/* ===== Design tokens ===== */
:root{
  --ink: #16181b;
  --ink-soft: #54565b;
  --paper: #ffffff;
  --paper-2: #f6f6f4;
  --paper-3: #ececea;
  --line: rgba(20,20,20,0.12);
  --accent: #1f5d4f;
  --accent-dark: #163f37;
  --accent-soft: #e7efec;
  --shadow: 0 16px 40px -20px rgba(20,20,20,0.18);
  --radius: 10px;
  --serif: "Fraunces", "Iowan Old Style", "Palatino Linotype", serif;
  --sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, monospace;
}

*{ box-sizing: border-box; }
html{ scroll-behavior: smooth; }
body{
  margin:0;
  font-family: var(--sans);
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
  line-height: 1.65;
}
img{ max-width:100%; display:block; }
a{ color: inherit; text-decoration: none; }
code{ font-family: var(--mono); font-size: 0.92em; background: var(--paper-3); padding: 0.1em 0.4em; border-radius: 4px; }

/* ===== Layout helpers ===== */
.section-inner, .nav-inner, .hero-inner, .footer-inner, .stats-inner{
  max-width: 1040px;
  margin: 0 auto;
  padding: 0 28px;
}
.section{ padding: 88px 0; }
.section-muted{ background: var(--paper-2); }
.kicker{
  display:block;
  font-family: var(--mono);
  letter-spacing: .1em;
  text-transform: uppercase;
  font-size: 12px;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 14px;
}
.h2{
  font-family: var(--serif);
  font-weight: 600;
  font-size: clamp(26px, 3.6vw, 36px);
  line-height: 1.2;
  margin: 0 0 20px;
  max-width: 26ch;
  color: var(--ink);
}
.section-lede{
  font-size: 17.5px;
  color: var(--ink-soft);
  max-width: 68ch;
  margin: 0 0 48px;
}
.text-link{ color: var(--accent); text-decoration: underline; text-decoration-color: rgba(31,93,79,0.3); text-underline-offset: 3px; }
.text-link:hover{ text-decoration-color: var(--accent); }

/* ===== Nav ===== */
.nav{
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}
.nav-inner{
  display:flex;
  align-items:center;
  justify-content: space-between;
  height: 64px;
}
.brand{ font-family: var(--serif); font-weight:600; font-size: 19px; color: var(--ink); }
.nav-links{ display:flex; gap: 30px; font-size: 14.5px; font-weight: 500; }
.nav-links a{ color: var(--ink-soft); transition: color .15s; }
.nav-links a:hover{ color: var(--accent); }
.nav-toggle{ display:none; }

/* ===== Hero ===== */
.hero{
  padding: 92px 0 56px;
  background: var(--paper);
  border-bottom: 1px solid var(--line);
}
.hero-inner{ text-align:center; max-width: 760px; }
.eyebrow{
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--ink-soft);
  margin: 0 0 20px;
}
.title{
  font-family: var(--serif);
  font-size: clamp(48px, 9vw, 84px);
  font-weight: 700;
  margin: 0;
  letter-spacing: -0.01em;
  color: var(--ink);
}
.accent-text{ color: var(--accent); }
.subtitle{
  font-family: var(--serif);
  font-size: clamp(17px, 2.2vw, 22px);
  font-weight: 500;
  color: var(--ink-soft);
  margin: 14px 0 24px;
}
.lede{
  margin: 0 auto 34px;
  color: var(--ink-soft);
  font-size: 16.5px;
}

.badge-row{ display:flex; gap: 12px; justify-content:center; flex-wrap: wrap; margin-bottom: 14px; }
.badge{
  display:inline-flex; align-items:center; gap: 6px;
  padding: 11px 22px;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  font-weight: 600;
  font-size: 14.5px;
  color: var(--ink);
  background: var(--paper);
  transition: border-color .15s, color .15s, transform .15s;
}
.badge:hover{ border-color: var(--accent); color: var(--accent); transform: translateY(-1px); }
.badge-arrow{ font-size: 13px; opacity: .55; }
.badge-primary{ background: var(--accent); border-color: var(--accent); color: #fff; }
.badge-primary:hover{ background: var(--accent-dark); border-color: var(--accent-dark); color: #fff; }
.badge-primary .badge-arrow{ opacity: .8; }
.badge-note{ font-size: 13.5px; color: var(--ink-soft); opacity: .8; }

/* ===== Stats ===== */
.stats{ background: var(--paper); border-bottom: 1px solid var(--line); }
.stats-inner{
  display:grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 18px;
  padding: 36px 28px;
}
.stat{ text-align:center; padding: 0 8px; }
.stat-num{
  display:block;
  font-family: var(--serif);
  font-weight: 700;
  font-size: clamp(24px, 2.6vw, 30px);
  color: var(--accent);
}
.stat-label{
  display:block;
  font-size: 12.5px;
  color: var(--ink-soft);
  margin-top: 4px;
}

/* ===== Problem / solution rows ===== */
.problem-list{ display:flex; flex-direction:column; }
.problem-row{
  display:grid;
  grid-template-columns: 48px 1fr 1fr;
  gap: 28px;
  padding: 32px 0;
  border-top: 1px solid var(--line);
}
.problem-row:first-child{ border-top: 1px solid var(--ink); }
.problem-num{
  font-family: var(--serif);
  font-size: 20px;
  font-weight: 600;
  color: var(--ink-soft);
  opacity: .5;
}
.problem-statement h3{ font-family: var(--serif); font-size: 19px; margin: 0 0 8px; color: var(--ink); }
.problem-statement p{ margin:0; color: var(--ink-soft); font-size: 15px; }
.answer-label{
  display:block;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 8px;
}
.problem-answer p{ margin:0; color: var(--ink-soft); font-size: 15px; }

/* ===== Pipeline steps ===== */
.steps{ list-style:none; margin:0; padding:0; }
.step{
  display:grid;
  grid-template-columns: 48px 1fr;
  gap: 24px;
  padding-bottom: 36px;
  position: relative;
}
.step:not(:last-child)::before{
  content:"";
  position:absolute;
  left: 23px; top: 38px; bottom: 0;
  width: 1px;
  background: var(--line);
}
.step-num{
  width: 46px; height:46px;
  border-radius:50%;
  border: 1px solid var(--ink);
  display:flex; align-items:center; justify-content:center;
  font-family: var(--serif); font-weight:600; font-size: 17px;
  background: var(--paper-2);
  flex-shrink:0;
}
.step-body h4{ font-family: var(--serif); font-size: 18px; margin: 8px 0 8px; color: var(--ink); }
.step-body p{ margin:0; color: var(--ink-soft); font-size: 15px; max-width: 64ch; }
.formula{
  font-family: var(--mono);
  background: var(--paper-3);
  border-radius: 8px;
  padding: 10px 14px;
  font-size: 13.5px;
  color: var(--ink);
  margin-top: 10px;
  display: inline-block;
}

/* ===== Dataset definition list ===== */
.def-list{ margin:0; }
.def-row{
  display:grid;
  grid-template-columns: 200px 1fr;
  gap: 24px;
  padding: 22px 0;
  border-top: 1px solid var(--line);
}
.def-row:first-child{ border-top: 1px solid var(--ink); }
.def-row dt{ font-family: var(--serif); font-weight:600; font-size: 16.5px; color: var(--ink); }
.def-row dd{ margin:0; color: var(--ink-soft); font-size: 15px; }

/* ===== Panels (evaluation) ===== */
.grid-2{ display:grid; grid-template-columns: 1fr 1fr; gap: 24px; }
.panel{
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px;
}
.panel h3{ font-family: var(--serif); font-size: 18px; margin: 0 0 10px; color: var(--ink); }
.panel p{ color: var(--ink-soft); margin: 0; font-size: 14.8px; }

.compare-row{
  display:grid; grid-template-columns: repeat(4, 1fr); gap: 12px;
  margin-bottom: 36px;
}
.compare-card{
  text-align:center; padding: 16px 10px;
  border-radius: var(--radius);
  background: var(--paper);
  border: 1px solid var(--line);
  font-weight:600; font-size: 14px;
  color: var(--ink-soft);
}
.compare-card span{ display:block; font-size: 11.5px; font-weight:500; color: var(--ink-soft); opacity:.7; margin-top:4px; }
.compare-card-highlight{ border-color: var(--accent); color: var(--ink); }
.compare-card-highlight span{ color: var(--accent); opacity: 1; }

.eval-grid{ margin-bottom: 28px; }
.tag-cloud{ display:flex; flex-wrap:wrap; gap:8px; }
.tag-cloud span{
  font-size: 12px; font-weight:600;
  padding: 5px 11px; border-radius: 999px;
  background: var(--paper-3); color: var(--ink-soft);
}
.status-note{ font-size: 14.5px; color: var(--ink-soft); font-style: italic; margin:0; }

/* ===== Citation ===== */
.bibtex{
  background: var(--ink);
  color: #e9e8e4;
  border-radius: var(--radius);
  padding: 22px 24px;
  overflow-x:auto;
  font-size: 13.5px;
  line-height: 1.7;
}
.bibtex code{ background: none; padding: 0; color: inherit; }

/* ===== Footer ===== */
.footer{ background: var(--paper); border-top: 1px solid var(--line); padding: 40px 0; }
.footer-inner{
  display:flex; flex-wrap:wrap; align-items:center; justify-content:space-between;
  gap: 16px;
}
.footer-brand{ font-family: var(--serif); font-weight:600; color: var(--ink); font-size:16px; }
.footer-links{ display:flex; gap: 22px; font-size: 14px; font-weight:500; color: var(--ink-soft); }
.footer-links a:hover{ color: var(--accent); }
.footer-note{ width:100%; font-size: 12.5px; color: var(--ink-soft); opacity:.7; margin: 4px 0 0; text-align:center; }

/* ===== Responsive ===== */
@media (max-width: 900px){
  .grid-2{ grid-template-columns: 1fr; }
  .stats-inner{ grid-template-columns: repeat(2, 1fr); }
  .compare-row{ grid-template-columns: repeat(2, 1fr); }
  .problem-row{ grid-template-columns: 1fr; gap: 10px; }
  .problem-num{ display:none; }
  .def-row{ grid-template-columns: 1fr; gap: 6px; }
}
@media (max-width: 760px){
  .nav-links{ display:none; }
  .nav-toggle{
    display:flex; flex-direction:column; gap:5px; background:none; border:none; cursor:pointer; padding:8px;
  }
  .nav-toggle span{ width: 22px; height:2px; background: var(--ink); border-radius:2px; }
  .nav.open .nav-links{
    display:flex; flex-direction:column; position:absolute; top:64px; left:0; right:0;
    background: var(--paper); padding: 18px 28px; border-bottom:1px solid var(--line); gap:16px;
  }
}