:root {
  --bg: #07111f;
  --bg-2: #0c1d33;
  --surface: rgba(255, 255, 255, 0.04);
  --surface-2: rgba(255, 255, 255, 0.06);
  --border: rgba(255, 255, 255, 0.1);
  --text: #e8f0fb;
  --muted: #9fb2c9;
  --cyan: #38bdf8;
  --cyan-strong: #0ea5e9;
  --gold: #f5b14c;
  --radius: 18px;
  --maxw: 1080px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: radial-gradient(1200px 600px at 80% -10%, rgba(56, 189, 248, 0.12), transparent 60%),
    radial-gradient(900px 500px at 0% 0%, rgba(245, 177, 76, 0.08), transparent 55%),
    var(--bg);
  color: var(--text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }

.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 22px; }

/* ---------- Nav ---------- */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: rgba(7, 17, 31, 0.72);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.brand { display: flex; align-items: center; gap: 8px; font-weight: 700; }
.brand-mark { font-size: 22px; }
.brand-name { font-size: 19px; letter-spacing: 1px; }
.brand-badge {
  font-size: 11px; color: var(--gold); border: 1px solid rgba(245, 177, 76, 0.4);
  padding: 1px 7px; border-radius: 999px; margin-left: 4px;
}
.nav-links { display: flex; gap: 26px; font-size: 15px; color: var(--muted); }
.nav-links a:hover { color: var(--cyan); }

/* ---------- Hero ---------- */
.hero { padding: 96px 0 80px; text-align: center; }
.eyebrow {
  display: inline-block; font-size: 13px; letter-spacing: 1px; color: var(--cyan);
  border: 1px solid rgba(56, 189, 248, 0.3); padding: 5px 14px; border-radius: 999px; margin-bottom: 22px;
}
.hero-title { font-size: clamp(54px, 12vw, 110px); font-weight: 800; letter-spacing: 6px; line-height: 1.05;
  background: linear-gradient(180deg, #ffffff, #bfe6ff); -webkit-background-clip: text; background-clip: text; color: transparent; }
.hero-slogan { font-size: clamp(26px, 5vw, 40px); font-weight: 700; color: var(--cyan); margin-top: 14px; letter-spacing: 2px; }
.hero-sub-slogan { font-size: 17px; color: var(--gold); margin-top: 6px; letter-spacing: 1px; }
.hero-desc { max-width: 640px; margin: 22px auto 0; color: var(--muted); font-size: 16px; }
.hero-cta { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; margin-top: 34px; }

.btn {
  display: inline-block; padding: 13px 26px; border-radius: 999px; font-weight: 600; font-size: 15px;
  transition: transform .15s ease, box-shadow .15s ease, background .15s ease;
}
.btn-primary { background: linear-gradient(135deg, var(--cyan), var(--cyan-strong)); color: #04223a; box-shadow: 0 10px 30px rgba(56, 189, 248, .3); }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 14px 36px rgba(56, 189, 248, .42); }
.btn-ghost { border: 1px solid var(--border); color: var(--text); }
.btn-ghost:hover { border-color: var(--cyan); color: var(--cyan); }

/* ---------- Sections ---------- */
.section { padding: 78px 0; }
.section-alt { background: linear-gradient(180deg, rgba(255,255,255,0.02), rgba(255,255,255,0.04)); border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }
.section-title { font-size: clamp(26px, 4vw, 36px); font-weight: 700; text-align: center; }
.section-sub { text-align: center; color: var(--muted); margin-top: 12px; }

/* ---------- Tree ---------- */
.tree { max-width: 760px; margin: 44px auto 0; }
.tree-root {
  display: flex; flex-direction: column; align-items: center; gap: 4px;
  background: linear-gradient(135deg, rgba(56,189,248,.18), rgba(245,177,76,.12));
  border: 1px solid var(--border); border-radius: var(--radius);
  padding: 22px 40px; font-size: 26px; font-weight: 800; letter-spacing: 2px; margin: 0 auto; width: max-content;
}
.tree-root small { font-size: 12px; font-weight: 500; color: var(--muted); letter-spacing: 0; }
.tree-branches { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin-top: 22px; }
.tree-node {
  background: var(--surface); border: 1px solid var(--border); border-radius: 14px; padding: 16px;
  display: flex; flex-direction: column; align-items: center; gap: 6px; text-align: center;
}
.node-name { font-size: 18px; font-weight: 700; }
.node-tag { font-size: 12px; color: var(--muted); }

/* ---------- Cards ---------- */
.cards { display: grid; grid-template-columns: repeat(4, 1fr); gap: 22px; margin-top: 44px; }
.card {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 28px 24px;
  transition: transform .18s ease, border-color .18s ease;
}
.card:hover { transform: translateY(-4px); border-color: rgba(56,189,248,.5); }
.card-icon { font-size: 34px; }
.card h3 { font-size: 21px; margin-top: 12px; }
.card-tag { color: var(--cyan); font-size: 13px; margin: 6px 0 12px; }
.card-desc { color: var(--muted); font-size: 15px; min-height: 84px; }
.card-link { display: inline-block; margin-top: 14px; color: var(--gold); font-weight: 600; }
.card-link:hover { text-decoration: underline; }

/* ---------- Why ---------- */
.why-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; margin-top: 40px; }
.why-item { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 26px 22px; text-align: center; }
.why-icon { font-size: 32px; }
.why-item h3 { font-size: 18px; margin: 12px 0 8px; }
.why-item p { color: var(--muted); font-size: 14px; }

/* ---------- Trust ---------- */
.trust { display: flex; flex-wrap: wrap; gap: 18px 40px; justify-content: center; align-items: center; }
.trust span { color: var(--muted); font-size: 15px; }
.trust strong { color: var(--cyan); font-size: 26px; margin-right: 4px; }

/* ---------- CTA ---------- */
.cta { text-align: center; }
.cta-inner h2 { font-size: clamp(24px, 4vw, 34px); }
.cta-inner p { color: var(--muted); margin-top: 12px; }
.cta-inner .hero-cta { margin-top: 26px; }

/* ---------- Footer ---------- */
.footer { border-top: 1px solid var(--border); background: var(--bg-2); padding: 40px 0; }
.footer-inner { display: flex; flex-direction: column; align-items: center; gap: 16px; text-align: center; }
.footer-brand { display: flex; align-items: center; gap: 8px; font-weight: 700; }
.footer-tag { color: var(--muted); font-size: 12px; font-weight: 400; margin-left: 6px; }
.footer-links { display: flex; gap: 22px; flex-wrap: wrap; justify-content: center; color: var(--cyan); font-size: 14px; }
.footer-links a:hover { text-decoration: underline; }
.footer-copy { color: var(--muted); font-size: 13px; }

/* ---------- Relation note ---------- */
.relation-note { max-width: 760px; margin: 34px auto 0; text-align: center; color: var(--muted); font-size: 15px; line-height: 1.8; }
.relation-note strong { color: var(--text); }

/* ---------- Responsive ---------- */
@media (max-width: 860px) {
  .cards { grid-template-columns: repeat(2, 1fr); }
  .why-grid { grid-template-columns: 1fr; }
  .tree-branches { grid-template-columns: 1fr; }
  .nav-links { display: none; }
  .hero { padding: 70px 0 56px; }
}
@media (max-width: 560px) {
  .cards { grid-template-columns: 1fr; }
}