/* Base Theme */
:root {
  --bg: #0a0f17;
  --bg-alt: #111827;
  --bg-card: rgba(255, 255, 255, 0.04);
  --fg: #f8fafc;
  --muted: #a5b4fc;
  --accent: #6366f1;
  --accent-hover: #818cf8;
  --border: rgba(255, 255, 255, 0.08);
  --brand: linear-gradient(135deg, #6366f1 0%, #22d3ee 100%);
  --radius: 18px;
  --shadow: 0 24px 50px -24px rgba(15, 23, 42, 0.8);
  --transition: 220ms ease;
  --font-base: "Inter", "Segoe UI", system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
}

*, *::before, *::after { box-sizing: border-box; }

body {
  margin: 0;
  background: radial-gradient(circle at 20% 20%, rgba(99, 102, 241, 0.12), transparent 45%),
              radial-gradient(circle at 80% 0%, rgba(34, 211, 238, 0.12), transparent 50%),
              var(--bg);
  color: var(--fg);
  font-family: var(--font-base);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
a:hover, a:focus { color: var(--accent-hover); }

.site-header {
  position: sticky; top: 0; z-index: 100;
  display: flex; align-items: center; justify-content: space-between;
  padding: 1.2rem clamp(1.5rem, 3vw, 3rem);
  background: rgba(10, 15, 23, 0.8);
  backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--border);
}

.brand__mark {
  font-weight: 700; font-size: 1.05rem; letter-spacing: 0.03em;
  background: var(--brand); -webkit-background-clip: text; color: transparent;
}

.site-nav { display: flex; gap: 1.5rem; }
.site-nav a { font-size: 0.95rem; letter-spacing: 0.01em; position: relative; }
.site-nav a[aria-current="page"]::after, .site-nav a:hover::after {
  content: ""; position: absolute; left: 0; bottom: -0.4rem; width: 100%; height: 2px;
  background: var(--accent); border-radius: 999px;
}

.nav-toggle { display: none; background: transparent; border: 0; cursor: pointer; padding: 0.35rem; }
.nav-toggle span { display: block; width: 22px; height: 2px; background: var(--fg); margin-block: 4px; transition: var(--transition); }

.hero {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: clamp(2rem, 4vw, 4rem);
  padding: clamp(3rem, 6vw, 6rem) clamp(1.5rem, 6vw, 6rem) clamp(2rem, 4vw, 4rem);
  align-items: start;
}

.hero__content .eyebrow { text-transform: uppercase; letter-spacing: 0.12em; font-size: 0.75rem; color: var(--muted); }
.hero__content h1 { font-size: clamp(2.1rem, 3.4vw, 3.6rem); line-height: 1.15; margin-block: 1rem; }
.lead { font-size: 1.05rem; color: rgba(248, 250, 252, 0.82); max-width: 36rem; }
.hero__cta { margin-top: 1.5rem; display: flex; gap: 1rem; flex-wrap: wrap; }

.button { display: inline-flex; align-items: center; justify-content: center; font-weight: 600; padding: 0.75rem 1.8rem; border-radius: 999px; border: 1px solid transparent; transition: var(--transition); }
.button.primary { background: var(--accent); color: #0b1120; }
.button.primary:hover { background: var(--accent-hover); }
.button.ghost { border-color: var(--border); color: var(--fg); }
.button.ghost:hover { border-color: var(--accent); color: var(--accent-hover); }

.hero__stats { display: grid; gap: 1rem; }
.stat { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 1.5rem; box-shadow: var(--shadow); }
.stat__value { font-size: 2.4rem; font-weight: 700; display: block; margin-bottom: 0.35rem; }

.section { padding: clamp(3rem, 5vw, 5rem) clamp(1.5rem, 6vw, 6rem); }
.section.alt { background: rgba(15, 23, 42, 0.56); border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }
.section__header { max-width: 48rem; margin-bottom: 2.2rem; }
.section__header h2 { font-size: clamp(1.75rem, 2.6vw, 2.4rem); margin-bottom: 0.75rem; }

.card-grid { display: grid; gap: 1.8rem; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); }
.card { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 1.6rem; box-shadow: var(--shadow); transition: transform var(--transition); }
.card:hover { transform: translateY(-6px); }
.card__link { font-weight: 600; color: var(--accent); margin-top: 1rem; display: inline-flex; gap: 0.35rem; }

.signature-grid { display: grid; gap: 1.5rem; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); }
.signature-card { padding: 1.6rem; border-radius: var(--radius); background: rgba(12, 74, 110, 0.15); border: 1px solid rgba(14, 116, 144, 0.3); }

.page { padding-bottom: clamp(4rem, 6vw, 6rem); }
.page-header { padding: clamp(4rem, 6vw, 6rem) clamp(1.5rem, 6vw, 6rem) clamp(2rem, 3vw, 3rem); max-width: 60rem; }

.program { padding: clamp(2.5rem, 4vw, 4rem) clamp(1.5rem, 6vw, 6rem); border-bottom: 1px solid var(--border); }
.program:last-of-type { border-bottom: none; }
.program__header h2 { margin-bottom: 0.35rem; }
.program__tagline { color: var(--muted); font-size: 1rem; letter-spacing: 0.01em; }
.program__body { display: grid; gap: 2.2rem; margin-top: 1.5rem; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.program__summary { font-size: 1.05rem; color: rgba(248, 250, 252, 0.86); }
.program__details h3 { margin-top: 0; margin-bottom: 0.75rem; }

.metrics-list { list-style: none; padding: 0; margin: 0 0 1.5rem 0; display: grid; gap: 0.6rem; }
.metrics-list li::before { content: "⟢"; color: var(--accent); margin-right: 0.75rem; }

.table-wrapper { border-radius: var(--radius); overflow-x: auto; border: 1px solid var(--border); background: rgba(12, 18, 30, 0.7); box-shadow: var(--shadow); }
.papers-table { width: 100%; border-collapse: collapse; min-width: 680px; }
.papers-table th, .papers-table td { padding: 1.1rem 1.25rem; text-align: left; border-bottom: 1px solid rgba(148, 163, 184, 0.15); }
.papers-table th { background: rgba(15, 23, 42, 0.9); font-weight: 600; color: var(--muted); text-transform: uppercase; font-size: 0.75rem; letter-spacing: 0.1em; }
.papers-table tr:last-child td { border-bottom: none; }

.split { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 2.8rem; align-items: start; }

.site-footer { padding: 2rem clamp(1.5rem, 6vw, 6rem); text-align: center; font-size: 0.85rem; color: rgba(248, 250, 252, 0.6); border-top: 1px solid var(--border); background: rgba(10, 15, 23, 0.85); }

@media (max-width: 850px) {
  .site-nav { position: fixed; inset: 0 0 auto auto; top: 72px; right: clamp(1rem, 4vw, 2rem); padding: 1.5rem; flex-direction: column; align-items: flex-start; background: rgba(10, 15, 23, 0.96); border: 1px solid var(--border); border-radius: var(--radius); transform: scale(0.9); opacity: 0; pointer-events: none; transition: var(--transition); }
  .site-nav.is-open { opacity: 1; transform: scale(1); pointer-events: auto; }
  .nav-toggle { display: inline-flex; flex-direction: column; gap: 4px; }
  .nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
  .nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
  .nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }
}

@media (max-width: 600px) {
  .hero { padding-top: 3.5rem; }
  .hero__stats { grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); }
}

/* Paper pages */
.paper-hero {
  display: grid;
  grid-template-columns: 1.2fr .8fr;
  gap: clamp(1.5rem, 3vw, 3rem);
  align-items: center;
  padding: clamp(3rem, 6vw, 6rem) clamp(1.5rem, 6vw, 6rem) clamp(2rem, 3vw, 3rem);
}

.paper-hero__meta {
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 0.8rem;
}

.paper-visual {
  width: 100%;
  max-width: 640px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  background: var(--bg-card);
}

.paper-section {
  padding: clamp(2rem, 5vw, 4rem) clamp(1.5rem, 6vw, 6rem);
  border-top: 1px solid var(--border);
}

.cta-row { display: flex; gap: 1rem; flex-wrap: wrap; align-items: center; }
.muted { color: rgba(248, 250, 252, 0.75); }

/* KPI grid and equation blocks */
.kpi-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: 1rem; }
.kpi { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 1.25rem; text-align: center; box-shadow: var(--shadow); }
.kpi__value { font-size: 1.8rem; font-weight: 700; margin-bottom: 0.2rem; }
.kpi__label { color: var(--muted); font-size: 0.9rem; }

.eqn { background: rgba(12, 18, 30, 0.55); border: 1px solid var(--border); border-radius: var(--radius); padding: 1.2rem 1.4rem; box-shadow: var(--shadow); }
.eqn p { margin: 0.65rem 0; }

.figure { display: grid; gap: 0.75rem; justify-items: start; }
.figure img { max-width: 100%; height: auto; border-radius: var(--radius); border: 1px solid var(--border); box-shadow: var(--shadow); }
.figure figcaption { color: var(--muted); font-size: 0.9rem; }

/* Utilities */
.grid-2 { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 1.4rem; }