:root {
  --bg-deep: #0c0a09;
  --bg-surface: #1c1917;
  --bg-card: #292524;
  --fg: #fafaf9;
  --fg-muted: #a8a29e;
  --fg-subtle: #78716c;
  --accent: #f59e0b;
  --accent-soft: #fbbf24;
  --accent-glow: rgba(245, 158, 11, 0.15);
  --radius: 12px;
  --max-w: 1100px;
}

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

body {
  background: var(--bg-deep);
  color: var(--fg);
  font-family: 'DM Sans', sans-serif;
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3 {
  font-family: 'Syne', sans-serif;
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.02em;
}

/* HERO */
.hero {
  padding: 100px 24px 60px;
  text-align: center;
  background: linear-gradient(180deg, var(--bg-deep) 0%, #1a1510 50%, var(--bg-deep) 100%);
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -200px;
  left: 50%;
  transform: translateX(-50%);
  width: 800px;
  height: 800px;
  background: radial-gradient(circle, var(--accent-glow) 0%, transparent 70%);
  pointer-events: none;
}

.hero-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  position: relative;
  z-index: 1;
}

.hero-badge {
  display: inline-block;
  font-size: 13px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--accent);
  border: 1px solid rgba(245, 158, 11, 0.3);
  padding: 6px 18px;
  border-radius: 100px;
  margin-bottom: 32px;
}

.hero h1 {
  font-size: clamp(2.8rem, 6vw, 4.5rem);
  font-weight: 800;
  margin-bottom: 24px;
  color: var(--fg);
}

.hero h1 .accent {
  color: var(--accent);
  position: relative;
}

.hero-sub {
  font-size: 1.15rem;
  color: var(--fg-muted);
  max-width: 620px;
  margin: 0 auto;
  line-height: 1.7;
}

.hero-stat-row {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 40px;
  margin-top: 56px;
  padding-top: 40px;
  border-top: 1px solid rgba(168, 162, 158, 0.12);
  max-width: 700px;
  margin-left: auto;
  margin-right: auto;
  position: relative;
  z-index: 1;
}

.hero-stat { text-align: center; }
.stat-number {
  display: block;
  font-family: 'Syne', sans-serif;
  font-size: 2rem;
  font-weight: 800;
  color: var(--accent-soft);
}
.stat-label {
  display: block;
  font-size: 0.82rem;
  color: var(--fg-subtle);
  margin-top: 4px;
}
.hero-stat-divider {
  width: 1px;
  height: 40px;
  background: rgba(168, 162, 158, 0.15);
}

/* PROBLEM */
.problem {
  padding: 100px 24px;
  background: var(--bg-deep);
}

.problem-inner {
  max-width: var(--max-w);
  margin: 0 auto;
}

.problem-label, .features-label, .math-label {
  font-size: 13px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--accent);
  margin-bottom: 16px;
}

.problem h2, .features h2, .math h2 {
  font-size: clamp(1.8rem, 3.5vw, 2.6rem);
  margin-bottom: 48px;
  max-width: 680px;
}

.problem-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.problem-card {
  background: var(--bg-surface);
  border: 1px solid rgba(168, 162, 158, 0.08);
  border-radius: var(--radius);
  padding: 36px 28px;
  transition: border-color 0.2s;
}

.problem-card:hover {
  border-color: rgba(245, 158, 11, 0.2);
}

.problem-icon {
  font-family: 'Syne', sans-serif;
  font-weight: 800;
  font-size: 1.4rem;
  color: var(--accent);
  margin-bottom: 16px;
}

.problem-card h3 {
  font-size: 1.2rem;
  margin-bottom: 12px;
  color: var(--fg);
}

.problem-card p {
  color: var(--fg-muted);
  font-size: 0.95rem;
  line-height: 1.6;
}

/* FEATURES */
.features {
  padding: 100px 24px;
  background: var(--bg-surface);
}

.features-inner {
  max-width: var(--max-w);
  margin: 0 auto;
}

.features-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}

.feature-block {
  background: var(--bg-card);
  border: 1px solid rgba(168, 162, 158, 0.08);
  border-radius: var(--radius);
  padding: 36px 28px;
  transition: border-color 0.2s, transform 0.2s;
}

.feature-block:hover {
  border-color: rgba(245, 158, 11, 0.25);
  transform: translateY(-2px);
}

.feature-large {
  grid-column: 1 / -1;
  background: linear-gradient(135deg, var(--bg-card) 0%, #2a2015 100%);
  border-color: rgba(245, 158, 11, 0.15);
}

.feature-tag {
  display: inline-block;
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent);
  background: var(--accent-glow);
  padding: 4px 12px;
  border-radius: 6px;
  margin-bottom: 16px;
}

.feature-block h3 {
  font-size: 1.25rem;
  margin-bottom: 12px;
  color: var(--fg);
}

.feature-block p {
  color: var(--fg-muted);
  font-size: 0.95rem;
  line-height: 1.6;
}

/* MATH */
.math {
  padding: 100px 24px;
  background: var(--bg-deep);
}

.math-inner {
  max-width: 700px;
  margin: 0 auto;
}

.math-table {
  margin-top: 8px;
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid rgba(168, 162, 158, 0.1);
}

.math-row {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  padding: 18px 24px;
  border-bottom: 1px solid rgba(168, 162, 158, 0.06);
  font-size: 0.95rem;
}

.math-row:last-child { border-bottom: none; }

.math-header {
  background: var(--bg-surface);
  font-weight: 600;
  color: var(--fg-subtle);
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.math-highlight {
  background: var(--accent-glow);
  color: var(--accent-soft);
  font-weight: 600;
}

.math-badge {
  font-size: 10px;
  background: var(--accent);
  color: var(--bg-deep);
  padding: 2px 8px;
  border-radius: 100px;
  margin-left: 8px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.math-note {
  margin-top: 28px;
  color: var(--fg-muted);
  font-size: 0.95rem;
  font-style: italic;
}

/* CLOSING */
.closing {
  padding: 120px 24px;
  background: linear-gradient(180deg, var(--bg-deep) 0%, #1a1510 100%);
  text-align: center;
  position: relative;
}

.closing::before {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, var(--accent-glow) 0%, transparent 70%);
  pointer-events: none;
}

.closing-inner {
  max-width: 700px;
  margin: 0 auto;
  position: relative;
  z-index: 1;
}

.closing h2 {
  font-size: clamp(1.8rem, 3.5vw, 2.8rem);
  margin-bottom: 24px;
}

.closing p {
  color: var(--fg-muted);
  font-size: 1.05rem;
  line-height: 1.7;
  margin-bottom: 20px;
}

.closing-accent {
  color: var(--accent-soft) !important;
  font-weight: 600;
  font-size: 1.15rem !important;
}

/* FOOTER */
.site-footer {
  padding: 48px 24px;
  text-align: center;
  background: var(--bg-deep);
  border-top: 1px solid rgba(168, 162, 158, 0.08);
}

.footer-brand {
  font-family: 'Syne', sans-serif;
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--fg);
}

.footer-sub {
  font-size: 0.85rem;
  color: var(--fg-subtle);
  margin-top: 6px;
}

/* RESPONSIVE */
@media (max-width: 768px) {
  .problem-grid {
    grid-template-columns: 1fr;
  }
  .features-grid {
    grid-template-columns: 1fr;
  }
  .feature-large {
    grid-column: 1;
  }
  .hero-stat-row {
    flex-direction: column;
    gap: 24px;
  }
  .hero-stat-divider {
    width: 40px;
    height: 1px;
  }
  .hero {
    padding: 72px 20px 48px;
  }
  .math-row {
    font-size: 0.85rem;
    padding: 14px 16px;
  }
}

@media (max-width: 480px) {
  .hero h1 {
    font-size: 2.2rem;
  }
  .problem h2, .features h2, .math h2, .closing h2 {
    font-size: 1.6rem;
  }
}