@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+KR:wght@300;400;500;700;900&family=JetBrains+Mono:wght@400;700&display=swap');

:root {
  --bg: #070B14;
  --card: #0D1421;
  --card2: #111827;
  --border: #1E2D45;
  --border2: #243044;
  --blue: #3B9EFF;
  --blue-dim: #1a3a5c;
  --green: #10D98C;
  --green-dim: #0a2e1f;
  --red: #FF4D6D;
  --red-dim: #2e0f18;
  --orange: #FF8C42;
  --orange-dim: #2e0a0a;
  --purple: #9B6DFF;
  --purple-dim: #1e0f3c;
  --cyan: #00E5FF;
  --yellow: #FFD60A;
  --yellow-dim: #2a2000;
  --pink: #FF6EB4;
  --text: #E8EEF7;
  --muted: #6B7FA0;
  --muted2: #8896B0;
  --glow-blue: 0 0 20px rgba(59,158,255,0.3);
  --glow-green: 0 0 20px rgba(16,217,140,0.3);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Noto Sans KR', sans-serif;
  line-height: 1.6;
  overflow-x: hidden;
  font-size: 1rem;
}

/* ─── NAV ─────────────────────────────────── */
nav {
  position: fixed; top: 0; left: 0; right: 0;
  background: rgba(7,11,20,0.92);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
  z-index: 1000;
  padding: 0 2rem;
  display: flex; align-items: center; gap: 0;
  height: 56px;
}
nav .logo {
  font-size: 0.85rem; font-weight: 700;
  color: var(--blue); letter-spacing: 0.05em;
  margin-right: auto;
  font-family: 'JetBrains Mono', monospace;
}
nav a {
  color: var(--muted); text-decoration: none;
  font-size: 0.78rem; font-weight: 500;
  padding: 0 0.85rem; height: 56px;
  display: flex; align-items: center;
  border-bottom: 2px solid transparent;
  transition: all 0.2s; white-space: nowrap;
}
nav a:hover { color: var(--text); border-bottom-color: var(--blue); }

/* ─── LAYOUT ───────────────────────────────── */
.page { max-width: 1260px; margin: 0 auto; padding: 90px 2rem 60px; }
section { padding: 80px 0 20px; }
.section-header { display: flex; align-items: center; gap: 1rem; margin-bottom: 2.5rem; }
.step-badge {
  background: var(--blue-dim); border: 1px solid var(--blue);
  color: var(--blue); font-size: 0.95rem; font-weight: 700;
  padding: 0.3rem 0.8rem; border-radius: 4px;
  font-family: 'JetBrains Mono', monospace;
  letter-spacing: 0.1em; white-space: nowrap;
}
.step-badge.green { background: var(--green-dim); border-color: var(--green); color: var(--green); }
.step-badge.purple { background: var(--purple-dim); border-color: var(--purple); color: var(--purple); }
.step-badge.orange { background: var(--orange-dim); border-color: var(--orange); color: var(--orange); }
.step-badge.red { background: var(--red-dim); border-color: var(--red); color: var(--red); }
.step-badge.yellow { background: var(--yellow-dim); border-color: var(--yellow); color: var(--yellow); }

h2 {
  font-size: 1.6rem; font-weight: 700;
  background: linear-gradient(135deg, var(--text) 0%, var(--muted2) 100%);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}
.subtitle { color: var(--muted); font-size: 0.9rem; margin-top: 0.3rem; }

/* ─── CARDS ────────────────────────────────── */
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.5rem;
}
.card:hover { border-color: var(--border2); }

.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 1.5rem; }
.grid-3 { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 1.5rem; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1.2rem; }

/* ─── HERO ─────────────────────────────────── */
#hero {
  min-height: 100vh;
  display: flex; flex-direction: column; justify-content: center;
  position: relative; overflow: hidden;
}
#hero::before {
  content: '';
  position: absolute; top: -200px; left: 50%; transform: translateX(-50%);
  width: 800px; height: 800px;
  background: radial-gradient(ellipse at center, rgba(59,158,255,0.07) 0%, transparent 70%);
  pointer-events: none;
}
#hero::after {
  content: '';
  position: absolute; bottom: -100px; right: -100px;
  width: 500px; height: 500px;
  background: radial-gradient(ellipse at center, rgba(16,217,140,0.05) 0%, transparent 70%);
  pointer-events: none;
}
.hero-tag {
  display: inline-flex; align-items: center; gap: 0.5rem;
  background: var(--blue-dim); border: 1px solid var(--blue);
  border-radius: 100px; padding: 0.4rem 1rem;
  font-size: 0.78rem; color: var(--blue); font-weight: 600;
  margin-bottom: 2rem; width: fit-content;
}
.hero-tag::before { content: '●'; font-size: 0.5rem; animation: pulse 2s infinite; }
@keyframes pulse { 0%,100%{opacity:1} 50%{opacity:0.3} }

h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 900; line-height: 1.15;
  margin-bottom: 1.5rem;
}
h1 .accent { color: var(--blue); }
h1 .accent-green { color: var(--green); }

.hero-desc { font-size: 1.05rem; color: var(--muted2); max-width: 680px; margin-bottom: 3rem; }

.metric-chips {
  display: flex; flex-wrap: wrap; gap: 1rem; margin-bottom: 3rem;
}
.chip {
  background: var(--card); border: 1px solid var(--border);
  border-radius: 10px; padding: 1rem 1.5rem;
  display: flex; flex-direction: column; gap: 0.2rem;
}
.chip-val { font-size: 1.8rem; font-weight: 900; font-family: 'JetBrains Mono', monospace; }
.chip-label { font-size: 0.9rem; color: var(--muted); font-weight: 600; letter-spacing: 0.05em; text-transform: uppercase; }
.chip.blue .chip-val { color: var(--blue); }
.chip.green .chip-val { color: var(--green); }
.chip.purple .chip-val { color: var(--purple); }
.chip.orange .chip-val { color: var(--orange); }

/* ─── PIPELINE FLOW ────────────────────────── */
.pipeline-flow {
  display: flex; align-items: stretch; gap: 0;
  overflow-x: auto; padding: 1rem 0;
}
.pipe-node {
  flex: 1; min-width: 160px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.4rem 1rem;
  text-align: center;
  position: relative;
  transition: all 0.3s;
  display: flex;
  flex-direction: column;
  align-items: center;
}
.pipe-node:hover { border-color: var(--border2); transform: translateY(-2px); }
.pipe-node .icon { font-size: 2rem; margin-bottom: 0.6rem; }
.pipe-node h4 { font-size: 1.05rem; font-weight: 700; color: var(--text); margin-bottom: 0.4rem; }
.pipe-node p { font-size: 0.95rem; color: var(--muted); line-height: 1.5; margin-bottom: 1rem; }
.pipe-node .rmse-badge {
  margin-top: auto;
  background: var(--card2); border: 1px solid var(--border);
  border-radius: 6px; padding: 0.3rem 0.5rem;
  font-size: 0.85rem; font-family: 'JetBrains Mono', monospace;
  font-weight: 700;
  width: 100%;
}
.pipe-arrow {
  display: flex; align-items: center; justify-content: center;
  padding: 0 0.6rem; color: var(--muted); font-size: 1.2rem; flex-shrink: 0;
}
.pipe-node.highlight { border-color: var(--green); box-shadow: var(--glow-green); }
.pipe-node.highlight .rmse-badge { border-color: var(--green); color: var(--green); }

/* ─── FORMULA BOX ──────────────────────────── */
.formula-box {
  background: var(--card2);
  border: 1px solid var(--border2);
  border-radius: 10px;
  padding: 1.5rem 2rem;
  font-family: 'JetBrains Mono', monospace;
  font-size: 1.05rem;
  line-height: 2;
  overflow-x: auto;
}
.formula-box .f-label { color: var(--muted); font-size: 0.9rem; text-transform: uppercase; letter-spacing: 0.08em; margin-bottom: 0.5rem; display: block; font-weight: 700; }
.formula-box .f-male { color: var(--blue); }
.formula-box .f-female { color: var(--pink); }
.formula-box .f-var { color: var(--cyan); }
.formula-box .f-param { color: var(--yellow); }
.formula-box .f-op { color: var(--muted2); }

.param-table {
  width: 100%; border-collapse: collapse;
  font-size: 0.95rem;
}
.param-table th {
  background: var(--card2); color: var(--muted);
  font-size: 0.9rem; text-transform: uppercase; letter-spacing: 0.08em;
  padding: 0.6rem 1rem; border-bottom: 1px solid var(--border); font-weight: 700;
  text-align: left;
}
.param-table td {
  padding: 0.55rem 1rem; border-bottom: 1px solid var(--border);
  font-family: 'JetBrains Mono', monospace;
}
.param-table tr:last-child td { border-bottom: none; }
.param-table .val-m { color: var(--blue); }
.param-table .val-f { color: var(--pink); }
.param-table .desc { color: var(--muted2); font-family: 'Noto Sans KR', sans-serif; font-size: 0.9rem; }

/* ─── FEATURE CARDS ────────────────────────── */
.feature-group {
  border: 1px solid var(--border);
  border-radius: 10px; overflow: hidden; margin-bottom: 1rem;
}
.feature-group-header {
  background: var(--card2); padding: 0.6rem 1rem;
  font-size: 0.9rem; font-weight: 700; text-transform: uppercase;
  letter-spacing: 0.08em; display: flex; align-items: center; gap: 0.5rem;
}
.feature-tags {
  display: flex; flex-wrap: wrap; gap: 0.5rem; padding: 0.8rem 1rem;
  background: var(--card);
}
.ftag {
  background: var(--card2); border: 1px solid var(--border);
  border-radius: 6px; padding: 0.25rem 0.6rem;
  font-size: 0.95rem; font-family: 'JetBrains Mono', monospace;
  color: var(--muted2); font-weight: 600;
}
.ftag.key { border-color: var(--orange); color: var(--orange); background: var(--orange-dim); }
.ftag.blue { border-color: var(--blue); color: var(--blue); background: var(--blue-dim); }

/* ─── MODEL CARDS ──────────────────────────── */
.model-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px; padding: 1.3rem;
  transition: all 0.3s;
}
.model-card:hover { transform: translateY(-3px); }
.model-card .model-icon { font-size: 1.8rem; margin-bottom: 0.6rem; }
.model-card h4 { font-size: 1rem; font-weight: 700; margin-bottom: 0.3rem; }
.model-card .model-rmse {
  font-size: 1.4rem; font-weight: 900;
  font-family: 'JetBrains Mono', monospace; margin: 0.5rem 0;
}
.model-card .model-params { font-size: 0.9rem; color: var(--muted); line-height: 1.7; font-weight: 500; }
.model-card.et { border-color: var(--blue); }
.model-card.et .model-rmse { color: var(--blue); }
.model-card.xgb { border-color: var(--orange); }
.model-card.xgb .model-rmse { color: var(--orange); }
.model-card.lgb { border-color: var(--green); }
.model-card.lgb .model-rmse { color: var(--green); }
.model-card.cat { border-color: var(--purple); }
.model-card.cat .model-rmse { color: var(--purple); }

/* ─── ENSEMBLE WEIGHTS ─────────────────────── */
.weight-bar-wrap {
  margin-bottom: 1rem;
}
.weight-bar-label {
  display: flex; justify-content: space-between; align-items: center;
  font-size: 1rem; margin-bottom: 0.4rem; font-weight: 600;
}
.weight-bar-track {
  height: 10px; background: var(--card2); border-radius: 100px; overflow: hidden;
}
.weight-bar-fill {
  height: 100%; border-radius: 100px;
  transition: width 1s ease;
}

/* ─── INSIGHT CARDS ────────────────────────── */
.insight-card {
  background: var(--card);
  border-left: 3px solid var(--blue);
  border-top: 1px solid var(--border);
  border-right: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  border-radius: 0 10px 10px 0;
  padding: 1.2rem 1.4rem;
}
.insight-card.orange { border-left-color: var(--orange); }
.insight-card.green { border-left-color: var(--green); }
.insight-card.purple { border-left-color: var(--purple); }
.insight-card h4 { font-size: 1.05rem; font-weight: 700; margin-bottom: 0.4rem; }
.insight-card p { font-size: 0.95rem; color: var(--muted2); line-height: 1.6; }

/* ─── FINAL METRICS ────────────────────────── */
.final-metric {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 16px; padding: 2rem;
  text-align: center;
  position: relative; overflow: hidden;
}
.final-metric::before {
  content: '';
  position: absolute; inset: 0;
  background: radial-gradient(ellipse at 50% 0%, rgba(16,217,140,0.08) 0%, transparent 60%);
  pointer-events: none;
}
.final-metric .fm-val {
  font-size: 3.5rem; font-weight: 900;
  font-family: 'JetBrains Mono', monospace;
  color: var(--green); line-height: 1;
  margin-bottom: 0.5rem;
}
.final-metric .fm-label {
  font-size: 1.05rem; color: var(--muted);
  text-transform: uppercase; letter-spacing: 0.1em; font-weight: 700;
}
.final-metric .fm-sub {
  font-size: 0.95rem; color: var(--muted); margin-top: 0.6rem;
}

/* ─── CANVAS ───────────────────────────────── */
.chart-wrap {
  position: relative;
  background: var(--card); border: 1px solid var(--border); border-radius: 12px;
  padding: 1.2rem;
}
.chart-title {
  font-size: 1rem; font-weight: 700; color: var(--muted2);
  text-transform: uppercase; letter-spacing: 0.06em; margin-bottom: 1rem;
}

/* ─── COMPARISON TABLE ─────────────────────── */
.compare-table { width: 100%; border-collapse: collapse; font-size: 0.95rem; }
.compare-table th {
  background: var(--card2); color: var(--muted); font-size: 0.9rem;
  text-transform: uppercase; letter-spacing: 0.08em;
  padding: 0.7rem 1.2rem; border-bottom: 1px solid var(--border);
  font-weight: 700; text-align: left;
}
.compare-table td {
  padding: 0.65rem 1.2rem; border-bottom: 1px solid var(--border);
}
.compare-table tr:last-child td { border-bottom: none; }
.compare-table .highlight-row td { background: rgba(16,217,140,0.05); }
.compare-table .mono { font-family: 'JetBrains Mono', monospace; }
.badge-sm {
  display: inline-block;
  border-radius: 4px; padding: 0.15rem 0.5rem;
  font-size: 0.85rem; font-weight: 700; font-family: 'JetBrains Mono', monospace;
}
.badge-sm.green { background: var(--green-dim); color: var(--green); border: 1px solid var(--green); }
.badge-sm.blue { background: var(--blue-dim); color: var(--blue); border: 1px solid var(--blue); }
.badge-sm.red { background: var(--red-dim); color: var(--red); border: 1px solid var(--red); }

/* ─── FP FRAC VIZ ──────────────────────────── */
.frac-vis {
  background: var(--card2); border: 1px solid var(--border);
  border-radius: 10px; padding: 1.5rem;
}
.frac-ruler {
  position: relative; height: 40px; background: linear-gradient(90deg, #1a3a5c, #3B9EFF, #10D98C, #FF8C42, #FF4D6D);
  border-radius: 8px; margin: 1.5rem 0 0.5rem;
  display: flex; align-items: center;
}
.frac-tick {
  position: absolute; top: -20px;
  font-size: 0.85rem; color: var(--muted);
  font-family: 'JetBrains Mono', monospace;
  transform: translateX(-50%); font-weight: 700;
}
.frac-label-bot {
  position: absolute; bottom: -20px;
  font-size: 0.85rem; color: var(--muted2);
  transform: translateX(-50%); white-space: nowrap; font-weight: 600;
}
.frac-zone {
  position: absolute; top: 0; bottom: 0;
  display: flex; align-items: center; justify-content: center;
  font-size: 0.8rem; font-weight: 700; color: white;
  border-radius: 8px;
}

/* ─── CODE BLOCK ───────────────────────────── */
.code-block {
  background: #0a0e1a; border: 1px solid var(--border);
  border-radius: 10px; padding: 1.2rem 1.5rem;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.95rem; line-height: 1.9;
  overflow-x: auto;
}
.code-block .c-comment { color: #4a5568; }
.code-block .c-key { color: var(--purple); }
.code-block .c-str { color: var(--green); }
.code-block .c-fn { color: var(--blue); }
.code-block .c-num { color: var(--orange); }
.code-block .c-var { color: var(--cyan); }
.code-block .c-op { color: var(--muted2); }

/* ─── FOOTER ───────────────────────────────── */
footer {
  background: var(--card); border-top: 1px solid var(--border);
  padding: 3rem 2rem; text-align: center;
  color: var(--muted); font-size: 0.9rem;
}

/* ─── ANIMATIONS ────────────────────────────── */
.fade-in {
  opacity: 0;
  transform: translateY(30px) scale(0.95);
  transition: opacity 1.2s cubic-bezier(0.16, 1, 0.3, 1), 
              transform 1.2s cubic-bezier(0.16, 1, 0.3, 1);
  will-change: transform, opacity;
}
.fade-in.visible { opacity: 1; transform: translateY(0) scale(1); }
.reveal-up { opacity: 0; transform: translateY(60px); transition: all 1.4s cubic-bezier(0.19, 1, 0.22, 1); }
.reveal-up.visible { opacity: 1; transform: translateY(0); }
.scale-in { opacity: 0; transform: scale(0.8); transition: all 1.2s cubic-bezier(0.34, 1.56, 0.64, 1); }
.scale-in.visible { opacity: 1; transform: scale(1); }
.delay-1 { transition-delay: 0.1s; }
.delay-2 { transition-delay: 0.2s; }
.delay-3 { transition-delay: 0.3s; }
.delay-4 { transition-delay: 0.4s; }

/* ─── MOBILE OPTIMIZATION ──────────────────── */
@media (max-width: 768px) {
  nav { padding: 0.5rem; height: auto; flex-wrap: wrap; justify-content: center; }
  nav .logo { width: 100%; text-align: center; margin-bottom: 0.3rem; font-size: 0.75rem; }
  nav a { font-size: 0.65rem; padding: 0.4rem; }

  .page { padding: 100px 0.8rem 40px; }
  
  h1 { font-size: 1.6rem; text-align: center; letter-spacing: -0.02em; }
  .hero-desc { font-size: 0.85rem; text-align: center; padding: 0 0.5rem; margin-bottom: 2rem; }
  .hero-tag { align-self: center; font-size: 0.65rem; padding: 0.6rem; line-height: 1.4; border-radius: 8px; margin: 0 auto 1.5rem; text-align: center; }
  
  .metric-chips { gap: 0.6rem; justify-content: center; }
  .chip { flex: 1 1 calc(50% - 0.6rem); padding: 0.7rem; }
  .chip-val { font-size: 1.2rem; }
  .chip-label { font-size: 0.7rem; }

  .grid-2, .grid-3, .grid-4 { 
    grid-template-columns: 1fr; 
    gap: 1rem; 
  }
  
  /* Table Responsiveness */
  .card { padding: 1rem; overflow: hidden; }
  .compare-table, .param-table {
    display: block;
    width: 100%;
    overflow-x: auto;
    white-space: nowrap;
    -webkit-overflow-scrolling: touch;
  }
  
  .compare-table th, .compare-table td,
  .param-table th, .param-table td {
    padding: 0.6rem 0.8rem;
    font-size: 0.8rem;
  }
  .param-table .desc { min-width: 120px; white-space: normal; }

  /* Chart & Canvas Styling for Mobile */
  .chart-wrap { padding: 0.8rem; display: flex; flex-direction: column; }
  .chart-wrap canvas { width: 100% !important; height: auto !important; }

  .pipeline-flow { flex-direction: column; align-items: center; gap: 1rem; }
  .pipe-arrow { transform: rotate(90deg); padding: 0.2rem 0; font-size: 1rem; }
  .pipe-node { width: 100%; max-width: none; padding: 1rem; }

  .formula-box { font-size: 0.75rem; padding: 0.8rem; line-height: 1.8; }
  .section-header { flex-direction: column; align-items: center; text-align: center; margin-bottom: 1.5rem; }
  h2 { font-size: 1.2rem; }

  .final-metric { padding: 1.2rem 0.5rem; }
  .final-metric .fm-val { font-size: 1.8rem; }
}