:root {
  color-scheme: light;
  --ink: #15312d;
  --muted: #526762;
  --paper: #fbfaf4;
  --surface: #ffffff;
  --soft: #eef5ee;
  --line: #ccd9d3;
  --brand: #006b5d;
  --brand-dark: #004c43;
  --accent: #e5a93f;
  --warning: #6f4b00;
  --warning-bg: #fff4d7;
  --danger: #7b2c2c;
  --danger-bg: #fff0ee;
  --radius: 1.25rem;
  --shadow: 0 12px 34px rgba(27, 63, 56, 0.08);
  font-family: -apple-system, BlinkMacSystemFont, "Apple SD Gothic Neo", "Noto Sans KR", "Segoe UI", sans-serif;
  font-size: 18px;
  line-height: 1.65;
}

* {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 90% 2%, rgba(229, 169, 63, 0.13), transparent 24rem),
    var(--paper);
}

a {
  color: var(--brand-dark);
  text-underline-offset: 0.2em;
  text-decoration-thickness: 0.1em;
}

a:hover {
  text-decoration-thickness: 0.16em;
}

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

.skip-link {
  position: fixed;
  z-index: 20;
  top: 0.75rem;
  left: 0.75rem;
  padding: 0.75rem 1rem;
  transform: translateY(-180%);
  border-radius: 0.75rem;
  color: #fff;
  background: var(--brand-dark);
}

.skip-link:focus {
  transform: translateY(0);
}

.site-header,
.page-shell,
.site-footer {
  width: min(72rem, calc(100% - 2rem));
  margin-inline: auto;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: 5rem;
  border-bottom: 1px solid var(--line);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  min-height: 3.5rem;
  color: var(--ink);
  font-weight: 800;
  text-decoration: none;
}

.brand-mark {
  display: inline-grid;
  width: 2.4rem;
  height: 2.4rem;
  place-items: center;
  border-radius: 50%;
  color: white;
  background: var(--brand);
  font-size: 1.35rem;
}

.language-switcher {
  display: inline-flex;
  gap: 0.25rem;
  padding: 0.25rem;
  border: 1px solid var(--line);
  border-radius: 0.9rem;
  background: var(--surface);
}

.language-switcher button {
  min-width: 3.5rem;
  min-height: 3rem;
  padding: 0.45rem 0.8rem;
  border: 0;
  border-radius: 0.65rem;
  color: var(--muted);
  background: transparent;
  font: inherit;
  font-weight: 750;
  cursor: pointer;
}

.language-switcher button[aria-pressed="true"] {
  color: white;
  background: var(--brand);
}

[data-lang="en"] {
  display: none !important;
}

html[lang="en"] [data-lang="ko"] {
  display: none !important;
}

html[lang="en"] [data-lang="en"] {
  display: revert !important;
}

.page-shell {
  padding-block: clamp(2.5rem, 6vw, 5.5rem);
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) minmax(17rem, 0.6fr);
  gap: clamp(1.5rem, 4vw, 4rem);
  align-items: center;
  margin-bottom: 4rem;
}

.eyebrow,
.study-type {
  color: var(--brand);
  font-size: 0.88rem;
  font-weight: 850;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1,
h2,
h3 {
  line-height: 1.22;
  text-wrap: balance;
}

h1 {
  max-width: 18ch;
  margin: 0.35rem 0 1.2rem;
  font-size: clamp(2.35rem, 6vw, 4.75rem);
  letter-spacing: -0.045em;
}

h2 {
  margin: 0 0 1.25rem;
  font-size: clamp(1.65rem, 3.5vw, 2.5rem);
  letter-spacing: -0.025em;
}

h3 {
  margin: 0 0 0.6rem;
  font-size: 1.25rem;
}

p {
  max-width: 68ch;
}

.lede {
  color: var(--muted);
  font-size: clamp(1.05rem, 2.1vw, 1.28rem);
}

.hero-note,
.notice,
.caution {
  padding: 1.35rem;
  border-radius: var(--radius);
}

.hero-note {
  border: 1px solid var(--line);
  background: var(--surface);
  box-shadow: var(--shadow);
}

.hero-note strong {
  display: block;
  margin-bottom: 0.45rem;
  font-size: 1.2rem;
}

.notice {
  margin-block: 1.5rem;
  border-left: 0.4rem solid var(--accent);
  color: var(--warning);
  background: var(--warning-bg);
}

.caution {
  border-left: 0.4rem solid var(--danger);
  color: var(--danger);
  background: var(--danger-bg);
}

.section {
  margin-block: 4.5rem;
}

.section-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 1.5rem;
  margin-bottom: 1.5rem;
}

.section-heading p {
  margin: 0;
  color: var(--muted);
}

.evidence-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
}

.evidence-card {
  display: flex;
  flex-direction: column;
  min-height: 20rem;
  padding: clamp(1.25rem, 3vw, 1.8rem);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  box-shadow: var(--shadow);
}

.evidence-card p {
  color: var(--muted);
}

.evidence-card .card-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 3.5rem;
  margin-top: auto;
  padding: 0.7rem 1rem;
  border-radius: 0.85rem;
  color: white;
  background: var(--brand);
  font-weight: 800;
  text-decoration: none;
}

.evidence-card .card-link:hover {
  background: var(--brand-dark);
}

.principles {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
  padding: 0;
  list-style: none;
}

.principles li,
.fact-card {
  padding: 1.4rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--soft);
}

.principles strong {
  display: block;
  margin-bottom: 0.45rem;
  font-size: 1.2rem;
}

.breadcrumb {
  margin: 0 0 1.5rem;
}

.study-hero {
  max-width: 58rem;
  margin-bottom: 3rem;
}

.study-hero h1 {
  max-width: 22ch;
  font-size: clamp(2.1rem, 5vw, 3.8rem);
}

.citation {
  color: var(--muted);
}

.key-result {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(16rem, 0.7fr);
  gap: 1rem;
  margin-block: 2rem;
}

.result-value {
  padding: clamp(1.4rem, 4vw, 2.25rem);
  border-radius: var(--radius);
  color: white;
  background: var(--brand-dark);
}

.result-value .big-number {
  display: block;
  margin-block: 0.4rem;
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 900;
  line-height: 1.05;
}

.result-context {
  padding: 1.5rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}

.details-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
}

.details-grid dl,
.record-list {
  margin: 0;
}

.details-grid dt,
.record-list dt {
  margin-top: 1rem;
  color: var(--muted);
  font-size: 0.9rem;
  font-weight: 800;
}

.details-grid dd,
.record-list dd {
  margin: 0.15rem 0 0;
}

.link-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  padding: 0;
  list-style: none;
}

.link-list a {
  display: inline-flex;
  align-items: center;
  min-height: 3.5rem;
  padding: 0.7rem 1rem;
  border: 2px solid var(--brand);
  border-radius: 0.85rem;
  font-weight: 800;
  text-decoration: none;
}

.site-footer {
  padding-block: 2rem 3rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
}

.site-footer p {
  margin-block: 0.4rem;
}

.mono-link {
  overflow-wrap: anywhere;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.85rem;
}

@media (max-width: 760px) {
  :root {
    font-size: 17px;
  }

  .site-header {
    align-items: flex-start;
    padding-block: 0.75rem;
  }

  .hero,
  .key-result,
  .evidence-grid,
  .details-grid,
  .principles {
    grid-template-columns: 1fr;
  }

  .section-heading {
    display: block;
  }
}

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

@media (prefers-contrast: more) {
  :root {
    --muted: #2f4540;
    --line: #667a74;
  }

  .evidence-card,
  .hero-note,
  .fact-card,
  .principles li {
    box-shadow: none;
  }
}