:root {
  --navy: #0b1024;
  --navy-2: #070b1a;
  --navy-card: #12172b;
  --cyan: #00c6fb;
  --cyan-2: #00bcd4;
  --teal: #177f73;
  --light: #f5f7fb;
  --card-light: #ffffff;
  --text-dark: #101935;
  --text-gray: #5b6675;
  --line: #e3e9f0;
  --green: #34d399;
  --amber: #fbbf24;
  --red: #f87171;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: "PingFang SC", "Microsoft YaHei", "Segoe UI", sans-serif;
  color: var(--text-dark);
  background: #fff;
  line-height: 1.7;
}
a { text-decoration: none; color: inherit; }
img { max-width: 100%; }

.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  background: rgba(11, 16, 36, 0.92); backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}
.nav-inner {
  max-width: 1180px; margin: 0 auto; padding: 14px 22px;
  display: flex; align-items: center; gap: 28px;
}
.brand { display: flex; align-items: center; gap: 10px; color: #fff; font-weight: 700; font-size: 18px; }
.brand img { width: 34px; height: 34px; }
.nav-links { display: flex; gap: 22px; margin-left: 12px; }
.nav-links a { color: #c7d0e4; font-size: 14px; }
.nav-links a:hover, .nav-links a.active { color: var(--cyan); }
.nav-cta { margin-left: auto; display: flex; gap: 10px; align-items: center; }
.btn {
  display: inline-block; border-radius: 8px; padding: 9px 20px;
  font-size: 14px; font-weight: 600; border: none; cursor: pointer; transition: all .2s;
}
.btn-primary {
  background: linear-gradient(90deg, var(--cyan-2), var(--cyan));
  color: #06121f;
}
.btn-primary:hover { transform: translateY(-1px); box-shadow: 0 6px 18px rgba(0, 198, 251, .35); }
.btn-ghost { background: rgba(255, 255, 255, .08); color: #fff; border: 1px solid rgba(255,255,255,.2); }
.btn-ghost:hover { background: rgba(255, 255, 255, .16); }
.btn-dark { background: var(--navy); color: #fff; }
.btn-dark:hover { background: #182046; }
.btn-lg { padding: 13px 30px; font-size: 16px; border-radius: 10px; }

.hero {
  background:
    radial-gradient(900px 500px at 85% -10%, rgba(0,198,251,.22), transparent 60%),
    radial-gradient(700px 420px at 10% 110%, rgba(23,127,115,.25), transparent 60%),
    var(--navy);
  color: #fff; padding: 150px 22px 96px; text-align: center;
}
.hero h1 { font-size: 46px; line-height: 1.3; font-weight: 800; }
.hero h1 .grad {
  background: linear-gradient(90deg, var(--cyan-2), var(--cyan));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero p { max-width: 720px; margin: 22px auto 34px; color: #b9c4da; font-size: 17px; }
.hero-actions { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }
.hero-stats {
  display: flex; justify-content: center; gap: 12px; flex-wrap: wrap; margin-top: 56px;
}
.stat {
  background: rgba(255,255,255,.05); border: 1px solid rgba(255,255,255,.1);
  border-radius: 14px; padding: 18px 30px; min-width: 150px;
}
.stat b { display: block; font-size: 26px; color: var(--cyan); }
.stat span { font-size: 13px; color: #9aa8c2; }

.section { padding: 84px 22px; }
.section.light { background: var(--light); }
.section-head { text-align: center; max-width: 720px; margin: 0 auto 52px; }
.section-head h2 { font-size: 32px; font-weight: 800; }
.section-head p { color: var(--text-gray); margin-top: 12px; }
.container { max-width: 1180px; margin: 0 auto; }

.pillars { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.pillar {
  background: var(--card-light); border: 1px solid var(--line); border-radius: 16px;
  padding: 30px 26px; transition: all .25s;
}
.pillar:hover { transform: translateY(-4px); box-shadow: 0 14px 34px rgba(16,25,53,.08); }
.pillar .ico {
  width: 48px; height: 48px; border-radius: 12px; display: grid; place-items: center;
  font-size: 22px; color: #fff; margin-bottom: 18px;
}
.pillar h3 { font-size: 18px; margin-bottom: 8px; }
.pillar p { color: var(--text-gray); font-size: 14px; }

.features { display: grid; grid-template-columns: repeat(4, 1fr); gap: 22px; }
.feature {
  background: var(--navy-card); border: 1px solid rgba(255,255,255,.08);
  border-radius: 16px; padding: 28px 24px; color: #fff;
}
.feature .ico { font-size: 26px; margin-bottom: 14px; }
.feature h3 { font-size: 17px; margin-bottom: 8px; }
.feature p { color: #9aa8c2; font-size: 13.5px; }

.nodes-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.node-chip {
  background: var(--card-light); border: 1px solid var(--line); border-radius: 12px;
  padding: 18px 20px; display: flex; align-items: center; gap: 12px;
}
.node-chip .dot { width: 10px; height: 10px; border-radius: 50%; background: var(--green); box-shadow: 0 0 0 4px rgba(52,211,153,.18); }
.node-chip b { font-size: 15px; }
.node-chip span { font-size: 12px; color: var(--text-gray); display: block; }

.pricing-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; align-items: stretch; }
.plan {
  background: var(--card-light); border: 1px solid var(--line); border-radius: 18px;
  padding: 34px 30px; display: flex; flex-direction: column; position: relative;
}
.plan.hot { border: 2px solid var(--cyan); box-shadow: 0 16px 40px rgba(0,198,251,.14); }
.plan .badge {
  position: absolute; top: -13px; left: 50%; transform: translateX(-50%);
  background: linear-gradient(90deg, var(--cyan-2), var(--cyan)); color: #06121f;
  font-size: 12px; font-weight: 700; padding: 4px 14px; border-radius: 20px;
}
.plan h3 { font-size: 18px; }
.plan .price { margin: 14px 0 4px; font-size: 34px; font-weight: 800; color: var(--navy); }
.plan .price small { font-size: 14px; color: var(--text-gray); font-weight: 400; }
.plan ul { list-style: none; margin: 18px 0 26px; flex: 1; }
.plan ul li { padding: 7px 0 7px 26px; position: relative; font-size: 14px; color: #3d485c; }
.plan ul li::before { content: "✓"; position: absolute; left: 0; color: var(--teal); font-weight: 700; }
.plan .btn { text-align: center; }

.howto { display: grid; grid-template-columns: repeat(4, 1fr); gap: 22px; }
.step {
  background: var(--card-light); border: 1px solid var(--line); border-radius: 16px; padding: 26px;
}
.step .num {
  width: 40px; height: 40px; border-radius: 50%; display: grid; place-items: center;
  background: linear-gradient(135deg, var(--cyan-2), var(--cyan)); color: #06121f; font-weight: 800; margin-bottom: 14px;
}
.step h3 { font-size: 16px; margin-bottom: 6px; }
.step p { color: var(--text-gray); font-size: 13.5px; }

.faq { max-width: 820px; margin: 0 auto; }
.faq-item {
  background: var(--card-light); border: 1px solid var(--line); border-radius: 12px;
  padding: 20px 24px; margin-bottom: 12px;
}
.faq-item h3 { font-size: 15.5px; margin-bottom: 6px; color: var(--navy); }
.faq-item p { color: var(--text-gray); font-size: 14px; }

.cta {
  background:
    radial-gradient(700px 400px at 80% 0%, rgba(0,198,251,.25), transparent 60%),
    var(--navy-2);
  color: #fff; text-align: center; padding: 90px 22px;
}
.cta h2 { font-size: 32px; margin-bottom: 14px; }
.cta p { color: #9aa8c2; margin-bottom: 30px; }

.footer { background: var(--navy-2); color: #8c97af; padding: 44px 22px 30px; font-size: 13px; }
.footer-inner { max-width: 1180px; margin: 0 auto; display: flex; gap: 40px; flex-wrap: wrap; }
.footer .col { flex: 1; min-width: 180px; }
.footer h4 { color: #fff; font-size: 14px; margin-bottom: 14px; }
.footer a { display: block; color: #8c97af; padding: 4px 0; }
.footer a:hover { color: var(--cyan); }
.footer .bottom { max-width: 1180px; margin: 30px auto 0; border-top: 1px solid rgba(255,255,255,.08); padding-top: 18px; text-align: center; }

.auth-wrap { min-height: 100vh; display: grid; place-items: center; background: var(--navy); padding: 90px 20px; }
.auth-card {
  background: #fff; border-radius: 18px; width: 100%; max-width: 420px; padding: 36px 34px;
  box-shadow: 0 24px 60px rgba(0,0,0,.35);
}
.auth-card h1 { font-size: 22px; text-align: center; }
.auth-card .sub { text-align: center; color: var(--text-gray); font-size: 13px; margin: 8px 0 24px; }
.field { margin-bottom: 16px; }
.field label { display: block; font-size: 13px; color: #3d485c; margin-bottom: 6px; }
.field input {
  width: 100%; padding: 11px 14px; border: 1px solid var(--line); border-radius: 8px;
  font-size: 14px; outline: none;
}
.field input:focus { border-color: var(--cyan); box-shadow: 0 0 0 3px rgba(0,198,251,.15); }
.auth-card .btn { width: 100%; text-align: center; margin-top: 6px; }
.auth-card .switch { text-align: center; font-size: 13px; margin-top: 18px; color: var(--text-gray); }
.auth-card .switch a { color: var(--cyan-2); font-weight: 600; }
.notice {
  margin-top: 18px; background: #f0f9ff; border: 1px solid #bae6fd; color: #0369a1;
  border-radius: 8px; padding: 10px 12px; font-size: 12.5px;
}

.download-card {
  background: var(--card-light); border: 1px solid var(--line); border-radius: 18px;
  padding: 40px; display: flex; gap: 36px; align-items: center; flex-wrap: wrap;
}
.download-card .info { flex: 1; min-width: 300px; }
.download-card h2 { font-size: 24px; }
.download-card p { color: var(--text-gray); margin: 12px 0 22px; }
.steps-note { margin-top: 40px; }
.steps-note ol { margin-left: 20px; color: var(--text-gray); }

@media (max-width: 900px) {
  .nav-links { display: none; }
  .pillars, .features, .pricing-grid, .howto, .nodes-grid { grid-template-columns: 1fr 1fr; }
  .hero h1 { font-size: 34px; }
}
@media (max-width: 620px) {
  .pillars, .features, .pricing-grid, .howto, .nodes-grid { grid-template-columns: 1fr; }
  .hero h1 { font-size: 28px; }
}

/* ===== 手机版底部导航 ===== */
.mobile-nav {
  position: fixed; left: 0; right: 0; bottom: 0; z-index: 1000;
  display: none;
  background: rgba(16,25,53,.97);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  border-top: 1px solid rgba(255,255,255,.08);
  padding: 6px 4px calc(6px + env(safe-area-inset-bottom));
}
.mobile-nav a, .mobile-nav .mn-btn {
  flex: 1; display: flex; flex-direction: column; align-items: center; gap: 3px;
  color: #8c97af; font-size: 11px; text-decoration: none;
  background: none; border: none; cursor: pointer; padding: 5px 0; font-family: inherit;
}
.mobile-nav a:active, .mobile-nav .mn-btn:active { color: var(--cyan); }
.mobile-nav .mn-ico { font-size: 20px; line-height: 1; }
.mobile-menu {
  position: fixed; left: 0; right: 0; bottom: 60px; z-index: 999;
  background: rgba(16,25,53,.98);
  border-top: 1px solid rgba(255,255,255,.08);
  border-radius: 14px 14px 0 0;
  padding: 8px 18px calc(8px + env(safe-area-inset-bottom));
  display: none;
}
.mobile-menu.show { display: block; }
.mobile-menu a {
  display: block; color: #dfe6f3; padding: 13px 4px; font-size: 14px;
  text-decoration: none; border-bottom: 1px solid rgba(255,255,255,.05);
}
.mobile-menu a:last-child { border-bottom: none; }
@media (max-width: 900px) {
  .mobile-nav { display: flex; }
  body:has(.mobile-nav) { padding-bottom: 62px; }
}