:root {
  --bg: #f9f6f1;
  --bg-alt: #f0ebe3;
  --fg: #1a1a1a;
  --fg-muted: #6b6560;
  --accent: #c8773a;
  --accent-dark: #a85e28;
  --border: #e0d9cf;
}

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

html {
  scroll-behavior: smooth;
}

body {
  background: var(--bg);
  color: var(--fg);
  font-family: 'DM Sans', system-ui, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* Navigation */
.site-nav {
  padding: 20px 0;
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 40px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-family: 'Fraunces', serif;
  font-size: 20px;
  font-weight: 700;
  color: var(--fg);
  letter-spacing: -0.02em;
}

.nav-tagline {
  font-size: 13px;
  color: var(--fg-muted);
  letter-spacing: 0.01em;
}

/* Hero */
.hero {
  padding: 100px 0 80px;
}

.hero-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 40px;
}

.hero-label {
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 20px;
}

.hero-headline {
  font-family: 'Fraunces', serif;
  font-size: clamp(40px, 6vw, 72px);
  font-weight: 600;
  line-height: 1.08;
  letter-spacing: -0.03em;
  color: var(--fg);
  margin-bottom: 28px;
}

.hero-sub {
  font-size: 18px;
  color: var(--fg-muted);
  max-width: 540px;
  line-height: 1.65;
}

/* Proof */
.proof {
  padding: 48px 0;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  background: var(--bg-alt);
}

.proof-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 40px;
  display: flex;
  align-items: center;
  gap: 0;
}

.proof-stat {
  flex: 1;
  text-align: center;
  padding: 0 24px;
}

.proof-num {
  display: block;
  font-family: 'Fraunces', serif;
  font-size: 44px;
  font-weight: 700;
  color: var(--fg);
  letter-spacing: -0.03em;
  line-height: 1;
  margin-bottom: 6px;
}

.proof-label {
  font-size: 13px;
  color: var(--fg-muted);
  letter-spacing: 0.02em;
}

.proof-divider {
  width: 1px;
  height: 48px;
  background: var(--border);
}

/* Features */
.features {
  padding: 96px 0;
}

.features-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 40px;
}

.features-header {
  max-width: 600px;
  margin-bottom: 56px;
}

.features-title {
  font-family: 'Fraunces', serif;
  font-size: clamp(28px, 4vw, 42px);
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.15;
  color: var(--fg);
  margin-bottom: 16px;
}

.features-sub {
  font-size: 16px;
  color: var(--fg-muted);
  line-height: 1.65;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
}

.feature-card {
  background: var(--bg);
  padding: 36px 32px;
}

.feature-icon {
  color: var(--accent);
  margin-bottom: 16px;
  display: flex;
}

.feature-card h3 {
  font-family: 'Fraunces', serif;
  font-size: 18px;
  font-weight: 600;
  color: var(--fg);
  margin-bottom: 10px;
  letter-spacing: -0.01em;
}

.feature-card p {
  font-size: 14px;
  color: var(--fg-muted);
  line-height: 1.65;
}

/* Math */
.math-section {
  padding: 96px 0;
  background: var(--fg);
  color: #fff;
}

.math-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 40px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 80px;
  align-items: center;
}

.math-title {
  font-family: 'Fraunces', serif;
  font-size: clamp(26px, 3.5vw, 38px);
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.2;
  color: #fff;
  margin-bottom: 16px;
}

.math-body {
  font-size: 15px;
  color: rgba(255,255,255,0.55);
  line-height: 1.7;
}

.math-equation {
  display: flex;
  align-items: center;
  gap: 20px;
  flex-wrap: wrap;
}

.eq-block {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.eq-label {
  font-size: 12px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.4);
}

.eq-value {
  font-family: 'Fraunces', serif;
  font-size: 22px;
  font-weight: 600;
  color: rgba(255,255,255,0.85);
  letter-spacing: -0.02em;
}

.eq-highlight .eq-value {
  color: var(--accent);
}

.eq-highlight .eq-label {
  color: var(--accent);
  opacity: 0.7;
}

.eq-plus, .eq-equals {
  font-size: 24px;
  color: rgba(255,255,255,0.25);
  font-weight: 300;
  line-height: 1;
}

/* Closing */
.closing {
  padding: 96px 0;
  border-top: 1px solid var(--border);
}

.closing-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 40px;
}

.closing-headline {
  font-family: 'Fraunces', serif;
  font-size: clamp(32px, 5vw, 58px);
  font-weight: 600;
  letter-spacing: -0.03em;
  line-height: 1.1;
  color: var(--fg);
  margin-bottom: 24px;
}

.closing-sub {
  font-size: 17px;
  color: var(--fg-muted);
  max-width: 520px;
  line-height: 1.7;
}

/* Footer */
.site-footer {
  padding: 40px 0;
  border-top: 1px solid var(--border);
}

.footer-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 40px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.footer-logo {
  font-family: 'Fraunces', serif;
  font-size: 16px;
  font-weight: 700;
  color: var(--fg);
  letter-spacing: -0.02em;
}

.footer-desc {
  font-size: 13px;
  color: var(--fg-muted);
  margin-top: 4px;
}

.footer-links {
  font-size: 13px;
  color: var(--fg-muted);
}

/* Responsive */
@media (max-width: 768px) {
  .nav-inner { padding: 0 24px; }
  .hero-inner { padding: 0 24px; }
  .proof-inner { padding: 0 24px; flex-direction: column; gap: 32px; }
  .proof-divider { width: 48px; height: 1px; }
  .features-inner { padding: 0 24px; }
  .feature-grid { grid-template-columns: 1fr; }
  .math-inner { grid-template-columns: 1fr; gap: 48px; }
  .math-equation { justify-content: flex-start; }
  .closing-inner { padding: 0 24px; }
  .footer-inner { padding: 0 24px; flex-direction: column; gap: 12px; }
}

@media (max-width: 480px) {
  .hero { padding: 72px 0 60px; }
  .proof { padding: 40px 0; }
  .features { padding: 64px 0; }
  .math-section { padding: 64px 0; }
  .closing { padding: 64px 0; }
  .math-equation { gap: 12px; }
  .eq-value { font-size: 18px; }
}