:root {
  --bg: #0a0a0f;
  --bg-elevated: #13131a;
  --bg-card: #1a1a24;
  --fg: #e8e8ed;
  --fg-muted: #9898a8;
  --accent: #00e599;
  --accent-dim: #00b877;
  --accent-glow: rgba(0, 229, 153, 0.15);
  --border: #2a2a36;
  --radius: 12px;
  --font-display: 'Space Grotesk', sans-serif;
  --font-body: 'DM Sans', sans-serif;
}

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

body {
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-body);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3 {
  font-family: var(--font-display);
  font-weight: 700;
  line-height: 1.1;
}

/* Hero */
.hero {
  min-height: 90vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 80px 24px;
  background: radial-gradient(ellipse at 50% 0%, var(--accent-glow) 0%, transparent 60%), var(--bg);
}

.hero-inner {
  max-width: 800px;
  text-align: center;
}

.hero-badge {
  display: inline-block;
  padding: 8px 16px;
  background: var(--accent-glow);
  border: 1px solid var(--accent-dim);
  border-radius: 100px;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--accent);
  margin-bottom: 32px;
  letter-spacing: 0.02em;
}

.hero h1 {
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  margin-bottom: 24px;
  color: var(--fg);
}

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

.lede {
  font-size: 1.2rem;
  color: var(--fg-muted);
  max-width: 600px;
  margin: 0 auto 48px;
}

.hero-stats {
  display: flex;
  gap: 40px;
  justify-content: center;
  flex-wrap: wrap;
}

.stat {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.stat-number {
  font-family: var(--font-display);
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--accent);
}

.stat-label {
  font-size: 0.85rem;
  color: var(--fg-muted);
  max-width: 140px;
  text-align: center;
}

/* Problem */
.problem {
  padding: 120px 24px;
  background: var(--bg-elevated);
}

.problem-inner {
  max-width: 1000px;
  margin: 0 auto;
}

.problem h2 {
  font-size: clamp(2rem, 4vw, 3rem);
  text-align: center;
  margin-bottom: 16px;
}

.problem-intro {
  text-align: center;
  color: var(--fg-muted);
  font-size: 1.1rem;
  margin-bottom: 60px;
}

.problem-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.problem-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
}

.problem-icon {
  font-size: 2rem;
  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;
}

/* How */
.how {
  padding: 120px 24px;
}

.how-inner {
  max-width: 800px;
  margin: 0 auto;
}

.how h2 {
  font-size: clamp(2rem, 4vw, 3rem);
  text-align: center;
  margin-bottom: 16px;
}

.how-intro {
  text-align: center;
  color: var(--fg-muted);
  font-size: 1.1rem;
  margin-bottom: 60px;
}

.how-steps {
  display: flex;
  flex-direction: column;
  gap: 40px;
}

.step {
  display: flex;
  gap: 24px;
  align-items: flex-start;
}

.step-number {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--accent);
  min-width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--accent-glow);
  border-radius: 12px;
  flex-shrink: 0;
}

.step-content h3 {
  font-size: 1.1rem;
  margin-bottom: 8px;
}

.step-content p {
  color: var(--fg-muted);
  font-size: 0.95rem;
}

/* Niches */
.niches {
  padding: 120px 24px;
  background: var(--bg-elevated);
}

.niches-inner {
  max-width: 800px;
  margin: 0 auto;
  text-align: center;
}

.niches h2 {
  font-size: clamp(1.8rem, 3.5vw, 2.5rem);
  margin-bottom: 40px;
}

.niches-grid {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
  margin-bottom: 48px;
}

.niche-tag {
  padding: 10px 20px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 100px;
  font-size: 0.9rem;
  color: var(--fg);
  font-weight: 500;
}

.niches-math {
  text-align: left;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
}

.math-example {
  color: var(--fg-muted);
  font-size: 1.05rem;
  margin-bottom: 12px;
}

.math-example:last-child {
  margin-bottom: 0;
  color: var(--accent);
  font-weight: 500;
}

.math-example strong {
  color: var(--fg);
}

/* Closing */
.closing {
  padding: 120px 24px;
  text-align: center;
}

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

.closing h2 {
  font-size: clamp(2rem, 4vw, 3rem);
  margin-bottom: 24px;
}

.closing-text {
  color: var(--fg-muted);
  font-size: 1.1rem;
  margin-bottom: 32px;
}

.closing-tagline {
  font-family: var(--font-display);
  font-size: 1.3rem;
  font-weight: 600;
  color: var(--accent);
}

/* Footer */
.site-footer {
  padding: 48px 24px;
  border-top: 1px solid var(--border);
  text-align: center;
}

.footer-brand {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.1rem;
  margin-bottom: 4px;
}

.footer-sub {
  color: var(--fg-muted);
  font-size: 0.85rem;
}

/* CTA Buttons */
.hero-ctas {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 48px;
}

.btn-primary {
  display: inline-block;
  padding: 14px 28px;
  background: var(--accent);
  color: #0a0a0f;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  border-radius: 8px;
  transition: background 0.2s ease, transform 0.15s ease, box-shadow 0.2s ease;
  box-shadow: 0 0 20px rgba(0,229,153,0.25);
}

.btn-primary:hover {
  background: var(--accent-dim);
  transform: translateY(-1px);
  box-shadow: 0 4px 24px rgba(0,229,153,0.35);
}

.btn-secondary {
  display: inline-block;
  padding: 14px 28px;
  background: transparent;
  color: var(--fg);
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  border: 1px solid var(--border);
  border-radius: 8px;
  transition: border-color 0.2s ease, color 0.2s ease, transform 0.15s ease;
}

.btn-secondary:hover {
  border-color: var(--accent);
  color: var(--accent);
  transform: translateY(-1px);
}

.btn-ghost {
  display: inline-block;
  padding: 14px 24px;
  background: transparent;
  color: var(--fg-muted);
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 0.9rem;
  text-decoration: none;
  border-radius: 8px;
  transition: color 0.2s ease;
}

.btn-ghost:hover {
  color: var(--fg);
}

/* Mobile */
@media (max-width: 640px) {
  .hero {
    min-height: 80vh;
    padding: 60px 20px;
  }

  .hero-stats {
    gap: 24px;
  }

  .stat-number {
    font-size: 2rem;
  }

  .step {
    flex-direction: column;
    gap: 12px;
  }

  .problem, .how, .niches, .closing {
    padding: 80px 20px;
  }
}