:root {
  --ink: #152019;
  --forest: #10231c;
  --green: #1d5b43;
  --mint: #bde3cd;
  --lime: #d7ef8c;
  --paper: #f4f2eb;
  --paper-2: #e9e6dc;
  --line: rgba(21, 32, 25, 0.18);
  --white: #fcfbf7;
  --orange: #ef8354;
  --blue: #6c8fa3;
  --mono: "DM Mono", monospace;
  --sans: "Noto Sans KR", sans-serif;
  --serif: "Newsreader", serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: var(--sans);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
.skip-link {
  position: fixed;
  top: 8px;
  left: 8px;
  z-index: 100;
  padding: 10px 14px;
  background: var(--white);
  transform: translateY(-150%);
}
.skip-link:focus { transform: translateY(0); }

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  min-height: 72px;
  padding: 0 5vw;
  border-bottom: 1px solid var(--line);
  background: rgba(244, 242, 235, 0.94);
  backdrop-filter: blur(16px);
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .05em;
  text-decoration: none;
  text-transform: uppercase;
}
.brand-mark {
  display: grid;
  place-items: center;
  width: 27px;
  height: 27px;
  border-radius: 50%;
  color: var(--white);
  background: var(--forest);
  font-family: var(--serif);
  font-size: 16px;
}
nav { display: flex; gap: 28px; }
nav a, .header-link {
  font-size: 12px;
  font-weight: 600;
  text-decoration: none;
}
nav a { color: #526057; }
nav a:hover, nav a:focus-visible { color: var(--green); }
.header-link { justify-self: end; }

.hero {
  display: grid;
  grid-template-columns: 1.15fr .85fr;
  gap: clamp(40px, 7vw, 110px);
  align-items: center;
  min-height: calc(100vh - 72px);
  padding: 9vh 7vw 10vh;
  border-bottom: 1px solid var(--line);
}
.eyebrow, .section-index {
  margin: 0 0 24px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .12em;
  text-transform: uppercase;
}
.hero h1 {
  margin: 0;
  font-size: clamp(52px, 7vw, 104px);
  font-weight: 600;
  letter-spacing: -.065em;
  line-height: .97;
}
.hero h1 em {
  color: var(--green);
  font-family: var(--serif);
  font-weight: 500;
}
.hero-lede {
  max-width: 660px;
  margin: 38px 0 0;
  color: #4e5a52;
  font-size: clamp(16px, 1.5vw, 20px);
  line-height: 1.8;
  word-break: keep-all;
}
.hero-actions, .closing-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: 38px;
}
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0 21px;
  border: 1px solid var(--forest);
  border-radius: 3px;
  font-size: 13px;
  font-weight: 700;
  text-decoration: none;
  transition: transform .2s ease, background .2s ease;
}
.button:hover { transform: translateY(-2px); }
.button.primary { color: var(--white); background: var(--forest); }
.button.secondary { background: transparent; }

.study-record {
  position: relative;
  padding: 28px;
  border: 1px solid rgba(255,255,255,.15);
  border-radius: 4px;
  color: var(--white);
  background: var(--forest);
  box-shadow: 24px 24px 0 var(--mint);
}
.record-topline {
  display: flex;
  justify-content: space-between;
  padding-bottom: 20px;
  border-bottom: 1px solid rgba(255,255,255,.15);
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: .1em;
}
.status { color: var(--lime); }
.status i {
  display: inline-block;
  width: 7px;
  height: 7px;
  margin-right: 7px;
  border-radius: 50%;
  background: var(--lime);
}
.record-question { padding: 30px 0; }
.record-question span, .record-grid span {
  color: #a8b6ad;
  font-family: var(--mono);
  font-size: 10px;
  text-transform: uppercase;
}
.record-question p { margin: 9px 0 0; font-size: 19px; font-weight: 600; }
.record-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  border-top: 1px solid rgba(255,255,255,.15);
  border-left: 1px solid rgba(255,255,255,.15);
}
.record-grid div {
  display: flex;
  flex-direction: column;
  padding: 18px;
  border-right: 1px solid rgba(255,255,255,.15);
  border-bottom: 1px solid rgba(255,255,255,.15);
}
.record-grid strong { font-family: var(--serif); font-size: 34px; font-weight: 500; }
.record-note { margin: 24px 0 0; color: #bdc8c1; font-size: 12px; line-height: 1.8; }

.statement {
  display: grid;
  grid-template-columns: .45fr 1.55fr;
  gap: 50px;
  padding: 12vh 7vw;
}
.statement h2 {
  max-width: 980px;
  margin: 0;
  font-size: clamp(34px, 4.6vw, 66px);
  font-weight: 500;
  letter-spacing: -.045em;
  line-height: 1.25;
  word-break: keep-all;
}
.statement h2 span { color: var(--green); font-family: var(--serif); font-style: italic; }
.statement-notes {
  grid-column: 2;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 40px;
  margin-top: 30px;
  color: #58635b;
  font-size: 14px;
}

.section-shell { padding: 11vh 7vw; }
.section-heading {
  display: grid;
  grid-template-columns: 1.25fr .75fr;
  gap: 60px;
  align-items: end;
  margin-bottom: 64px;
}
.section-heading h2 {
  margin: 0;
  font-size: clamp(35px, 4.3vw, 60px);
  font-weight: 600;
  letter-spacing: -.05em;
  line-height: 1.14;
  word-break: keep-all;
}
.section-heading > p { margin: 0; color: #667168; font-size: 14px; word-break: keep-all; }

.journey { border-top: 1px solid var(--line); }
.journey-list { margin: 0; padding: 0; list-style: none; border-top: 1px solid var(--ink); }
.journey-list li {
  display: grid;
  grid-template-columns: 70px 1fr auto;
  gap: 24px;
  align-items: center;
  padding: 28px 6px;
  border-bottom: 1px solid var(--line);
}
.step-number { font-family: var(--serif); font-size: 28px; }
.journey-list h3 { margin: 0 0 5px; font-size: 18px; }
.journey-list p { margin: 0; color: #647067; font-size: 13px; }
.learning-tag {
  padding: 5px 10px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--green);
  font-family: var(--mono);
  font-size: 9px;
  text-transform: uppercase;
}

.evidence { color: var(--white); background: var(--forest); }
.section-heading.light > p { color: #aebbb3; }
.metric-grid { display: grid; grid-template-columns: repeat(4, 1fr); border: 1px solid rgba(255,255,255,.17); }
.metric-grid article { padding: 26px; border-right: 1px solid rgba(255,255,255,.17); }
.metric-grid article:last-child { border-right: 0; }
.metric-grid span, .panel-heading span, .causal-result > span {
  font-family: var(--mono);
  font-size: 9px;
  letter-spacing: .1em;
  text-transform: uppercase;
}
.metric-grid strong { display: block; margin: 16px 0 4px; color: var(--lime); font-family: var(--serif); font-size: 48px; font-weight: 500; }
.metric-grid p { margin: 0; color: #9fada4; font-size: 11px; }
.comparison-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; margin-top: 18px; }
.panel { padding: 30px; border: 1px solid rgba(255,255,255,.17); background: rgba(255,255,255,.035); }
.panel-heading { display: flex; justify-content: space-between; gap: 20px; }
.panel-heading h3 { margin: 7px 0 0; font-size: 20px; word-break: keep-all; }
.panel-badge { align-self: flex-start; padding: 5px 8px; border: 1px solid rgba(255,255,255,.2); border-radius: 999px; color: var(--lime); white-space: nowrap; }
.bar-chart { margin-top: 30px; }
.bar-group { margin-bottom: 23px; }
.bar-label { display: flex; justify-content: space-between; margin-bottom: 6px; font-family: var(--mono); font-size: 10px; }
.track { height: 7px; margin-bottom: 4px; background: rgba(255,255,255,.09); }
.bar { display: block; width: var(--value); height: 100%; }
.bar.logistic, .logistic-dot { background: var(--lime); }
.bar.boosting, .boosting-dot { background: var(--blue); }
.legend { display: flex; gap: 20px; color: #aab5ae; font-size: 10px; }
.legend-dot { display: inline-block; width: 7px; height: 7px; margin-right: 6px; border-radius: 50%; }
.panel-conclusion { margin: 24px 0 0; padding-top: 18px; border-top: 1px solid rgba(255,255,255,.12); color: #bdc7c1; font-size: 12px; }
.interval { margin-top: 30px; }
.interval-scale { display: flex; justify-content: space-between; color: #8f9f95; font-family: var(--mono); font-size: 9px; }
.interval-line { position: relative; height: 36px; margin: 3px 0 12px; }
.interval-line::before { content: ""; position: absolute; top: 17px; left: 0; width: 100%; height: 1px; background: rgba(255,255,255,.2); }
.zero-line { position: absolute; z-index: 1; top: 5px; bottom: 5px; left: 17%; width: 1px; background: var(--orange); }
.confidence-line { position: absolute; z-index: 2; top: 15px; left: 16.7%; width: 81%; height: 5px; background: var(--mint); }
.interval-line b { position: absolute; z-index: 3; top: 10px; left: 58%; width: 15px; height: 15px; border: 3px solid var(--forest); border-radius: 50%; background: var(--lime); }
.interval > p { display: inline-block; margin: 0 18px 0 0; font-family: var(--mono); font-size: 10px; }
.interval > p strong { color: var(--lime); font-size: 18px; }
.interval > p span { color: var(--mint); }

.capacity { border-bottom: 1px solid var(--line); }
.capacity-lab { border: 1px solid var(--ink); }
.capacity-controls { display: flex; justify-content: space-between; align-items: center; padding: 18px 22px; border-bottom: 1px solid var(--line); font-size: 12px; font-weight: 700; }
.segmented { display: flex; border: 1px solid var(--ink); }
.segmented button {
  min-width: 58px;
  padding: 8px 12px;
  border: 0;
  border-right: 1px solid var(--ink);
  color: var(--ink);
  background: transparent;
  font-family: var(--mono);
  cursor: pointer;
}
.segmented button:last-child { border-right: 0; }
.segmented button.active { color: var(--white); background: var(--green); }
.capacity-result { display: grid; grid-template-columns: repeat(4, 1fr); }
.capacity-result div { display: flex; flex-direction: column; padding: 30px 24px; border-right: 1px solid var(--line); }
.capacity-result div:last-child { border-right: 0; }
.capacity-result span { color: #657168; font-size: 11px; }
.capacity-result strong { margin-top: 8px; font-family: var(--serif); font-size: 40px; font-weight: 500; }
.capacity-result small { margin-left: 3px; color: #6d796f; font-family: var(--sans); font-size: 12px; }
.capacity-insight { margin: 0; padding: 18px 24px; color: var(--forest); background: var(--mint); font-size: 12px; }

.judgment-cards { display: grid; grid-template-columns: repeat(4, 1fr); border-top: 1px solid var(--ink); border-left: 1px solid var(--line); }
.judgment-cards article { min-height: 270px; padding: 24px; border-right: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.judgment-cards span { font-family: var(--serif); font-size: 28px; }
.judgment-cards h3 { margin: 46px 0 12px; font-size: 17px; }
.judgment-cards p { margin: 0; color: #68746b; font-size: 12px; }

.debug { background: var(--paper-2); }
.debug-log { border-top: 1px solid var(--ink); }
.debug-row { display: grid; grid-template-columns: .6fr 1fr 1.25fr; gap: 25px; padding: 22px 5px; border-bottom: 1px solid var(--line); font-size: 12px; }
.debug-row code { color: var(--green); font-family: var(--mono); font-size: 11px; }
.debug-row p { margin: 0; }
.debug-row strong { margin-right: 8px; font-size: 10px; }

.causal { display: grid; grid-template-columns: 1.1fr .9fr; gap: 8vw; align-items: center; color: var(--white); background: #18352b; }
.causal h2 { margin: 0; font-size: clamp(38px, 4.6vw, 64px); letter-spacing: -.05em; line-height: 1.13; }
.causal-copy > p:not(.section-index) { max-width: 650px; color: #b7c6bd; font-size: 14px; }
.causal-warning { margin-top: 30px; padding: 18px; border-left: 3px solid var(--orange); background: rgba(255,255,255,.06); }
.causal-warning span { color: var(--orange); font-family: var(--mono); font-size: 9px; }
.causal-warning p { margin: 6px 0 0; font-size: 11px; }
.causal-result { padding: 34px; border: 1px solid rgba(255,255,255,.2); }
.causal-result > strong { display: block; margin: 20px 0 0; color: var(--lime); font-family: var(--serif); font-size: 84px; font-weight: 500; line-height: 1; }
.causal-result > strong small { font-size: 28px; }
.causal-result > p { margin: 4px 0 28px; color: #b2c0b7; font-family: var(--mono); font-size: 10px; }
.causal-result dl { margin: 0; }
.causal-result dl div { display: flex; justify-content: space-between; padding: 11px 0; border-top: 1px solid rgba(255,255,255,.14); font-size: 11px; }
.causal-result dt { color: #99aa9f; }
.causal-result dd { margin: 0; }

.limits-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.limits-grid > div { padding: 28px; border: 1px solid var(--line); }
.limits-grid span { font-family: var(--mono); font-size: 10px; letter-spacing: .08em; }
.limits-grid ul { margin: 24px 0 0; padding: 0; list-style: none; }
.limits-grid li { padding: 12px 0; border-top: 1px solid var(--line); font-size: 13px; }
.limits-grid li::before { content: "→"; margin-right: 12px; color: var(--green); }

.closing { padding: 13vh 7vw; text-align: center; color: var(--white); background: var(--forest); }
.closing > p { font-family: var(--mono); font-size: 10px; letter-spacing: .12em; }
.closing h2 { margin: 25px auto 0; max-width: 980px; font-size: clamp(38px, 5vw, 70px); font-weight: 500; letter-spacing: -.05em; line-height: 1.2; word-break: keep-all; }
.closing-actions { justify-content: center; }
.light-button { color: var(--forest) !important; background: var(--lime) !important; }
.text-link { margin-left: 14px; color: #afbeb5; font-size: 11px; text-underline-offset: 4px; }
footer { display: flex; justify-content: space-between; padding: 22px 5vw; border-top: 1px solid rgba(255,255,255,.12); color: #9eaca3; background: var(--forest); font-family: var(--mono); font-size: 9px; }

.reveal { opacity: 0; transform: translateY(18px); transition: opacity .7s ease, transform .7s ease; }
.reveal.visible { opacity: 1; transform: translateY(0); }

@media (max-width: 900px) {
  .site-header { grid-template-columns: 1fr auto; }
  nav { display: none; }
  .hero, .statement, .section-heading, .causal { grid-template-columns: 1fr; }
  .hero { min-height: auto; padding-top: 80px; }
  .study-record { box-shadow: 12px 12px 0 var(--mint); }
  .statement-notes, .statement-notes { grid-column: 1; }
  .metric-grid, .judgment-cards { grid-template-columns: repeat(2, 1fr); }
  .metric-grid article:nth-child(2) { border-right: 0; }
  .metric-grid article:nth-child(-n+2) { border-bottom: 1px solid rgba(255,255,255,.17); }
  .comparison-grid { grid-template-columns: 1fr; }
  .capacity-result { grid-template-columns: repeat(2, 1fr); }
  .capacity-result div:nth-child(2) { border-right: 0; }
  .capacity-result div:nth-child(-n+2) { border-bottom: 1px solid var(--line); }
}

@media (max-width: 600px) {
  .site-header { min-height: 60px; padding: 0 20px; }
  .brand span:last-child { display: none; }
  .hero, .statement, .section-shell, .closing { padding-left: 22px; padding-right: 22px; }
  .hero h1 { font-size: 49px; }
  .hero-actions, .closing-actions { align-items: stretch; flex-direction: column; }
  .statement-notes, .metric-grid, .judgment-cards, .limits-grid { grid-template-columns: 1fr; }
  .metric-grid article, .metric-grid article:nth-child(2) { border-right: 0; border-bottom: 1px solid rgba(255,255,255,.17); }
  .metric-grid article:last-child { border-bottom: 0; }
  .journey-list li { grid-template-columns: 44px 1fr; }
  .learning-tag { grid-column: 2; justify-self: start; }
  .capacity-controls { align-items: flex-start; flex-direction: column; gap: 14px; }
  .segmented { width: 100%; }
  .segmented button { flex: 1; min-width: 0; }
  .capacity-result { grid-template-columns: 1fr 1fr; }
  .capacity-result strong { font-size: 32px; }
  .debug-row { grid-template-columns: 1fr; gap: 7px; }
  .causal-result > strong { font-size: 68px; }
  footer { gap: 20px; flex-direction: column; }
  .text-link { margin-left: 0; text-align: center; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
}