:root {
  --bg: #070a12;
  --bg-elevated: #0d1422;
  --text: #e8eefc;
  --muted: #9aa8c7;
  --line: rgba(148, 163, 184, 0.18);
  --accent: #5eead4;
  --accent-2: #60a5fa;
  --radius: 18px;
  --max: 1120px;
  --nav-h: 72px;
  font-family: "SF Pro Display", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  overflow-x: hidden;
}
a { color: inherit; text-decoration: none; }
img, svg { max-width: 100%; display: block; }

.bg-grid {
  position: fixed; inset: 0; pointer-events: none; z-index: 0;
  background-image:
    linear-gradient(rgba(94,234,212,0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(96,165,250,0.04) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: radial-gradient(ellipse at center, black 20%, transparent 75%);
}
.bg-glow {
  position: fixed; inset: auto auto 10% -10%; width: 55vw; height: 55vw; pointer-events: none; z-index: 0;
  background: radial-gradient(circle, rgba(96,165,250,0.18), transparent 60%);
  filter: blur(20px);
}

.nav {
  position: sticky; top: 0; z-index: 20;
  backdrop-filter: blur(16px);
  background: rgba(7,10,18,0.72);
  border-bottom: 1px solid var(--line);
}
.nav-inner {
  max-width: var(--max); margin: 0 auto; min-height: var(--nav-h);
  padding: 0 20px; display: flex; align-items: center; justify-content: space-between; gap: 16px;
}
.brand { display: flex; align-items: center; gap: 12px; }
.brand-mark {
  width: 34px; height: 34px; border-radius: 10px;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  box-shadow: 0 0 24px rgba(94,234,212,0.35);
}
.brand-text { display: flex; flex-direction: column; line-height: 1.15; }
.brand-text strong { font-size: 15px; letter-spacing: 0.02em; }
.brand-text small { color: var(--muted); font-size: 11px; letter-spacing: 0.08em; text-transform: uppercase; }
.nav-links { display: flex; gap: 22px; align-items: center; }
.nav-links a { color: var(--muted); font-size: 14px; }
.nav-links a:hover { color: var(--text); }
.nav-toggle {
  display: none; width: 42px; height: 42px; border: 1px solid var(--line);
  border-radius: 12px; background: transparent; cursor: pointer; padding: 10px;
}
.nav-toggle span {
  display: block; height: 2px; margin: 6px 0; background: var(--text); border-radius: 2px;
}

.hero {
  position: relative; z-index: 1;
  max-width: var(--max); margin: 0 auto;
  padding: 72px 20px 48px;
  display: grid; grid-template-columns: 1.2fr 0.8fr; gap: 40px; align-items: center;
}
.eyebrow {
  display: inline-block; margin: 0 0 14px;
  color: var(--accent); letter-spacing: 0.18em; font-size: 12px;
}
.hero h1 {
  margin: 0; font-size: clamp(40px, 7vw, 64px); line-height: 1.05; letter-spacing: 0.02em;
}
.hero-en {
  margin: 10px 0 0; color: var(--muted); letter-spacing: 0.28em; font-size: 13px;
}
.hero-lead {
  margin: 28px 0 0; font-size: clamp(24px, 4vw, 36px); line-height: 1.25; font-weight: 600;
  background: linear-gradient(90deg, #fff, #9cdcff 50%, #5eead4);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero-desc { margin: 22px 0 0; max-width: 560px; color: var(--muted); font-size: 16px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 32px; }
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  min-height: 46px; padding: 0 20px; border-radius: 999px; font-size: 14px; border: 1px solid transparent;
}
.btn-primary {
  background: linear-gradient(135deg, #2dd4bf, #3b82f6); color: #041018; font-weight: 600;
  box-shadow: 0 10px 30px rgba(59,130,246,0.25);
}
.btn-ghost {
  border-color: var(--line); color: var(--text); background: rgba(255,255,255,0.02);
}
.btn-ghost:hover { border-color: rgba(94,234,212,0.45); }
.hero-visual { display: flex; justify-content: center; }
.node-graph { width: min(100%, 380px); opacity: 0.95; }

.section { position: relative; z-index: 1; max-width: var(--max); margin: 0 auto; padding: 72px 20px; }
.section.alt { 
  max-width: none; padding-left: 0; padding-right: 0;
  background: linear-gradient(180deg, rgba(13,20,34,0.2), rgba(13,20,34,0.65));
  border-top: 1px solid var(--line); border-bottom: 1px solid var(--line);
}
.section.alt .section-head, .section.alt .card-grid {
  max-width: var(--max); margin-left: auto; margin-right: auto; padding-left: 20px; padding-right: 20px;
}
.section-head { margin-bottom: 28px; }
.section-head h2 { margin: 0; font-size: clamp(28px, 4vw, 36px); }
.section-head p { margin: 10px 0 0; color: var(--muted); }

.card-grid {
  display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px;
}
.card {
  padding: 24px; border-radius: var(--radius);
  background: rgba(255,255,255,0.025);
  border: 1px solid var(--line);
  box-shadow: inset 0 1px 0 rgba(255,255,255,0.03);
}
.card h3 { margin: 0 0 10px; font-size: 18px; }
.card p { margin: 0; color: var(--muted); font-size: 15px; }

.about {
  max-width: 760px;
  padding: 28px; border-radius: 24px;
  border: 1px solid var(--line);
  background: linear-gradient(160deg, rgba(94,234,212,0.06), rgba(96,165,250,0.03));
}
.about h2 { margin: 0 0 16px; font-size: clamp(28px, 4vw, 36px); }
.about p { color: var(--muted); margin: 0 0 14px; }
.about p:last-child { margin-bottom: 0; }

.footer {
  position: relative; z-index: 1;
  border-top: 1px solid var(--line);
  padding: 48px 20px 56px; text-align: center;
}
.footer-en { margin: 0; letter-spacing: 0.22em; color: var(--accent); font-size: 12px; }
.footer-zh { margin: 8px 0 0; font-size: 18px; font-weight: 600; }
.footer-tag { margin: 10px 0 0; color: var(--muted); }
.footer-copy { margin: 18px 0 0; color: #7b879e; font-size: 13px; }
.footer-beian { margin: 12px 0 0; display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }
.beian { color: #7b879e; font-size: 13px; }
.beian:hover { color: var(--accent); }

@media (max-width: 860px) {
  .hero { grid-template-columns: 1fr; padding-top: 48px; }
  .hero-visual { order: -1; }
  .node-graph { width: min(100%, 280px); }
  .card-grid { grid-template-columns: 1fr; }
  .nav-toggle { display: inline-block; }
  .nav-links {
    display: none; position: absolute; left: 12px; right: 12px; top: calc(var(--nav-h) + 8px);
    flex-direction: column; align-items: stretch; gap: 0;
    padding: 8px; border-radius: 16px; border: 1px solid var(--line);
    background: rgba(10,14,24,0.96);
  }
  .nav-links a { padding: 12px 14px; border-radius: 10px; }
  .nav-links.open { display: flex; }
}