:root {
  --bg: #ffffff;
  --bg-alt: #f6f8fb;
  --text: #1a1f29;
  --muted: #5b6472;
  --accent: #2563eb;
  --accent-2: #7c3aed;
  --border: #e5e9f0;
  --radius: 14px;
  --maxw: 1080px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0e1117;
    --bg-alt: #151a23;
    --text: #e8ecf3;
    --muted: #9aa4b2;
    --border: #232b38;
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", Roboto, Helvetica, Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

.container {
  width: 100%;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 20px;
}

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

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--border);
}
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}
.brand { font-weight: 700; font-size: 18px; color: var(--text); }
.nav-links a { margin-left: 22px; color: var(--muted); font-size: 15px; }

/* Hero */
.hero {
  padding: 96px 0 80px;
  background:
    radial-gradient(1200px 500px at 70% -10%, color-mix(in srgb, var(--accent) 18%, transparent), transparent),
    radial-gradient(900px 400px at 10% 10%, color-mix(in srgb, var(--accent-2) 14%, transparent), transparent);
}
.eyebrow {
  display: inline-block;
  font-size: 13px;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 12%, transparent);
  padding: 4px 12px;
  border-radius: 999px;
  margin: 0 0 18px;
}
.hero h1 {
  font-size: clamp(30px, 5vw, 52px);
  line-height: 1.15;
  margin: 0 0 18px;
  letter-spacing: -0.02em;
}
.lead { font-size: clamp(16px, 2.2vw, 20px); color: var(--muted); max-width: 640px; margin: 0 0 30px; }
.cta-row { display: flex; gap: 14px; flex-wrap: wrap; }

.btn {
  display: inline-block;
  padding: 12px 24px;
  border-radius: 10px;
  font-weight: 600;
  font-size: 15px;
  transition: transform .08s ease, opacity .2s ease;
}
.btn:hover { text-decoration: none; transform: translateY(-1px); }
.btn-primary { background: var(--accent); color: #fff; }
.btn-ghost { border: 1px solid var(--border); color: var(--text); }

/* Sections */
.section { padding: 72px 0; }
.section-alt { background: var(--bg-alt); }
.section h2 { font-size: clamp(24px, 3.5vw, 34px); margin: 0 0 16px; }
.section p { color: var(--muted); max-width: 720px; }

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
  margin-top: 28px;
}
.card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
}
.card h3 { margin: 0 0 8px; font-size: 19px; }
.card p { margin: 0; font-size: 15px; }

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 28px 0;
  color: var(--muted);
  font-size: 14px;
}

@media (max-width: 600px) {
  .nav-links a { margin-left: 14px; font-size: 14px; }
  .hero { padding: 64px 0 56px; }
  .section { padding: 52px 0; }
}