:root {
  --bg: #0f1419;
  --surface: #1a2332;
  --surface2: #243044;
  --border: #2d3a4f;
  --text: #e8edf4;
  --muted: #8b9cb3;
  --accent: #3b82f6;
  --accent2: #60a5fa;
  --green: #22c55e;
  --amber: #f59e0b;
  --red: #ef4444;
  --radius: 12px;
  --max: 1100px;
}

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

body {
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

a { color: var(--accent2); text-decoration: none; }
a:hover { text-decoration: underline; }

.nav {
  position: sticky; top: 0; z-index: 100;
  background: rgba(15,20,25,.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  max-width: var(--max); margin: 0 auto;
  padding: 14px 24px;
  display: flex; align-items: center; gap: 24px;
}
.logo { font-weight: 800; font-size: 1.1rem; color: var(--text); }
.logo span { color: var(--accent2); }
.nav-links { display: flex; gap: 20px; margin-left: auto; font-size: 0.9rem; }
.nav-links a { color: var(--muted); }
.nav-links a.active, .nav-links a:hover { color: var(--text); text-decoration: none; }
.nav-back {
  font-size: 0.82rem; font-weight: 600; color: var(--muted);
  padding: 6px 12px; border: 1px solid var(--border); border-radius: 6px;
  text-decoration: none !important; white-space: nowrap;
  transition: color .15s, border-color .15s;
}
.nav-back:hover { color: var(--accent2); border-color: var(--accent); }

.container { max-width: var(--max); margin: 0 auto; padding: 40px 24px 80px; }

.hero { text-align: center; padding: 48px 0 56px; }
.hero-tag {
  display: inline-block; font-size: 12px; letter-spacing: .08em;
  text-transform: uppercase; color: var(--accent2);
  background: rgba(59,130,246,.12); padding: 6px 14px; border-radius: 20px;
  margin-bottom: 16px;
}
.hero h1 { font-size: 2.4rem; font-weight: 800; line-height: 1.25; margin-bottom: 16px; }
.hero p { color: var(--muted); max-width: 640px; margin: 0 auto 28px; font-size: 1.05rem; }
.hero-btns { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }

.btn {
  display: inline-block; padding: 12px 24px; border-radius: 8px;
  font-weight: 600; font-size: 0.95rem; border: none; cursor: pointer;
  transition: transform .15s, box-shadow .15s;
}
.btn:hover { transform: translateY(-1px); text-decoration: none; }
.btn-primary { background: var(--accent); color: #fff; }
.btn-secondary { background: var(--surface2); color: var(--text); border: 1px solid var(--border); }
.btn-ghost { background: transparent; color: var(--accent2); border: 1px solid var(--accent); }

.section-title { font-size: 1.5rem; font-weight: 700; margin-bottom: 8px; }
.section-desc { color: var(--muted); margin-bottom: 28px; }

.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 28px; position: relative;
  transition: border-color .2s, transform .2s;
}
.card:hover { border-color: var(--accent); transform: translateY(-2px); }
.card-tier { font-size: 11px; font-weight: 700; letter-spacing: .06em; color: var(--accent2); }
.card h3 { font-size: 1.25rem; margin: 8px 0; }
.card .price { font-size: 1.5rem; font-weight: 800; color: var(--green); margin: 12px 0; }
.card .price small { font-size: 0.85rem; color: var(--muted); font-weight: 400; }
.card ul { list-style: none; font-size: 0.88rem; color: var(--muted); }
.card ul li { padding: 6px 0; border-bottom: 1px solid var(--border); }
.card ul li:last-child { border: none; }
.card .card-cta { margin-top: 20px; }

.compare-table {
  width: 100%; border-collapse: collapse; font-size: 0.9rem;
  background: var(--surface); border-radius: var(--radius); overflow: hidden;
}
.compare-table th, .compare-table td {
  padding: 14px 16px; border-bottom: 1px solid var(--border); text-align: left;
}
.compare-table th { background: var(--surface2); color: var(--muted); font-weight: 600; }
.compare-table tr:last-child td { border: none; }
.yes { color: var(--green); }
.no { color: var(--muted); }

.callout {
  background: rgba(59,130,246,.08); border: 1px solid rgba(59,130,246,.25);
  border-radius: var(--radius); padding: 20px 24px; margin: 32px 0;
}
.callout strong { color: var(--accent2); }

.footer {
  border-top: 1px solid var(--border); padding: 32px 24px;
  text-align: center; color: var(--muted); font-size: 0.85rem;
}

/* L2 demo */
.demo-layout { display: grid; grid-template-columns: 1fr 340px; gap: 24px; align-items: start; }
.demo-panel {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); overflow: hidden;
}
.demo-header {
  padding: 16px 20px; background: var(--surface2);
  border-bottom: 1px solid var(--border); font-weight: 600;
}
.demo-chat { height: 420px; overflow-y: auto; padding: 16px; }
.msg { margin-bottom: 14px; max-width: 88%; }
.msg.user { margin-left: auto; text-align: right; }
.msg-bubble {
  display: inline-block; padding: 10px 14px; border-radius: 12px;
  font-size: 0.88rem; text-align: left;
}
.msg.user .msg-bubble { background: var(--accent); color: #fff; border-bottom-right-radius: 4px; }
.msg.ai .msg-bubble { background: var(--surface2); border-bottom-left-radius: 4px; }
.msg.system .msg-bubble { background: rgba(239,68,68,.15); border: 1px solid var(--red); color: #fca5a5; }
.msg-meta { font-size: 11px; color: var(--muted); margin-top: 4px; }
.demo-input {
  display: flex; gap: 8px; padding: 12px; border-top: 1px solid var(--border);
}
.demo-input input {
  flex: 1; background: var(--bg); border: 1px solid var(--border);
  border-radius: 8px; padding: 10px 14px; color: var(--text); font-size: 0.9rem;
}
.demo-side { font-size: 0.88rem; }
.side-box {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 16px; margin-bottom: 16px;
}
.side-box h4 { font-size: 0.85rem; color: var(--muted); margin-bottom: 10px; }
.gate-bar { display: flex; gap: 8px; margin-top: 8px; }
.gate { flex: 1; text-align: center; padding: 8px; border-radius: 6px; font-size: 12px; font-weight: 600; opacity: .35; }
.gate.on.pass { background: rgba(34,197,94,.2); color: var(--green); opacity: 1; }
.gate.on.review { background: rgba(245,158,11,.2); color: var(--amber); opacity: 1; }
.gate.on.block { background: rgba(239,68,68,.2); color: var(--red); opacity: 1; }

.report-frame {
  width: 100%; height: 720px; border: 1px solid var(--border);
  border-radius: var(--radius); background: #fff;
}

@media (max-width: 900px) {
  .cards { grid-template-columns: 1fr; }
  .demo-layout { grid-template-columns: 1fr; }
  .hero h1 { font-size: 1.8rem; }
}