:root {
  --bg: #0b0b0d;
  --fg: #e8e3d8;
  --accent: #e8a030;
  --accent-dim: #a8741f;
  --muted: #6b6560;
  --border: #1e1e20;
  --card-bg: #111114;
  --code-bg: #0f0f12;
  --serif: 'Instrument Serif', Georgia, serif;
  --sans: 'IBM Plex Sans', system-ui, sans-serif;
  --mono: 'IBM Plex Mono', monospace;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { font-size: 16px; scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--fg);
  font-family: var(--sans);
  font-weight: 400;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

/* ── Nav ── */
.nav {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  padding: 2rem 4rem;
  border-bottom: 1px solid var(--border);
}
.nav-brand {
  font-family: var(--serif);
  font-size: 1.4rem;
  color: var(--accent);
  letter-spacing: 0.02em;
}
.nav-tagline {
  font-size: 0.75rem;
  color: var(--muted);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  font-family: var(--mono);
}

/* ── Section Label ── */
.section-label {
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 1.5rem;
}

/* ── Hero ── */
.hero {
  padding: 6rem 4rem 5rem;
  border-bottom: 1px solid var(--border);
}
.hero-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 5rem;
  align-items: center;
  max-width: 1200px;
}
.hero-eyebrow {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 1.25rem;
}
.hero-headline {
  font-family: var(--serif);
  font-size: clamp(2.8rem, 5vw, 4.2rem);
  line-height: 1.08;
  color: var(--fg);
  margin-bottom: 1.75rem;
  font-style: italic;
}
.hero-sub {
  font-size: 1.05rem;
  color: #a09a90;
  line-height: 1.7;
  max-width: 480px;
}

/* World Model Diagram */
.hero-visual {
  display: flex;
  align-items: center;
  justify-content: center;
}
.world-model-diagram {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.75rem;
}
.wm-label {
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--muted);
  letter-spacing: 0.08em;
  text-align: center;
}
.wm-arrow { opacity: 0.7; }
.wm-core {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 1.25rem 1.75rem;
  text-align: center;
}
.wm-formula {
  font-family: var(--mono);
  font-size: 0.82rem;
  color: var(--accent);
  margin-bottom: 1rem;
  letter-spacing: 0.04em;
}
.wm-pills {
  display: flex;
  gap: 0.5rem;
  justify-content: center;
  flex-wrap: wrap;
}
.pill {
  font-family: var(--mono);
  font-size: 0.65rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--fg);
  border: 1px solid var(--border);
  border-radius: 2px;
  padding: 0.2rem 0.6rem;
}

/* ── Problem ── */
.problem { padding: 5rem 4rem; border-bottom: 1px solid var(--border); }
.problem-inner { max-width: 1100px; }
.problem-grid {
  display: flex;
  gap: 2rem;
  align-items: flex-start;
  margin: 2.5rem 0;
}
.problem-card { flex: 1; }
.problem-card-label {
  font-family: var(--mono);
  font-size: 0.65rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 0.5rem;
}
.problem-card-title {
  font-family: var(--serif);
  font-size: 2.2rem;
  color: var(--fg);
  margin-bottom: 1rem;
  font-style: italic;
}
.problem-card-desc { font-size: 0.9rem; color: #888; line-height: 1.65; }
.problem-card.stateless .problem-card-title { color: #555; }
.problem-card.mihawk .problem-card-title { color: var(--accent); }
.divider {
  display: flex;
  align-items: center;
  padding-top: 3.5rem;
  color: var(--muted);
  font-size: 1.4rem;
}
.problem-bottom {
  font-size: 0.9rem;
  color: var(--muted);
  border-top: 1px solid var(--border);
  padding-top: 1.5rem;
  max-width: 480px;
}

/* ── Approach ── */
.approach { padding: 5rem 4rem; border-bottom: 1px solid var(--border); }
.approach-inner { max-width: 1100px; }
.approach-headline {
  font-family: var(--serif);
  font-size: clamp(1.8rem, 3vw, 2.6rem);
  line-height: 1.15;
  margin-bottom: 4rem;
  font-style: italic;
}
.approach-steps { display: flex; flex-direction: column; gap: 0; }
.step {
  display: grid;
  grid-template-columns: 5rem 1fr;
  gap: 2rem;
  padding: 2.5rem 0;
  border-top: 1px solid var(--border);
}
.step:last-child { border-bottom: 1px solid var(--border); }
.step-num {
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--muted);
  padding-top: 0.25rem;
}
.step-title {
  font-family: var(--serif);
  font-size: 1.6rem;
  color: var(--fg);
  font-style: italic;
  margin-bottom: 0.25rem;
}
.step-desc {
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--accent);
  letter-spacing: 0.06em;
  margin-bottom: 1rem;
}
.step-body { font-size: 0.9rem; color: #888; line-height: 1.7; margin-bottom: 1.25rem; max-width: 560px; }
.step-tags { display: flex; gap: 0.5rem; flex-wrap: wrap; }
.tag {
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
  border: 1px solid var(--border);
  border-radius: 2px;
  padding: 0.15rem 0.5rem;
}

/* ── Deployments ── */
.deployments { padding: 5rem 4rem; border-bottom: 1px solid var(--border); }
.deployments-inner { max-width: 1100px; }
.deployments-headline {
  font-family: var(--serif);
  font-size: clamp(1.8rem, 3vw, 2.6rem);
  line-height: 1.15;
  margin-bottom: 1rem;
  font-style: italic;
}
.deployments-sub {
  font-size: 0.9rem;
  color: var(--muted);
  max-width: 500px;
  margin-bottom: 3rem;
  line-height: 1.7;
}
.deploy-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5px;
  background: var(--border);
  border: 1px solid var(--border);
}
.deploy-card {
  background: var(--card-bg);
  padding: 2.5rem 2rem;
}
.deploy-icon {
  margin-bottom: 1.5rem;
  opacity: 0.8;
}
.deploy-domain {
  font-family: var(--mono);
  font-size: 0.65rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 0.4rem;
}
.deploy-title {
  font-family: var(--serif);
  font-size: 1.35rem;
  color: var(--fg);
  font-style: italic;
  margin-bottom: 0.85rem;
}
.deploy-desc { font-size: 0.85rem; color: #888; line-height: 1.65; }

/* ── Research ── */
.research { padding: 5rem 4rem; border-bottom: 1px solid var(--border); }
.research-inner { max-width: 1100px; }
.research-headline {
  font-family: var(--serif);
  font-size: clamp(1.8rem, 3vw, 2.6rem);
  line-height: 1.15;
  margin-bottom: 1rem;
  font-style: italic;
}
.research-sub { font-size: 0.9rem; color: var(--muted); margin-bottom: 3rem; max-width: 460px; line-height: 1.7; }
.papers-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 1.5px; background: var(--border); border: 1px solid var(--border); }
.paper-card { background: var(--card-bg); padding: 2.5rem 2rem; }
.paper-tag {
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.75rem;
}
.paper-title {
  font-family: var(--mono);
  font-size: 1.1rem;
  font-weight: 500;
  color: var(--fg);
  margin-bottom: 0.75rem;
  letter-spacing: 0.04em;
}
.paper-desc { font-size: 0.82rem; color: #888; line-height: 1.55; margin-bottom: 1rem; }
.paper-result {
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--accent-dim);
  background: var(--code-bg);
  padding: 0.6rem 0.85rem;
  border-radius: 2px;
  margin-bottom: 1.25rem;
  letter-spacing: 0.02em;
}
.paper-link {
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--fg);
  text-decoration: none;
  letter-spacing: 0.05em;
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.15rem;
}
.paper-link:hover { color: var(--accent); border-color: var(--accent); }

/* ── Philosophy ── */
.philosophy { padding: 5rem 4rem; border-bottom: 1px solid var(--border); }
.philosophy-inner { max-width: 1100px; }
.philosophy-headline {
  font-family: var(--serif);
  font-size: clamp(2.2rem, 4vw, 3.4rem);
  line-height: 1.08;
  margin-bottom: 2rem;
  font-style: italic;
}
.philosophy-quote {
  font-family: var(--serif);
  font-size: 1.25rem;
  line-height: 1.55;
  color: var(--muted);
  max-width: 620px;
  margin-bottom: 3.5rem;
  font-style: italic;
  border-left: 2px solid var(--accent);
  padding-left: 1.5rem;
}
.principles-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 2.5rem; }
.principle-title {
  font-family: var(--mono);
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--fg);
  margin-bottom: 0.75rem;
  letter-spacing: 0.04em;
}
.principle-desc { font-size: 0.85rem; color: #888; line-height: 1.65; }

/* ── Closing ── */
.closing { padding: 7rem 4rem 6rem; border-bottom: 1px solid var(--border); }
.closing-inner { max-width: 1100px; }
.closing-headline {
  font-family: var(--serif);
  font-size: clamp(2.4rem, 4.5vw, 3.8rem);
  line-height: 1.08;
  margin-bottom: 1.5rem;
  font-style: italic;
}
.closing-sub {
  font-size: 1rem;
  color: var(--muted);
  max-width: 480px;
  line-height: 1.7;
  margin-bottom: 2.5rem;
}
.closing-contacts { display: flex; align-items: center; gap: 1.25rem; }
.contact-link {
  font-family: var(--mono);
  font-size: 0.85rem;
  color: var(--fg);
  text-decoration: none;
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.15rem;
}
.contact-link:hover { color: var(--accent); border-color: var(--accent); }
.contact-sep { color: var(--muted); }

/* ── Footer ── */
.footer { padding: 2rem 4rem; }
.footer-inner { display: flex; align-items: center; justify-content: space-between; }
.footer-brand {
  font-family: var(--serif);
  font-size: 1.1rem;
  color: var(--muted);
  font-style: italic;
}
.footer-copy { font-family: var(--mono); font-size: 0.7rem; color: #3a3a3c; letter-spacing: 0.08em; }

/* ── Responsive ── */
@media (max-width: 900px) {
  .nav { padding: 1.5rem 2rem; }
  .hero { padding: 4rem 2rem 3.5rem; }
  .hero-inner { grid-template-columns: 1fr; gap: 3rem; }
  .hero-visual { justify-content: flex-start; }
  .problem { padding: 4rem 2rem; }
  .problem-grid { flex-direction: column; gap: 1rem; }
  .divider { display: none; }
  .approach { padding: 4rem 2rem; }
  .deployments { padding: 4rem 2rem; }
  .deploy-grid { grid-template-columns: 1fr; }
  .research { padding: 4rem 2rem; }
  .papers-grid { grid-template-columns: 1fr; }
  .philosophy { padding: 4rem 2rem; }
  .principles-grid { grid-template-columns: 1fr; gap: 2rem; }
  .closing { padding: 5rem 2rem 4rem; }
  .footer { padding: 1.5rem 2rem; }
}

@media (max-width: 480px) {
  .nav { padding: 1.25rem 1.25rem; }
  .hero { padding: 3rem 1.25rem 2.5rem; }
  .problem, .approach, .deployments, .research, .philosophy, .closing { padding-left: 1.25rem; padding-right: 1.25rem; }
  .footer { padding: 1.25rem; }
  .footer-inner { flex-direction: column; gap: 0.5rem; align-items: flex-start; }
}