:root {
  color-scheme: dark;
  --obsidian: #0b0c10;
  --panel: #12151a;
  --panel-deep: #0e1116;
  --green: #34d399;
  --green-pale: #a7f3d0;
  --ash: #9ca3af;
  --paper: #f2f5f3;
  --rule: #30363d;
  --measure: 72ch;
}

* {
  box-sizing: border-box;
}

html {
  background: var(--obsidian);
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--obsidian);
  color: var(--paper);
  font-family: Georgia, Cambria, "Times New Roman", Times, serif;
  font-size: 18px;
  line-height: 1.68;
}

a {
  color: var(--green-pale);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.22em;
}

a:hover,
a:focus-visible {
  color: #ffffff;
}

:focus-visible {
  outline: 3px solid var(--green);
  outline-offset: 4px;
}

.page-shell {
  width: min(1180px, calc(100% - 96px));
  margin: 0 auto;
}

.breadcrumb-trail {
  display: flex;
  align-items: center;
  min-height: 72px;
  border-bottom: 1px solid var(--rule);
  color: var(--ash);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 16px;
  letter-spacing: 0.02em;
}

.breadcrumb-trail a,
.breadcrumb-current {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
}

.breadcrumb-separator {
  margin: 0 12px;
  color: var(--green);
}

.chapter-opener {
  display: grid;
  grid-template-columns: minmax(0, 1.45fr) minmax(280px, 0.55fr);
  gap: 88px;
  align-items: end;
  padding: 88px 0 76px;
}

.chapter-kicker,
.section-tab,
.claim-label,
.source-label,
.recap-label,
.eyebrow-note {
  margin: 0;
  color: var(--green);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 16px;
  font-weight: 700;
  letter-spacing: 0.12em;
  line-height: 1.35;
  text-transform: uppercase;
}

.chapter-title {
  max-width: 850px;
  margin: 18px 0 24px;
  font-family: Arial, Helvetica, sans-serif;
  font-size: clamp(58px, 7.2vw, 108px);
  font-weight: 600;
  letter-spacing: -0.055em;
  line-height: 0.92;
}

.chapter-deck {
  max-width: 66ch;
  margin: 0;
  color: #d4dad7;
  font-size: 23px;
  line-height: 1.5;
}

.line-figure {
  min-height: 260px;
  padding: 24px;
  border: 1px solid var(--rule);
  background: var(--panel-deep);
}

.line-figure svg {
  display: block;
  width: 100%;
  height: auto;
}

.figure-caption {
  max-width: 34ch;
  margin: 18px 0 0;
  color: var(--ash);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 16px;
  line-height: 1.5;
}

.immunoblot-divider {
  display: grid;
  gap: 6px;
  padding: 12px 0;
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
}

.immunoblot-divider::before,
.immunoblot-divider::after {
  content: "";
  display: block;
  height: 3px;
  background: linear-gradient(90deg, var(--green) 0 18%, #1c302b 18% 42%, var(--green) 42% 55%, #17201f 55% 100%);
}

.chapter-section {
  padding: 82px 0;
}

.section-intro {
  display: grid;
  grid-template-columns: 240px minmax(0, var(--measure));
  gap: 56px;
  align-items: start;
  margin-bottom: 42px;
}

.section-tab {
  display: inline-block;
  width: max-content;
  padding: 10px 13px 9px;
  border: 1px solid var(--green);
}

.section-heading {
  margin: 0 0 18px;
  font-size: clamp(34px, 4vw, 58px);
  font-weight: 400;
  letter-spacing: -0.025em;
  line-height: 1.08;
}

.section-copy,
.section-copy p {
  max-width: var(--measure);
}

.section-copy p:first-child {
  margin-top: 0;
}

.answer-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 22px;
}

.answer-card,
.evidence-card,
.cost-panel,
.visit-panel,
.checklist-panel {
  border-top: 4px solid var(--green);
  background: var(--panel);
  box-shadow: inset 0 0 0 1px var(--rule);
}

.answer-card {
  min-height: 100%;
  padding: 30px;
}

.answer-card h3,
.evidence-card h2,
.evidence-card h3,
.visit-panel h3,
.cost-panel h3 {
  margin: 8px 0 16px;
  font-size: 27px;
  font-weight: 400;
  line-height: 1.2;
}

.answer-card p,
.evidence-card p,
.visit-panel p,
.cost-panel p,
.checklist-item span {
  font-size: 18px;
}

.answer-card p:last-child,
.evidence-card p:last-child,
.visit-panel p:last-child,
.cost-panel p:last-child {
  margin-bottom: 0;
}

.source-pair {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 14px;
  align-items: center;
  margin-top: 26px;
  padding-top: 18px;
  border-top: 1px solid var(--rule);
  color: var(--ash);
  font-family: Arial, Helvetica, sans-serif;
  line-height: 1.4;
}

.source-label {
  color: var(--ash);
  font-size: 14px;
}

.source-link {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 4px 0;
  font-size: 16px;
}

.plain-summary {
  display: grid;
  grid-template-columns: 0.75fr 1.25fr;
  gap: 56px;
  align-items: start;
}

.plain-summary-mark {
  margin: 0;
  color: var(--green);
  font-family: Arial, Helvetica, sans-serif;
  font-size: clamp(76px, 11vw, 158px);
  font-weight: 700;
  letter-spacing: -0.08em;
  line-height: 0.76;
}

.plain-summary-text {
  max-width: 680px;
  margin: 0;
  font-size: clamp(28px, 3.4vw, 48px);
  line-height: 1.25;
}

.chapter-recap {
  display: grid;
  grid-template-columns: 240px minmax(0, 720px);
  gap: 56px;
  margin: 12px 0 76px;
  padding: 34px 0;
  border-top: 1px solid var(--green);
  border-bottom: 1px solid var(--green);
}

.chapter-recap p {
  margin: 0;
  font-size: 21px;
}

.next-chapter {
  display: flex;
  justify-content: flex-end;
  padding-bottom: 90px;
}

.next-link {
  display: inline-grid;
  min-width: 330px;
  min-height: 72px;
  padding: 16px 22px;
  border: 1px solid var(--green);
  color: var(--paper);
  font-family: Arial, Helvetica, sans-serif;
  text-decoration: none;
}

.next-link small {
  color: var(--green);
  font-size: 16px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.next-link span {
  font-size: 19px;
}

.visit-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}

.visit-panel {
  padding: 32px;
}

.visit-list,
.evidence-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.visit-step {
  display: grid;
  grid-template-columns: 54px 1fr;
  gap: 18px;
  padding: 21px 0;
  border-top: 1px solid var(--rule);
}

.visit-step:first-child {
  border-top: 0;
}

.step-marker {
  display: grid;
  width: 42px;
  height: 42px;
  place-items: center;
  border: 1px solid var(--green);
  color: var(--green);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 16px;
}

.visit-step h3 {
  margin: 0 0 6px;
  font-size: 21px;
  font-weight: 400;
}

.visit-step p {
  margin: 0;
  color: #cbd1ce;
  font-size: 17px;
}

.checklist-panel {
  padding: 38px;
}

.checklist-header {
  display: flex;
  gap: 24px;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 28px;
}

.checklist-title {
  margin: 0;
  font-size: 32px;
  font-weight: 400;
}

.print-button {
  min-width: 190px;
  min-height: 52px;
  padding: 10px 18px;
  border: 1px solid var(--green);
  background: transparent;
  color: var(--paper);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 16px;
  cursor: pointer;
}

.print-button:hover,
.print-button:focus-visible {
  background: var(--green);
  color: var(--obsidian);
}

.checklist-items {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0 28px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.checklist-item {
  display: grid;
  grid-template-columns: 25px 1fr;
  gap: 14px;
  align-items: start;
  padding: 19px 0;
  border-top: 1px solid var(--rule);
}

.check-box {
  width: 22px;
  height: 22px;
  margin-top: 4px;
  border: 1px solid var(--green);
}

.cost-panel {
  display: grid;
  grid-template-columns: 0.8fr 1.2fr;
  gap: 46px;
  padding: 38px;
}

.cost-questions {
  margin: 0;
  padding-left: 23px;
}

.cost-questions li {
  margin: 0 0 13px;
  padding-left: 8px;
}

.evidence-stack {
  display: grid;
  gap: 24px;
}

.evidence-card {
  display: grid;
  grid-template-columns: 230px minmax(0, 1fr) 230px;
  gap: 36px;
  padding: 34px;
}

.evidence-card h2,
.evidence-card h3,
.evidence-card p {
  margin-top: 0;
}

.evidence-source {
  align-self: start;
  padding-left: 22px;
  border-left: 1px solid var(--rule);
  color: var(--ash);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 16px;
  line-height: 1.45;
}

.evidence-source a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
}

.myth-correction {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}

.myth-panel,
.correction-panel {
  padding: 34px;
  border: 1px solid var(--rule);
}

.myth-panel {
  color: var(--ash);
  background: #101217;
}

.correction-panel {
  border-color: var(--green);
  background: #102019;
}

.myth-panel h3,
.correction-panel h3 {
  margin-top: 0;
  font-size: 25px;
  font-weight: 400;
}

.site-footer {
  padding: 34px 0 40px;
  border-top: 1px solid var(--rule);
  color: var(--ash);
}

.site-footer p {
  max-width: 760px;
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  font-size: 16px;
  line-height: 1.55;
}

.error-page {
  min-height: calc(100vh - 72px);
  display: grid;
  align-content: center;
  max-width: 820px;
  padding: 72px 0;
}

.error-page h1 {
  margin: 14px 0 26px;
  font-family: Arial, Helvetica, sans-serif;
  font-size: clamp(58px, 9vw, 116px);
  font-weight: 600;
  letter-spacing: -0.055em;
  line-height: 0.93;
}

.error-page p {
  max-width: 58ch;
  font-size: 21px;
}

.home-link {
  display: inline-flex;
  align-items: center;
  width: max-content;
  min-height: 52px;
  margin-top: 18px;
  padding: 9px 18px;
  border: 1px solid var(--green);
  color: var(--paper);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 16px;
  text-decoration: none;
}

@media (max-width: 900px) {
  .page-shell {
    width: min(100% - 48px, 760px);
  }

  .chapter-opener,
  .section-intro,
  .plain-summary,
  .chapter-recap,
  .visit-layout,
  .cost-panel,
  .evidence-card {
    grid-template-columns: 1fr;
  }

  .chapter-opener,
  .section-intro,
  .plain-summary,
  .chapter-recap,
  .cost-panel,
  .evidence-card {
    gap: 32px;
  }

  .chapter-opener {
    align-items: start;
    padding-top: 64px;
  }

  .line-figure {
    max-width: 460px;
  }

  .answer-grid {
    grid-template-columns: 1fr;
  }

  .evidence-source {
    padding-top: 20px;
    padding-left: 0;
    border-top: 1px solid var(--rule);
    border-left: 0;
  }
}

@media (max-width: 600px) {
  body {
    font-size: 17px;
  }

  .page-shell {
    width: calc(100% - 32px);
  }

  .breadcrumb-trail {
    min-height: 60px;
  }

  .chapter-opener {
    gap: 42px;
    padding: 54px 0 50px;
  }

  .chapter-title {
    font-size: clamp(48px, 15vw, 68px);
  }

  .chapter-deck {
    font-size: 20px;
  }

  .line-figure {
    min-height: 0;
    padding: 18px;
  }

  .chapter-section {
    padding: 60px 0;
  }

  .section-heading {
    font-size: 36px;
  }

  .answer-card,
  .evidence-card,
  .visit-panel,
  .cost-panel,
  .checklist-panel,
  .myth-panel,
  .correction-panel {
    padding: 25px;
  }

  .checklist-header {
    align-items: stretch;
    flex-direction: column;
  }

  .print-button {
    width: 100%;
  }

  .checklist-items,
  .myth-correction {
    grid-template-columns: 1fr;
  }

  .plain-summary-mark {
    font-size: 92px;
  }

  .next-chapter {
    justify-content: stretch;
  }

  .next-link {
    width: 100%;
    min-width: 0;
  }
}

@media print {
  :root {
    color-scheme: light;
  }

  body {
    background: #ffffff;
    color: #000000;
  }

  .breadcrumb-trail,
  .chapter-opener,
  .immunoblot-divider,
  .chapter-section:not(.print-section),
  .chapter-recap,
  .next-chapter,
  .site-footer,
  .print-button {
    display: none;
  }

  .page-shell {
    width: 100%;
  }

  .print-section {
    padding: 0;
  }

  .print-section .section-intro {
    display: block;
    margin-bottom: 20px;
  }

  .print-section .section-tab {
    color: #000000;
    border-color: #000000;
  }

  .checklist-panel {
    padding: 0;
    border: 0;
    box-shadow: none;
  }

  .checklist-item {
    border-color: #777777;
    break-inside: avoid;
  }

  .check-box {
    border-color: #000000;
  }
}