:root {
  --bg: #f8fafc;
  --card: #ffffff;
  --text: #0f172a;
  --muted: #64748b;
  --primary: #2563eb;
  --border: #e2e8f0;
}
* { box-sizing: border-box; }
body { margin: 0; font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif; background: var(--bg); color: var(--text); }
a { color: inherit; text-decoration: none; }
a, .btn, .nav-link, .nav-dropdown-link, .logo { cursor: pointer; }
.container { max-width: 1140px; margin: 0 auto; padding: 0 24px; }
.topbar { background: #0f172a; color: #e2e8f0; font-size: 12px; }
.topbar-inner { display: flex; justify-content: space-between; align-items: center; padding: 8px 0; }
.site-header { background: #fff; border-bottom: 1px solid var(--border); position: sticky; top: 0; z-index: 10; }
.header-inner { display: flex; align-items: center; justify-content: space-between; padding: 16px 0; gap: 24px; }
.logo { display: flex; align-items: center; gap: 8px; font-size: 18px; font-weight: 600; }
.logo-badge { background: var(--primary); color: #fff; font-size: 12px; padding: 2px 6px; border-radius: 4px; }
.nav { display: flex; align-items: center; gap: 16px; flex-wrap: wrap; position: relative; }
.nav-item { position: relative; }
.nav-link { font-size: 14px; color: var(--muted); padding: 6px 0; border-bottom: 2px solid transparent; display: inline-flex; }
.nav-link:hover { color: var(--primary); border-bottom-color: var(--primary); }
.nav-dropdown { position: absolute; top: calc(100% + 12px); left: 0; min-width: 180px; background: #fff; border: 1px solid var(--border); border-radius: 10px; box-shadow: 0 10px 24px rgba(15, 23, 42, 0.12); padding: 10px; opacity: 0; visibility: hidden; transform: translateY(8px); transition: all 0.2s ease; z-index: 20; }
.nav-item:hover .nav-dropdown { opacity: 1; visibility: visible; transform: translateY(0); }
.nav-dropdown-list { display: grid; gap: 6px; }
.nav-dropdown-link { padding: 6px 8px; border-radius: 6px; color: var(--text); font-size: 13px; }
.nav-dropdown-link:hover { background: #f1f5f9; color: var(--primary); }
.btn { display: inline-flex; align-items: center; justify-content: center; padding: 10px 18px; border-radius: 8px; font-size: 14px; border: 1px solid var(--primary); gap: 6px; }
.btn.primary { background: var(--primary); color: #fff; }
.btn.ghost { color: var(--primary); background: transparent; }
.btn.light { background: #eef2ff; border-color: transparent; color: var(--primary); }
.site-main { min-height: 60vh; }
.site-footer { margin-top: 40px; padding: 32px 0 16px; border-top: 1px solid var(--border); background: #fff; }
.footer-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 20px; }
.footer-title { font-weight: 600; margin-bottom: 8px; }
.footer-text { color: var(--muted); font-size: 12px; line-height: 1.6; }
.footer-links { list-style: none; padding: 0; margin: 0; display: grid; gap: 6px; }
.footer-bottom { margin-top: 16px; padding-top: 12px; border-top: 1px solid var(--border); font-size: 12px; color: var(--muted); text-align: center; }