: column; justify-content: space-between; gap: 35px; padding: 30px; border-right: 1px solid var(--line); }
.part-cards li:last-child { border-right: 0; }
.part-index { color: var(--coral); font-family: var(--font-mono); font-size: .85rem; font-weight: 800; }
.part-index::before { content: "Teil "; color: var(--ink-faint); font-weight: 500; }
.part-cards h3 { margin-bottom: 12px; }
.part-cards p { margin: 0; color: var(--ink-soft); font-size: .93rem; }

/* Newsletter */
.newsletter-card { position: relative; margin: 25px 0 0; padding: clamp(30px, 6vw, 64px); overflow: hidden; border: 1px solid #9bb9bb; border-radius: 12px; background: var(--teal-pale); }
.newsletter-card::after { content: "↗"; position: absolute; right: -20px; top: -65px; color: rgba(11,97,104,.08); font-family: var(--font-display); font-size: 16rem; font-weight: 900; line-height: 1; }
.newsletter-card h2, .newsletter-card > p, .newsletter-card form, .newsletter-card small { position: relative; z-index: 1; max-width: 760px; }
.newsletter-card > p:not(.eyebrow) { color: var(--ink-soft); font-family: var(--font-reading); font-size: 1.12rem; }
.newsletter-form label { display: block; margin-bottom: 7px; font-size: .8rem; font-weight: 750; }
.newsletter-fields { display: flex; gap: 9px; }
.newsletter-fields input { flex: 1 1 350px; }
.newsletter-card small { display: block; margin-top: 12px; color: var(--ink-soft); }

/* Shared page structures */
.page-intro, .page-header { max-width: 820px; margin: 0 0 70px; padding: 18px 0 0; text-align: left; }
.page-intro.compact { margin-bottom: 45px; }
.page-intro h1, .page-header h1 { font-size: clamp(2.7rem, 6vw, 4.8rem); }
.page-intro .lede, .page-header p { color: var(--ink-soft); }
.prose { max-width: var(--reading); margin-inline: auto; color: var(--ink-soft); font-family: var(--font-reading); font-size: 1.08rem; line-height: 1.8; }
.prose h2, .prose h3 { margin-top: 2.2em; font-family: var(--font-display); }
.prose h2 { font-size: 2rem; }
.prose h3 { font-size: 1.4rem; }
.prose ul, .prose ol { padding-left: 1.35em; }
.prose li { padding-left: .25em; margin-bottom: .5em; }
.prose li::marker { color: var(--coral); }
blockquote { margin: 2em 0; padding: 24px 28px; border-left: 4px solid var(--coral); background: var(--coral-pale); color: var(--ink); font-family: var(--font-reading); font-style: italic; }
.empty-state { max-width: 720px; margin: 35px auto 70px; padding: 45px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--surface); text-align: center; }
.empty-state h1 { font-size: clamp(2.4rem, 5vw, 4rem); }

/* Inputs and application pages */
label { display: block; margin-bottom: 7px; color: var(--ink); font-size: .84rem; font-weight: 750; }
input, select, textarea {
  width: 100%;
  min-height: 48px;
  padding: 11px 13px;
  border: 1px solid var(--line-strong);
  border-radius: 6px;
  background: var(--surface);
  color: var(--ink);
}
textarea { resize: vertical; }
input:focus, select:focus, textarea:focus { border-color: var(--teal); box-shadow: 0 0 0 3px var(--teal-pale); outline: 0; }
button[type="submit"] { min-height: 48px; padding: 11px 20px; border-radius: 7px; font-weight: 750; }
.field { margin-bottom: 18px; }
.field-error, .errorlist { color: var(--danger); font-size: .85rem; }
.form-note { color: var(--ink-faint); font-size: .86rem; }
.auth-card { max-width: 560px; margin: 25px auto 80px; padding: clamp(30px, 6vw, 55px); border: 1px solid var(--line); border-radius: 12px; background: var(--surface); box-shadow: var(--shadow); }
.auth-card h1 { font-size: clamp(2.4rem, 5vw, 3.8rem); }
.auth-card form button { width: 100%; }
.search-form { max-width: 760px; margin-bottom: 55px; }
.search-form > div { display: flex; gap: 9px; }
.search-form button { min-width: 120px; }
.search-results, .feedback-list, .account-list { list-style: none; padding: 0; }
.search-results li, .feedback-list li { border-top: 1px solid var(--line); }
.search-results a, .feedback-list a { display: block; padding: 25px 5px; color: var(--ink); text-decoration: none; }
.search-results a:hover h3, .feedback-list a:hover strong { color: var(--teal); }
.search-results h3 { margin-bottom: 8px; }
.search-results p, .feedback-list p { color: var(--ink-soft); margin: 0; }
.dashboard-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 20px; }
.dashboard-grid > section { padding: 26px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--surface); }
.dashboard-grid h2, .dashboard-grid h3 { font-size: 1.55rem; }
.dashboard-grid .newsletter-card { margin: 15px 0 0; padding: 18px; }
.dashboard-grid .newsletter-card h2 { font-size: 1.35rem; }
.dashboard-grid .newsletter-fields { display: grid; }
.reader-content { margin-bottom: 70px; }
.reader-content-header { margin-bottom: 22px; padding-bottom: 16px; border-bottom: 2px solid var(--ink); }
.reader-content-header h2 { margin-bottom: 8px; font-size: clamp(2rem, 4vw, 3rem); }
.reader-content-header p { max-width: 760px; margin: 0; color: var(--ink-soft); font-family: var(--font-reading); }
.account-list { margin: 0; }
.account-list li { border-top: 1px solid var(--line); }
.account-list a { display: grid; gap: 3px; padding: 13px 0; color: var(--ink); text-decoration: none; }
.account-list span { color: var(--ink-faint); font-size: .8rem; }
.danger-zone { max-width: 700px; margin-top: 55px; padding: 28px; border: 1px solid #dfaaa2; background: #fff6f3; }
.danger-zone button { border-color: var(--danger); background: var(--danger); }
.status { display: inline-block; margin-right: 10px; padding: 3px 7px; border-radius: 4px; background: var(--paper-blue); color: var(--ink-soft); font-family: var(--font-mono); font-size: .68rem; text-transform: uppercase; }
.feedback-detail { max-width: var(--reading); margin-inline: auto; }
.feedback-detail h1 { font-size: clamp(2.6rem, 5vw, 4rem); }
.feedback-detail section { padding-top: 20px; border-top: 1px solid var(--line); }
.editor-reply { padding: 25px !important; border: 1px solid #9fc6c3 !important; background: var(--teal-pale); }

/* Book contents */
.contents-heading { max-width: 900px; margin-bottom: 42px; padding-bottom: 18px; border-bottom: 2px solid var(--ink); }
.contents-heading .eyebrow { margin-bottom: 9px; }
.contents-heading h2 { margin: 0; }
.book-contents { max-width: 900px; }
.contents-part { margin-bottom: 70px; }
.contents-part > h2 { padding-bottom: 15px; border-bottom: 2px solid var(--ink); font-size: clamp(1.7rem, 3vw, 2.45rem); }
.chapter-list { list-style: none; counter-reset: chapter; margin: 0; padding: 0; }
.chapter-list li { counter-increment: chapter; border-bottom: 1px solid var(--line); }
.chapter-list a { display: grid; grid-template-columns: 1fr auto; gap: 24px; align-items: center; padding: 18px 8px; color: var(--ink); text-decoration: none; }
.chapter-list a::before { content: counter(chapter, decimal-leading-zero); grid-row: 1; color: var(--ink-faint); font-family: var(--font-mono); font-size: .72rem; }
.chapter-list a span:first-child { grid-column: 1; font-family: var(--font-reading); font-size: 1.08rem; }
.chapter-list a span:last-child { grid-column: 2; grid-row: 1 / span 2; color: var(--coral); }
.chapter-list a:hover { padding-left: 16px; background: var(--paper-blue); }

/* Reading view */
.reader-shell { display: grid; grid-template-columns: 245px minmax(0, 1fr); gap: clamp(45px, 7vw, 90px); align-items: start; }
.reader-rail { position: sticky; top: 95px; max-height: calc(100vh - 125px); overflow: auto; padding-right: 18px; scrollbar-width: thin; }
.back-to-contents { display: block; margin-bottom: 18px; color: var(--teal); font-size: .78rem; font-weight: 750; text-decoration: none; }
.reader-rail ol { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--line); }
.reader-rail li { border-bottom: 1px solid var(--line); }
.reader-rail a { display: block; padding: 9px 7px; color: var(--ink-faint); font-family: var(--font-reading); font-size: .78rem; line-height: 1.3; text-decoration: none; }
.reader-rail li[aria-current="page"] a { border-left: 3px solid var(--coral); color: var(--ink); font-weight: 700; padding-left: 10px; }
.book-page { min-width: 0; max-width: 780px; }
.reading-progress { position: sticky; top: 70px; z-index: 50; height: 4px; margin-bottom: 55px; background: var(--line); }
.reading-progress span { display: block; width: 0; height: 100%; background: var(--coral); transition: width .15s linear; }
.chapter-header { max-width: var(--reading); margin: 0 auto 55px; padding-bottom: 35px; border-bottom: 1px solid var(--line); }
.chapter-header h1 { font-size: clamp(2.8rem, 7vw, 5rem); }
.chapter-body { max-width: var(--reading); margin-inline: auto; color: #263f45; font-family: var(--font-reading); font-size: clamp(1.08rem, 1.4vw, 1.2rem); line-height: 1.82; }
.chapter-body h2, .chapter-body h3, .chapter-body h4 { scroll-margin-top: 95px; margin-top: 2.4em; font-family: var(--font-display); }
.chapter-body h2 { font-size: clamp(2rem, 4vw, 2.7rem); }
.chapter-body h3 { font-size: clamp(1.55rem, 3vw, 2rem); }
.chapter-body p { margin-bottom: 1.45em; }
.chapter-body a { text-decoration: underline; }
.chapter-body img { margin: 35px auto; border: 1px solid var(--line); border-radius: 7px; background: var(--surface); }
.chapter-body figure { margin: 35px 0; }
.chapter-body figcaption { color: var(--ink-faint); font-family: var(--font-ui); font-size: .78rem; text-align: center; }
.chapter-body pre { max-width: 100%; padding: 20px; overflow: auto; border: 1px solid var(--line); background: var(--ink); color: #e5f0f1; font-family: var(--font-mono); font-size: .82rem; line-height: 1.55; }
.chapter-body code { padding: .08em .28em; background: var(--paper-blue); color: var(--teal-dark); font-family: var(--font-mono); font-size: .84em; }
.chapter-body pre code { padding: 0; background: transparent; color: inherit; }
.chapter-body table { width: 100%; display: block; margin: 30px 0; overflow-x: auto; border-collapse: collapse; font-family: var(--font-ui); font-size: .85rem; }
.chapter-body th, .chapter-body td { padding: 10px 12px; border: 1px solid var(--line); text-align: left; }
.chapter-body th { background: var(--paper-blue); }
.chapter-body hr { margin: 50px 0; border: 0; border-top: 1px solid var(--line); }
.chapter-body [data-reader-block] { scroll-margin-top: 105px; }
.reader-actions { max-width: var(--reading); display: flex; flex-wrap: wrap; gap: 10px; align-items: center; margin: 60px auto 35px; padding: 18px 0; border-block: 1px solid var(--line); }
.reader-tool { min-height: 44px; display: inline-flex; align-items: center; justify-content: center; padding: 9px 12px; border: 1px solid var(--line-strong); border-radius: 6px; background: var(--surface); color: var(--ink); font-size: .8rem; font-weight: 700; text-decoration: none; }
.reader-tool:hover { border-color: var(--teal); color: var(--teal); }
.reader-status { color: var(--teal); font-size: .78rem; }
.chapter-bookmarks { max-width: var(--reading); margin: 30px auto; padding: 22px; background: var(--paper-blue); }
.chapter-bookmarks h2 { font-size: 1.5rem; }
.selection-feedback { position: absolute; z-index: 80; width: auto; min-height: 0; padding: 8px 11px; border: 0; border-radius: 5px; background: var(--ink); color: #fff; font-size: .75rem; }
.feedback-dialog { width: min(92vw, 620px); max-height: 88vh; padding: 32px; overflow: auto; border: 1px solid var(--line-strong); border-radius: 12px; background: var(--surface); color: var(--ink); box-shadow: var(--shadow); }
.feedback-dialog::backdrop { background: rgba(16, 44, 51, .64); backdrop-filter: blur(3px); }
.feedback-dialog h2 { font-size: 2.4rem; }
.feedback-dialog label { margin-top: 18px; }
.feedback-dialog .consent-field { display: grid; grid-template-columns: auto 1fr; gap: 10px; align-items: start; color: var(--ink-soft); font-size: .86rem; font-weight: 500; line-height: 1.5; }
.feedback-dialog .consent-field input { width: 18px; height: 18px; margin-top: 2px; }
.feedback-dialog blockquote { max-height: 130px; overflow: auto; font-size: .9rem; }
.dialog-close-form { position: absolute; right: 16px; top: 12px; }
.dialog-close-form button { border: 0; background: transparent; color: var(--ink-soft); font-size: 1.8rem; }
.chapter-pagination { max-width: var(--reading); display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: 12px; margin: 55px auto; }
.chapter-pagination a { min-height: 100px; display: flex; flex-direction: column; justify-content: center; padding: 18px; border: 1px solid var(--line); border-radius: 7px; background: var(--surface); color: var(--ink); text-decoration: none; }
.chapter-pagination a:last-child { text-align: right; grid-column: 2; }
.chapter-pagination small { color: var(--ink-faint); font-family: var(--font-mono); text-transform: uppercase; }
.chapter-pagination span { font-family: var(--font-reading); }
.book-page > .newsletter-card { max-width: var(--reading); margin-inline: auto; }

/* Glossary */
.glossary-intro { max-width: var(--reading); margin-left: calc(245px + clamp(45px, 7vw, 90px)); }
.glossary-introduction { color: var(--ink-soft); font-family: var(--font-reading); font-size: 1.08rem; }
.glossary-search { max-width: var(--reading); margin: 0 0 45px calc(245px + clamp(45px, 7vw, 90px)); }
.glossary-search input { font-family: var(--font-reading); font-size: 1.05rem; }
.glossary-count { margin: 8px 0 0; color: var(--ink-faint); font-size: .8rem; }
.glossary-layout { display: grid; grid-template-columns: 245px minmax(0, 1fr); gap: clamp(45px, 7vw, 90px); align-items: start; }
.glossary-rail { position: sticky; top: 95px; max-height: calc(100vh - 125px); overflow: auto; padding-right: 18px; scrollbar-width: thin; }
.glossary-rail ol, .glossary-mobile-index ol { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--line); }
.glossary-rail li, .glossary-mobile-index li { border-bottom: 1px solid var(--line); }
.glossary-rail a, .glossary-mobile-index a { min-height: 44px; display: flex; align-items: center; padding: 8px 7px; color: var(--ink-faint); font-family: var(--font-reading); font-size: .78rem; line-height: 1.3; text-decoration: none; }
.glossary-rail a:hover, .glossary-mobile-index a:hover { color: var(--teal); }
.glossary-terms { min-width: 0; max-width: var(--reading); }
.glossary-term { scroll-margin-top: 95px; padding: 0 0 36px; margin-bottom: 36px; border-bottom: 1px solid var(--line); }
.glossary-term h2 { margin-bottom: 12px; font-size: clamp(1.6rem, 3vw, 2.1rem); }
.glossary-term div { color: #263f45; font-family: var(--font-reading); font-size: 1.08rem; line-height: 1.75; }
.glossary-term div > :last-child { margin-bottom: 0; }
.glossary-empty { padding: 28px; border: 1px solid var(--line); background: var(--surface); color: var(--ink-soft); }
.glossary-mobile-index { display: none; }

/* Footer */
.site-footer { padding: 55px 0; border-top: 1px solid var(--line); background: var(--paper-blue); }
.footer-container { width: min(100% - 48px, var(--content)); margin-inline: auto; display: grid; grid-template-columns: 1fr auto; gap: 30px; align-items: start; }
.footer-links { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 8px 24px; }
.footer-links a { color: var(--ink-soft); font-size: .82rem; }
.footer-copy { margin: 0; color: var(--ink-faint); font-size: .78rem; }
.scroll-top-btn { position: fixed; right: 24px; bottom: 24px; z-index: 90; width: 44px; height: 44px; border: 1px solid var(--line-strong); border-radius: 50%; background: var(--surface); color: var(--ink); box-shadow: 0 8px 25px rgba(16,44,51,.13); }

@media (max-width: 980px) {
  .menu-toggle { display: inline-flex; }
  .site-nav { position: absolute; top: 70px; left: 0; right: 0; display: none; padding: 14px 24px 22px; border-bottom: 1px solid var(--line); background: var(--paper); box-shadow: 0 15px 30px rgba(16,44,51,.08); }
  .site-nav.is-open { display: grid; }
  .site-nav a { padding: 11px; }
  .site-nav .account-link { margin: 5px 0 0; text-align: center; }
  .language-switcher { margin: 5px 0; }
  .language-switcher summary { text-align: left; }
  .language-switcher ul { position: static; margin-top: 5px; box-shadow: none; }
  .book-subnav-inner { position: relative; display: block; width: 100%; }
  .book-subnav-title { display: none; }
  .book-subnav-links { flex-wrap: wrap; overflow: visible; padding-inline: 24px; }
  .book-subnav-links a { min-height: 50px; flex: 0 0 auto; }
  .book-navigation-more summary { min-height: 50px; }
  .hero-layout, .book-hero .hero-layout { grid-template-columns: 1fr; min-height: auto; }
  .next-token-demo { width: min(100%, 560px); transform: none; }
  .editorial-section { grid-template-columns: 1fr; gap: 12px; }
  .section-copy { padding-top: 0; }
  .part-cards { grid-template-columns: 1fr; }
  .content-card { grid-template-columns: 1fr; gap: 18px; }
  .content-card-type { grid-column: 1; }
  .content-card-link { margin-top: 8px; }
  .part-cards li { min-height: 0; display: grid; grid-template-columns: 55px 1fr; gap: 10px; border-right: 0; border-bottom: 1px solid var(--line); }
  .part-cards li:last-child { border-bottom: 0; }
  .reader-shell { grid-template-columns: 1fr; }
  .reader-rail { position: static; max-height: none; padding: 0; }
  .reader-rail ol { display: none; }
  .reading-progress { top: 70px; }
  .dashboard-grid { grid-template-columns: 1fr; }
  .glossary-intro, .glossary-search { margin-left: 0; }
  .glossary-layout { grid-template-columns: 1fr; }
  .glossary-rail { display: none; }
  .glossary-mobile-index { display: block; max-width: var(--reading); margin-bottom: 38px; border-block: 1px solid var(--line); }
  .glossary-mobile-index summary { min-height: 48px; display: flex; align-items: center; justify-content: space-between; cursor: pointer; color: var(--ink); font-weight: 700; }
  .glossary-mobile-index summary::after { content: "+"; color: var(--teal); font-size: 1.3rem; }
  .glossary-mobile-index[open] summary::after { content: "−"; }
  .glossary-mobile-index nav { max-height: 45vh; overflow: auto; padding-bottom: 12px; }
}

@media (max-width: 680px) {
  body { font-size: 16px; }
  body::before { width: 3px; }
  .container, .header-container, .hero-layout, .footer-container { width: min(100% - 30px, var(--content)); }
  .header-container { min-height: 62px; }
  .site-logo { font-size: 1rem; }
  .site-nav { top: 62px; }
  .book-subnav { top: 62px; }
  .book-subnav-links { padding-inline: 15px; }
  .book-subnav-links > a, .book-navigation-more summary { min-height: 44px; padding-inline: 8px; }
  .book-navigation-more-links { right: 15px; max-width: calc(100vw - 30px); }
  .site-content { padding: 48px 0 75px; }
  .platform-hero { min-height: 350px; }
  .platform-hero-inner { width: min(100% - 30px, var(--content)); padding: 72px 0 68px; }
  .platform-hero h1 { font-size: clamp(3.7rem, 22vw, 5.4rem); }
  .platform-hero::after { right: -.1em; font-size: 16rem; }
  .hero-layout { gap: 45px; padding: 58px 0 72px; }
  .hero h1 { font-size: clamp(2.75rem, 12.5vw, 3.25rem); }
  .hero-actions { align-items: stretch; flex-direction: column; }
  .hero-actions .btn { width: 100%; }
  .next-token-demo { width: calc(100% - 8px); padding: 19px; }
  .next-token-demo figcaption { display: grid; }
  .editorial-section { padding-bottom: 80px; }
  .learning-map .section-heading { display: block; }
  .part-cards li { padding: 23px; }
  .newsletter-card { padding: 27px 20px; }
  .newsletter-fields, .search-form > div { display: grid; }
  .newsletter-fields button, .search-form button { width: 100%; }
  .page-intro, .page-header { margin-bottom: 45px; }
  .chapter-list a { padding-inline: 3px; }
  .book-page { max-width: 100%; }
  .reading-progress { top: 62px; margin-bottom: 38px; }
  .chapter-header { margin-bottom: 38px; }
  .chapter-body { line-height: 1.72; }
  .chapter-body h2 { margin-top: 2em; }
  .reader-actions { align-items: stretch; flex-direction: column; }
  .reader-tool { text-align: center; }
  .chapter-pagination { grid-template-columns: 1fr; }
  .chapter-pagination a:last-child { grid-column: 1; text-align: left; }
  .feedback-dialog { padding: 27px 20px; }
  .footer-container { grid-template-columns: 1fr; }
  .footer-links { justify-content: flex-start; }
  .footer-copy { grid-column: 1; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: .01ms !important; animation-duration: .01ms !important; animation-iteration-count: 1 !important; }
}

@media print {
  .site-header, .site-footer, .reader-rail, .reading-progress, .reader-actions, .chapter-pagination, .newsletter-card, .scroll-top-btn { display: none !important; }
  body { background: #fff; color: #000; }
  body::before { display: none; }
  .site-content { padding: 0; }
  .container, .book-page, .chapter-body { width: 100%; max-width: none; }
  .chapter-body { font-size: 11pt; }
}