html,
body {
  margin: 0;
  padding: 0;
  background: #0b0b0c;
  color: #f0f0f2;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
}

main {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  text-align: center;
}

h1 {
  font-size: 3rem;
  margin-bottom: 0.75rem;
  font-weight: 600;
}

p {
  max-width: 520px;
  opacity: 0.85;
  line-height: 1.5;
}

.sub {
  opacity: 0.6;
  font-size: 0.9rem;
}

a {
  color: inherit;
  text-decoration: none;
  border-bottom: 1px solid rgba(255, 255, 255, 0.3);
}

/* Hero section */
.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: 2rem;
  box-sizing: border-box;
}

.kicker {
  text-transform: uppercase;
  letter-spacing: 0.2em;
  font-size: 0.8rem;
  font-weight: 700;
  margin-bottom: 1.5rem;
  opacity: 0.6;
}

.lede {
  font-size: 1.125rem;
  margin: 1.5rem auto 2rem;
  max-width: 640px;
}

.cta {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  justify-content: center;
  margin: 2rem 0;
}

.btn {
  padding: 0.875rem 1.75rem;
  border-radius: 4px;
  font-weight: 600;
  transition: all 0.2s ease;
}

.btn.primary {
  background: #f0f0f2;
  color: #0b0b0c;
  border: none;
}

.btn:not(.primary) {
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.2);
}

.fine {
  font-size: 0.75rem;
  opacity: 0.4;
  margin-top: 3rem;
}

/* Scroll narrative */
.story {
  overflow-y: scroll;
  scroll-snap-type: y mandatory;
  max-height: 500vh;
}

@media (prefers-reduced-motion: no-preference) {
  .story {
    scroll-behavior: smooth;
  }
}

.story-intro {
  min-height: 100vh;
  scroll-snap-align: start;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: 2rem;
  box-sizing: border-box;
}

.story-intro h2 {
  font-size: 2.5rem;
  margin-bottom: 1.5rem;
}

.panels {
  display: flex;
  flex-direction: column;
}

.panel {
  min-height: 100vh;
  scroll-snap-align: start;
  position: relative;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: 2rem;
  box-sizing: border-box;
  overflow: hidden;
}

.panel-overlay {
  position: absolute;
  inset: 0;
  opacity: 0.6;
}

.panel-content {
  position: relative;
  z-index: 1;
  max-width: 640px;
  text-align: left;
}

.panel-eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.15em;
  font-size: 0.75rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  opacity: 0.5;
}

.panel h3 {
  font-size: 2.5rem;
  margin: 0 0 1.25rem 0;
}

.panel p {
  font-size: 1.125rem;
  margin-bottom: 1.5rem;
}

.panel ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.panel li {
  padding: 0.75rem 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  position: relative;
  padding-left: 1.5rem;
}

.panel li::before {
  content: "→";
  position: absolute;
  left: 0;
  opacity: 0.5;
}

/* Stage backgrounds */
.panel[data-stage="record"] .panel-overlay {
  background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
}

.panel[data-stage="propose"] .panel-overlay {
  background: linear-gradient(135deg, #0f0c29 0%, #302b63 50%, #24243e 100%);
}

.panel[data-stage="replay"] .panel-overlay {
  background: linear-gradient(135deg, #1f1c2c 0%, #928dab 100%);
}

.panel[data-stage="validate"] .panel-overlay {
  background: linear-gradient(135deg, #0b0b0c 0%, #1a1a1d 50%, #2d132c 100%);
}

.panel[data-stage="integrate"] .panel-overlay {
  background: linear-gradient(135deg, #1e1e1e 0%, #2c3e50 100%);
}

/* Use cases */
.card {
  padding: 4rem 2rem;
  box-sizing: border-box;
}

.card h2 {
  font-size: 2rem;
  margin-bottom: 2rem;
}

.usecases {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  justify-content: center;
  max-width: 800px;
  margin: 0 auto 2rem;
}

.pill {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.15);
  padding: 0.75rem 1.25rem;
  border-radius: 2rem;
  font-size: 0.9rem;
}

.note {
  font-size: 0.9rem;
  opacity: 0.6;
  margin-top: 1rem;
}

/* Footer */
.footer {
  padding: 3rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  box-sizing: border-box;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
}

.footer-left {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.mark {
  width: 12px;
  height: 12px;
  background: #f0f0f2;
  border-radius: 2px;
}

.footer-title {
  font-weight: 600;
}

.footer-sub {
  font-size: 0.875rem;
  opacity: 0.6;
  margin-top: 0.25rem;
}

.footer-sub a {
  border-bottom: none;
}

/* Responsive */
@media (max-width: 768px) {
  h1 {
    font-size: 2.25rem;
  }

  .lede {
    font-size: 1rem;
  }

  .panel h3 {
    font-size: 2rem;
  }

  .panel p {
    font-size: 1rem;
  }

  .story-intro h2 {
    font-size: 2rem;
  }

  .panel,
  .story-intro {
    min-height: 90vh;
  }

  .footer {
    flex-direction: column;
    text-align: center;
  }
}

@media (max-width: 480px) {
  h1 {
    font-size: 1.75rem;
  }

  .panel h3 {
    font-size: 1.75rem;
  }

  .panel,
  .story-intro {
    min-height: 85vh;
    padding: 1.5rem;
  }

  .cta {
    flex-direction: column;
    width: 100%;
  }

  .btn {
    width: 100%;
  }
}