:root {
  --bg: #f5f8ff;
  --card: #ffffff;
  --stroke: #d8e6ff;
  --accent: #0b5bd3;
  --accent-2: #2aa8ff;
  --text: #0b1b33;
  --muted: #5a6a85;
  --shadow: 0 16px 40px rgba(11, 27, 51, 0.12);
  --radius: 18px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
body {
  font-family: "Inter", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
}
a { text-decoration: none; color: inherit; }
img { max-width: 100%; display: block; }

.nav {
  position: sticky; top: 0; z-index: 1000;
  display: flex; align-items: center; justify-content: space-between;
  padding: 14px 28px; background: rgba(245,248,255,0.9);
  backdrop-filter: blur(10px); border-bottom: 1px solid var(--stroke);
}
.nav-logo { display: inline-flex; align-items: center; gap: 10px; font-weight: 700; }
.nav-logo-img { width: 32px; height: 32px; border-radius: 8px; }
.nav-links { display: flex; gap: 14px; flex-wrap: wrap; justify-content: flex-end; }
.nav-links a { color: var(--muted); font-size: 0.92rem; padding: 6px 10px; border-radius: 999px; }
.nav-links a.active, .nav-links a:hover { background: #e7f1ff; color: var(--text); }

.page-content { max-width: 1200px; margin: 0 auto; padding: 40px 24px 80px; }
.page-hero {
  display: grid; grid-template-columns: 1.1fr 0.9fr; gap: 32px; align-items: center;
  padding: 40px; border-radius: 28px;
  background: linear-gradient(135deg, #e9f2ff, #ffffff);
  border: 1px solid var(--stroke);
  box-shadow: var(--shadow);
}
.hero-left h1 { font-size: 2.6rem; margin: 10px 0 12px; }
.hero-left p { color: var(--muted); }
.hero-badge {
  display: inline-flex; gap: 8px; align-items: center;
  background: #e1efff; color: #0b4aa8; border: 1px solid #cfe3ff;
  padding: 6px 14px; border-radius: 999px; font-size: 0.85rem;
}
.hero-actions { display: flex; gap: 12px; margin: 20px 0; flex-wrap: wrap; }
.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #fff; padding: 12px 22px; border-radius: 999px; font-weight: 600;
}
.btn-ghost { border: 1px solid var(--stroke); padding: 12px 22px; border-radius: 999px; color: var(--text); background: #fff; }
.hero-stats { display: flex; gap: 20px; color: var(--muted); }
.hero-stats strong { color: var(--text); display: block; font-size: 1.2rem; }
.hero-card {
  background: #ffffff; border: 1px solid var(--stroke); border-radius: var(--radius);
  padding: 24px; box-shadow: var(--shadow);
}
.hero-card-title { font-weight: 700; margin-bottom: 12px; }
.hero-card ul { list-style: none; display: grid; gap: 8px; color: var(--muted); }
.hero-card-footer { margin-top: 16px; font-size: 0.9rem; color: var(--muted); }

.section-head { text-align: center; margin: 50px 0 30px; }
.section-head h2 { font-size: 2rem; }
.section-head p { color: var(--muted); margin-top: 8px; }

.dl-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.dl-card {
  background: #ffffff; border: 1px solid var(--stroke); border-radius: var(--radius);
  padding: 24px; position: relative; box-shadow: 0 10px 24px rgba(11,27,51,0.06);
}
.dl-card.featured { border-color: #bcd7ff; }
.dl-card-badge {
  position: absolute; top: 16px; right: 16px; background: var(--accent);
  color: #fff; padding: 4px 10px; border-radius: 999px; font-size: 0.75rem;
}
.dl-card-icon { font-size: 2rem; color: var(--accent); margin-bottom: 12px; }
.dl-version { color: var(--muted); font-size: 0.9rem; }
.dl-desc { margin: 8px 0 12px; color: var(--muted); }
.dl-features { list-style: none; display: grid; gap: 6px; color: var(--muted); margin-bottom: 16px; }
.dl-btn {
  display: inline-flex; gap: 8px; align-items: center;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #fff; padding: 10px 16px; border-radius: 999px; font-weight: 600;
}

.advantage-section { margin-top: 60px; }
.advantage-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px; }
.advantage-item {
  background: #ffffff; border: 1px solid var(--stroke); border-radius: var(--radius);
  padding: 18px 20px; display: flex; gap: 12px; align-items: flex-start;
  box-shadow: 0 8px 16px rgba(11,27,51,0.05);
}
.advantage-item i { font-size: 1.3rem; color: var(--accent); margin-top: 4px; }
.advantage-item h3 { font-size: 1rem; margin-bottom: 6px; }
.advantage-item p { color: var(--muted); font-size: 0.92rem; }

.version-history { margin-top: 60px; }
.timeline { display: grid; gap: 20px; }
.timeline-item { display: grid; grid-template-columns: 20px 1fr; gap: 16px; }
.timeline-dot { width: 12px; height: 12px; border-radius: 50%; background: var(--accent); margin-top: 8px; }
.timeline-content {
  background: #ffffff; border: 1px solid var(--stroke); border-radius: var(--radius);
  padding: 18px 22px; box-shadow: 0 8px 18px rgba(11,27,51,0.05);
}
.timeline-head { display: flex; gap: 12px; align-items: center; margin-bottom: 10px; }
.version-num { font-weight: 700; color: var(--accent); }
.version-date { color: var(--muted); }
.version-tag { background: #e1efff; color: #0b4aa8; padding: 2px 8px; border-radius: 999px; font-size: 0.75rem; }
.timeline-content ul { list-style: none; display: grid; gap: 6px; color: var(--muted); }

.safe-section { margin-top: 60px; }
.safe-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.safe-item {
  background: #ffffff; border: 1px solid var(--stroke); border-radius: var(--radius);
  padding: 16px; display: flex; gap: 10px; align-items: center; justify-content: center;
  color: var(--muted); box-shadow: 0 8px 16px rgba(11,27,51,0.05);
}

footer {
  text-align: center; padding: 30px 16px 50px; color: var(--muted);
}
.footer-brand { font-weight: 700; color: var(--text); margin-bottom: 6px; }
.footer-info { margin-bottom: 6px; }

@media (max-width: 960px) {
  .page-hero { grid-template-columns: 1fr; }
  .dl-grid { grid-template-columns: 1fr; }
  .safe-grid { grid-template-columns: repeat(2, 1fr); }
  .advantage-grid { grid-template-columns: 1fr; }
}
@media (max-width: 640px) {
  .nav-links { display: none; }
  .hero-left h1 { font-size: 2rem; }
  .hero-stats { flex-direction: column; gap: 10px; }
  .safe-grid { grid-template-columns: 1fr; }
}