/* 全站一级导航：供不使用 styles.css 的独立页面复用 */
.site-head { background:#fff; border-bottom:1px solid #e6e9f0; position:sticky; top:0; z-index:30; }
.site-head-inner { max-width:1120px; width:100%; margin:0 auto; padding:0 20px;
  display:flex; align-items:center; justify-content:space-between; height:72px; gap:16px; }
.site-brand { display:flex; align-items:center; gap:10px; text-decoration:none; color:#101828; }
.site-logo { width:40px; height:40px; border-radius:11px; color:#fff; display:flex; align-items:center;
  justify-content:center; font-size:20px; background:linear-gradient(135deg,#22c55e,#16a34a); }
.site-name { font-size:19px; font-weight:700; letter-spacing:.3px; }
.site-nav { display:flex; gap:4px; flex-wrap:wrap; }
.site-nav a { padding:9px 15px; font-size:15px; color:#344054; text-decoration:none; border-radius:8px; position:relative; }
.site-nav a:hover { color:#f08a10; background:#fff8ee; }
.site-nav a.on { color:#111827; font-weight:600; }
.site-nav a.on::after { content:""; position:absolute; left:15px; right:15px; bottom:3px; height:3px;
  border-radius:2px; background:linear-gradient(90deg,#f7a52b,#f08a10); }
@media (max-width: 640px) {
  .site-head-inner { height:auto; padding:10px 14px; flex-wrap:wrap; }
  .site-logo { width:32px; height:32px; font-size:16px; border-radius:9px; }
  .site-name { font-size:16px; }
  .site-nav { gap:0; }
  .site-nav a { padding:8px 9px; font-size:13.5px; }
}

/* 窄屏（≤430px）：导航收窄，避免横向溢出 */
@media (max-width: 430px) {
  .site-head-inner { padding: 9px 12px; gap: 10px; }
  .site-nav a { padding: 7px 6px; font-size: 12.5px; }
  .site-nav a.on::after { left: 6px; right: 6px; bottom: 1px; height: 2px; }
  .site-name { font-size: 15px; }
  .site-logo { width: 30px; height: 30px; font-size: 15px; }
}
/* ≤480px：品牌占一行、导航占一行，彻底避免横向溢出 */
@media (max-width: 480px) {
  .site-head .site-head-inner { height: auto; padding: 9px 12px 7px; flex-wrap: wrap; row-gap: 5px; }
  .site-head .site-brand { flex: 1 0 100%; }
  .site-head .site-nav { flex: 1 0 100%; justify-content: space-between; gap: 0; }
  .site-head .site-nav a { padding: 6px 5px; font-size: 13px; }
  .site-head .site-nav a.on::after { left: 5px; right: 5px; bottom: 0; height: 2px; }
}

/* ===== 站点 logo 改为位图（新图标） ===== */
.site-logo { background: none; border-radius: 0; font-size: 0; object-fit: contain; flex: 0 0 auto; }
img.site-logo { display: block; }