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

:root {
  --bg: #0f1117;
  --bg-card: #1a1d27;
  --bg-card-hover: #222632;
  --text: #e4e6ed;
  --text-muted: #9399a8;
  --accent: #6c8cff;
  --accent-hover: #8aa4ff;
  --accent-dim: rgba(108, 140, 255, 0.12);
  --border: #2a2e3a;
  --radius: 12px;
  --max-width: 1120px;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  color: var(--accent-hover);
  text-decoration: underline;
}

/* Layout */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.section-intro {
  text-align: center;
  color: var(--text-muted);
  max-width: 640px;
  margin: -16px auto 32px;
  font-size: 1.05rem;
}

/* Hero */
.hero {
  text-align: center;
  padding: 96px 24px 56px;
}

.hero h1 {
  font-size: 4rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  margin-bottom: 4px;
  background: linear-gradient(135deg, var(--accent) 0%, #a78bfa 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero .subtitle {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 16px;
}

.hero .tagline {
  font-size: 1.15rem;
  color: var(--text-muted);
  max-width: 620px;
  margin: 0 auto 36px;
}

.hero-actions {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

.hero .cta {
  display: inline-block;
  background: var(--accent);
  color: #fff;
  padding: 12px 32px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 1rem;
  transition:
    background 0.2s,
    transform 0.1s;
}

.hero .cta:hover {
  background: var(--accent-hover);
  text-decoration: none;
  transform: translateY(-1px);
}

.hero .cta-secondary {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text);
}

.hero .cta-secondary:hover {
  background: var(--bg-card);
  border-color: var(--accent);
}

/* Why SuiSui */
.why {
  padding: 48px 0;
}

.why h2 {
  text-align: center;
  font-size: 2rem;
  margin-bottom: 32px;
}

.highlights {
  display: flex;
  gap: 32px;
  justify-content: center;
  flex-wrap: wrap;
}

.highlight {
  display: flex;
  gap: 16px;
  max-width: 320px;
}

.highlight-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  min-width: 40px;
  border-radius: 50%;
  background: var(--accent-dim);
  color: var(--accent);
  font-weight: 700;
  font-size: 1.1rem;
}

.highlight strong {
  display: block;
  margin-bottom: 4px;
}

.highlight p {
  color: var(--text-muted);
  font-size: 0.92rem;
}

/* Features */
.features {
  padding: 48px 0;
}

.features h2 {
  text-align: center;
  font-size: 2rem;
  margin-bottom: 32px;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 16px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  transition:
    background 0.2s,
    border-color 0.2s;
}

.feature-card:hover {
  background: var(--bg-card-hover);
  border-color: var(--accent);
}

.feature-card h3 {
  font-size: 1.05rem;
  margin-bottom: 6px;
}

.feature-card p {
  color: var(--text-muted);
  font-size: 0.92rem;
}

/* Demos */
.demos {
  padding: 48px 0;
}

.demos h2 {
  text-align: center;
  font-size: 2rem;
  margin-bottom: 32px;
}

.demo-featured {
  margin-bottom: 24px;
}

.demo-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: border-color 0.2s;
}

.demo-card:hover {
  border-color: var(--accent);
}

.demo-card video {
  width: 100%;
  display: block;
}

.demo-card .demo-label {
  padding: 14px 20px;
  font-weight: 600;
  font-size: 0.95rem;
}

.demo-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

.demo-grid .demo-label {
  font-size: 0.85rem;
  padding: 10px 16px;
}

/* Center the last item when odd number of demos */
.demo-grid .demo-card:last-child:nth-child(odd) {
  grid-column: 1 / -1;
  max-width: calc(50% - 10px);
  justify-self: center;
}

/* Tech Stack */
.stack {
  padding: 48px 0;
}

.stack h2 {
  text-align: center;
  font-size: 2rem;
  margin-bottom: 32px;
}

.stack-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 16px;
  text-align: center;
}

.stack-item {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 16px;
}

.stack-item strong {
  display: block;
  font-size: 0.95rem;
  margin-bottom: 4px;
}

.stack-item span {
  color: var(--text-muted);
  font-size: 0.82rem;
}

/* Docs */
.docs {
  padding: 48px 0;
}

.docs h2 {
  text-align: center;
  font-size: 2rem;
  margin-bottom: 32px;
}

.docs-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
}

.doc-link {
  display: block;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  transition:
    background 0.2s,
    border-color 0.2s;
}

.doc-link:hover {
  background: var(--bg-card-hover);
  border-color: var(--accent);
  text-decoration: none;
}

.doc-link h3 {
  color: var(--text);
  font-size: 1rem;
  margin-bottom: 4px;
}

.doc-link p {
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* Footer */
footer {
  text-align: center;
  padding: 48px 24px;
  color: var(--text-muted);
  font-size: 0.9rem;
  border-top: 1px solid var(--border);
  margin-top: 48px;
}

footer p + p {
  margin-top: 8px;
}

/* Responsive */
@media (max-width: 640px) {
  .hero h1 {
    font-size: 2.8rem;
  }

  .hero .subtitle {
    font-size: 1.2rem;
  }

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

  .demo-grid {
    grid-template-columns: 1fr;
  }

  .stack-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}