:root {
  --bg: #070b12;
  --bg-elevated: #0d1420;
  --bg-card: #111827;
  --border: rgba(148, 163, 184, 0.12);
  --text: #e2e8f0;
  --text-muted: #94a3b8;
  --accent: #22d3ee;
  --accent-dim: rgba(34, 211, 238, 0.15);
  --accent-glow: rgba(34, 211, 238, 0.35);
  --green: #34d399;
  --font-sans: "Instrument Sans", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-mono: "JetBrains Mono", "SF Mono", "Menlo", monospace;
  --radius: 12px;
  --max-w: 1120px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

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

a:hover {
  text-decoration: underline;
}

.container {
  width: min(100% - 2rem, var(--max-w));
  margin-inline: auto;
}

/* ── Nav ── */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px);
  background: rgba(7, 11, 18, 0.85);
  border-bottom: 1px solid var(--border);
}

.site-nav .inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--text);
  text-decoration: none;
}

.logo:hover {
  text-decoration: none;
}

.logo-img {
  width: 32px;
  height: 32px;
  display: block;
  flex-shrink: 0;
  border-radius: 8px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.75rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-links a {
  color: var(--text-muted);
  font-size: 0.925rem;
  font-weight: 500;
  text-decoration: none;
  transition: color 0.15s;
}

.nav-links a:hover {
  color: var(--text);
  text-decoration: none;
}

.nav-cta {
  padding: 0.45rem 1rem;
  border-radius: 8px;
  background: var(--accent-dim);
  border: 1px solid rgba(34, 211, 238, 0.35);
  color: var(--accent) !important;
}

.nav-cta:hover {
  background: rgba(34, 211, 238, 0.25);
}

.menu-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text);
  font-size: 1.5rem;
  cursor: pointer;
  padding: 0.25rem;
}

/* ── Hero ── */
.hero {
  position: relative;
  padding: 5rem 0 4.5rem;
  overflow: hidden;
}

.hero-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(34, 211, 238, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(34, 211, 238, 0.04) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: radial-gradient(ellipse 80% 70% at 50% 0%, black, transparent);
}

.hero-glow {
  position: absolute;
  top: -120px;
  left: 50%;
  transform: translateX(-50%);
  width: 640px;
  height: 400px;
  background: radial-gradient(ellipse, var(--accent-glow), transparent 70%);
  pointer-events: none;
  opacity: 0.5;
}

.hero-content {
  position: relative;
  text-align: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.35rem 0.85rem;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--bg-elevated);
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
}

.hero-badge span {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--green);
  box-shadow: 0 0 8px var(--green);
}

.hero h1 {
  font-size: clamp(2.5rem, 6vw, 3.75rem);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.03em;
  margin: 0 0 1.25rem;
}

.hero h1 em {
  font-style: normal;
  background: linear-gradient(90deg, var(--accent), #a78bfa);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero-lead {
  font-size: 1.15rem;
  color: var(--text-muted);
  max-width: 640px;
  margin: 0 auto 2rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  justify-content: center;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.7rem 1.35rem;
  border-radius: 10px;
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  transition: transform 0.15s, box-shadow 0.15s;
  cursor: pointer;
  border: none;
  font-family: inherit;
}

.btn:hover {
  text-decoration: none;
  transform: translateY(-1px);
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent), #0891b2);
  color: var(--bg);
  box-shadow: 0 4px 24px var(--accent-glow);
}

.btn-secondary {
  background: var(--bg-card);
  color: var(--text);
  border: 1px solid var(--border);
}

.btn-secondary:hover {
  border-color: rgba(34, 211, 238, 0.4);
}

.btn-ghost {
  background: transparent;
  color: var(--text-muted);
  border: 1px solid transparent;
}

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

/* ── Download ── */
#download {
  padding-top: 2rem;
}

.download-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.download-card {
  padding: 1.15rem 1.25rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--bg-card);
}

.download-card--highlight {
  border-color: rgba(34, 211, 238, 0.35);
  background: linear-gradient(145deg, var(--bg-card), rgba(34, 211, 238, 0.06));
}

.download-card h3 {
  margin: 0 0 0.25rem;
  font-size: 0.95rem;
}

.download-arch {
  margin: 0 0 0.65rem;
  font-size: 0.75rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

.download-card code {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--accent);
  word-break: break-all;
  line-height: 1.45;
}

.download-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  justify-content: center;
  margin-bottom: 1.5rem;
}

.download-install {
  max-width: 720px;
  margin-inline: auto;
}

/* ── Sections ── */
section {
  padding: 4.5rem 0;
}

.section-label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--accent);
  margin-bottom: 0.75rem;
}

.section-title {
  font-size: clamp(1.75rem, 4vw, 2.25rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 0 0 0.75rem;
}

.section-desc {
  color: var(--text-muted);
  max-width: 560px;
  margin: 0 0 2.5rem;
}

.section-header.center {
  text-align: center;
}

.section-header.center .section-desc {
  margin-inline: auto;
}

/* ── Feature section ── */
.features-section {
  position: relative;
  overflow: hidden;
}

.features-bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 60% 50% at 20% 30%, rgba(34, 211, 238, 0.06), transparent),
    radial-gradient(ellipse 50% 40% at 80% 70%, rgba(167, 139, 250, 0.06), transparent);
  pointer-events: none;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  position: relative;
}

.feature-card {
  position: relative;
  padding: 1.5rem 1.5rem 1.35rem;
  border-radius: 16px;
  background: rgba(17, 24, 39, 0.65);
  border: 1px solid var(--border);
  backdrop-filter: blur(8px);
  transition: transform 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease;
  overflow: hidden;
}

.feature-card--wide {
  grid-column: span 2;
}

.feature-card--full {
  grid-column: 1 / -1;
}

.feature-card__glow {
  position: absolute;
  top: -40%;
  right: -20%;
  width: 180px;
  height: 180px;
  border-radius: 50%;
  opacity: 0;
  filter: blur(48px);
  transition: opacity 0.35s ease;
  pointer-events: none;
}

.feature-card:hover {
  transform: translateY(-4px);
  border-color: rgba(255, 255, 255, 0.12);
  box-shadow: 0 16px 48px rgba(0, 0, 0, 0.35);
}

.feature-card:hover .feature-card__glow {
  opacity: 1;
}

.feature-card[data-accent="cyan"] { --card-accent: #22d3ee; --card-accent-dim: rgba(34, 211, 238, 0.12); }
.feature-card[data-accent="violet"] { --card-accent: #a78bfa; --card-accent-dim: rgba(167, 139, 250, 0.12); }
.feature-card[data-accent="emerald"] { --card-accent: #34d399; --card-accent-dim: rgba(52, 211, 153, 0.12); }
.feature-card[data-accent="amber"] { --card-accent: #fbbf24; --card-accent-dim: rgba(251, 191, 36, 0.12); }
.feature-card[data-accent="rose"] { --card-accent: #fb7185; --card-accent-dim: rgba(251, 113, 133, 0.12); }
.feature-card[data-accent="sky"] { --card-accent: #38bdf8; --card-accent-dim: rgba(56, 189, 248, 0.12); }

.feature-card[data-accent] .feature-card__glow {
  background: var(--card-accent);
}

.feature-card[data-accent]::before {
  content: "";
  position: absolute;
  top: 0;
  left: 1.5rem;
  right: 1.5rem;
  height: 2px;
  border-radius: 0 0 2px 2px;
  background: linear-gradient(90deg, transparent, var(--card-accent), transparent);
  opacity: 0;
  transition: opacity 0.25s ease;
}

.feature-card[data-accent]:hover::before {
  opacity: 1;
}

.feature-card__head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  margin-bottom: 1.1rem;
}

.feature-icon {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  display: grid;
  place-items: center;
  background: var(--card-accent-dim, var(--accent-dim));
  border: 1px solid rgba(255, 255, 255, 0.06);
  color: var(--card-accent, var(--accent));
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.feature-icon svg {
  width: 22px;
  height: 22px;
}

.feature-card:hover .feature-icon {
  transform: scale(1.06);
  box-shadow: 0 0 20px var(--card-accent-dim, var(--accent-dim));
}

.feature-num {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  opacity: 0.45;
}

.feature-card h3 {
  margin: 0 0 0.5rem;
  font-size: 1.1rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.feature-card p {
  margin: 0 0 1rem;
  font-size: 0.9rem;
  line-height: 1.65;
  color: var(--text-muted);
}

.feature-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.feature-tags li {
  padding: 0.2rem 0.55rem;
  border-radius: 6px;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  font-weight: 500;
  color: var(--card-accent, var(--accent));
  background: var(--card-accent-dim, var(--accent-dim));
  border: 1px solid rgba(255, 255, 255, 0.05);
}

@media (max-width: 960px) {
  .feature-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .feature-card--wide {
    grid-column: span 2;
  }
}

@media (max-width: 560px) {
  .feature-grid {
    grid-template-columns: 1fr;
  }

  .feature-card--wide,
  .feature-card--full {
    grid-column: span 1;
  }
}

/* ── Entry pills ── */
.entry-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.entry-pill {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.65rem 1.1rem;
  border-radius: 999px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text);
}

.entry-pill code {
  color: var(--accent);
}

/* ── Architecture ── */
.arch-flow {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 0.75rem;
  align-items: stretch;
}

.arch-node {
  padding: 1rem;
  text-align: center;
  border-radius: var(--radius);
  background: var(--bg-card);
  border: 1px solid var(--border);
  font-size: 0.875rem;
}

.arch-node strong {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--accent);
  margin-bottom: 0.35rem;
}

.arch-arrow {
  display: none;
}

/* ── Code block ── */
.code-block {
  position: relative;
  border-radius: var(--radius);
  background: #0a0f18;
  border: 1px solid var(--border);
  overflow: hidden;
}

.code-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.65rem 1rem;
  background: var(--bg-elevated);
  border-bottom: 1px solid var(--border);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-muted);
}

.copy-btn {
  padding: 0.25rem 0.65rem;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  cursor: pointer;
  transition: color 0.15s, border-color 0.15s;
}

.copy-btn:hover {
  color: var(--accent);
  border-color: rgba(34, 211, 238, 0.4);
}

.code-block pre {
  margin: 0;
  padding: 1.25rem;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  line-height: 1.65;
  color: #cbd5e1;
}

.code-block .comment { color: #64748b; }
.code-block .cmd { color: var(--accent); }
.code-block .flag { color: #a78bfa; }
.code-block .str { color: #34d399; }

/* ── Channel cards ── */
.channel-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
}

.channel-card {
  padding: 1.25rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--bg-card);
}

.channel-card h3 {
  margin: 0 0 0.35rem;
  font-size: 1rem;
}

.channel-card p {
  margin: 0;
  font-size: 0.875rem;
  color: var(--text-muted);
}

.channel-tag {
  display: inline-block;
  margin-top: 0.65rem;
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.tag-cn { background: rgba(52, 211, 153, 0.15); color: var(--green); }
.tag-global { background: rgba(148, 163, 184, 0.15); color: var(--text-muted); }

.channel-doc {
  display: inline-block;
  margin-top: 0.75rem;
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--accent);
  text-decoration: none;
}

.channel-doc:hover {
  text-decoration: underline;
}

/* ── Hero stats ── */
.hero-stats {
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
  margin: 2rem 0 0;
  padding: 0;
  list-style: none;
}

.hero-stats li {
  font-size: 0.875rem;
  color: var(--text-muted);
}

.hero-stats strong {
  display: block;
  font-family: var(--font-mono);
  font-size: 1.25rem;
  color: var(--accent);
  font-weight: 600;
}

/* ── Platform cards ── */
.platform-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1rem;
}

.platform-card {
  padding: 1.25rem 1.5rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--bg-card);
}

.platform-card h3 {
  margin: 0 0 0.75rem;
  font-size: 1rem;
}

.platform-card ul {
  margin: 0 0 1rem;
  padding-left: 1.1rem;
  font-size: 0.875rem;
  color: var(--text-muted);
}

.platform-card li {
  margin-bottom: 0.35rem;
}

.platform-card code {
  font-family: var(--font-mono);
  font-size: 0.8em;
  color: var(--accent);
}

.platform-card > a {
  font-size: 0.85rem;
  font-weight: 500;
}

/* ── Docs links ── */
.docs-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1rem;
}

.doc-link {
  display: block;
  padding: 1.25rem 1.5rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--text);
  text-decoration: none;
  transition: border-color 0.2s;
}

.doc-link:hover {
  border-color: rgba(34, 211, 238, 0.4);
  text-decoration: none;
}

.doc-link h3 {
  margin: 0 0 0.35rem;
  font-size: 1rem;
}

.doc-link p {
  margin: 0;
  font-size: 0.875rem;
  color: var(--text-muted);
}

.doc-link .arrow {
  float: right;
  color: var(--accent);
}

/* ── Footer ── */
.site-footer {
  padding: 2.5rem 0;
  border-top: 1px solid var(--border);
  text-align: center;
  color: var(--text-muted);
  font-size: 0.875rem;
}

.site-footer a {
  color: var(--text-muted);
}

.site-footer a:hover {
  color: var(--accent);
}

.site-footer .footer-icp {
  margin-top: 0.75rem;
  font-size: 0.8125rem;
}

/* ── Responsive ── */
@media (max-width: 768px) {
  .menu-toggle {
    display: block;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    padding: 1rem;
    background: var(--bg-elevated);
    border-bottom: 1px solid var(--border);
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links li {
    width: 100%;
  }

  .nav-links a {
    display: block;
    padding: 0.75rem 0;
  }

  .hero {
    padding: 3.5rem 0 3rem;
  }
}

@media (min-width: 900px) {
  .arch-flow {
    grid-template-columns: 1fr auto 1fr auto 1fr auto 1fr;
  }

  .arch-arrow {
    display: flex;
    align-items: center;
    color: var(--text-muted);
    font-size: 1.25rem;
  }
}