/* 统一顶栏：与首页一致的蓝色顶栏 + 电脑端横向导航（内页使用，需在 style.css 之后加载） */
.site-header{height:64px;background:linear-gradient(100deg,#0f46e0,#2a7dff);border-bottom:0;box-shadow:0 6px 22px rgba(15,70,224,.25);color:#fff}
body.dark .site-header{background:linear-gradient(100deg,#0a2166,#1347c4);box-shadow:0 6px 22px rgba(0,0,0,.5)}
.site-header .header-inner{width:100%;max-width:1200px;margin:0 auto;height:64px;padding:0 14px;display:flex;align-items:center;gap:12px;color:#fff}
.site-header .menu-btn{width:38px;height:38px;padding:6px 4px;gap:5px}
.site-header .menu-btn span{width:24px;height:2.5px;background:#fff}
.site-header .brand{display:flex;align-items:center;gap:10px;color:#fff;min-width:0}
.site-header .brand-logo{width:40px;height:40px;border-radius:50%;display:grid;place-items:center;flex:0 0 auto;background:#fff;color:#0f46e0;font-weight:900;font-size:14px;letter-spacing:-.02em;font-style:italic;border:0;box-shadow:0 3px 10px rgba(0,20,100,.28)}
.site-header .brand-logo span{color:#ff8a1f}
.site-header .brand-logo:has(img){background:transparent;box-shadow:none;border-radius:0}
.site-header .brand-logo img{display:block;width:40px;height:40px;object-fit:contain;max-height:none;max-width:none;filter:drop-shadow(0 3px 6px rgba(0,20,100,.3))}
.site-header .brand-name{font-size:16px;font-weight:700;color:#fff;white-space:nowrap}
.main-nav{display:none;gap:2px;margin-left:12px}
.main-nav a{padding:9px 15px;border-radius:999px;font-size:14.5px;color:rgba(255,255,255,.82);transition:.2s;white-space:nowrap}
.main-nav a:hover{background:rgba(255,255,255,.14);color:#fff}
.main-nav a.on{background:rgba(255,255,255,.2);color:#fff;font-weight:600}
.site-header .header-actions{margin-left:auto;display:flex;align-items:center;gap:8px}
.site-header .theme-btn{display:grid;place-items:center;width:36px;height:36px;border:0;border-radius:50%;font-size:16px;color:#fff;background:rgba(255,255,255,.14)}
.site-header .header-btn{display:inline-flex;align-items:center;justify-content:center;height:36px;min-width:0;padding:0 13px;border-radius:999px;font-size:14px;font-weight:600;border:0}
.site-header .login-btn{border:1px solid rgba(255,255,255,.45);color:#fff;background:rgba(255,255,255,.1)}
.site-header .register-btn{background:#fff;color:#0f46e0;border-color:#fff}
@media(min-width:900px){
  .main-nav{display:flex}
  .site-header .menu-btn,.mobile-menu{display:none!important}
}

@media(max-width:899px){
  .site-header .header-inner{gap:8px;padding:0 10px}
  .site-header .menu-btn,.site-header .theme-btn,.mobile-menu{display:none!important}
  .site-header .brand{flex:1 1 auto;min-width:0;gap:8px}
  .site-header .brand-name{font-size:15px;overflow:hidden;text-overflow:ellipsis}
  .site-header .header-actions{gap:5px;flex:0 0 auto}
  .site-header .header-btn{height:32px;min-width:0;padding:0 10px;font-size:13px}
}
@media(min-width:900px){.site-header .back-home{display:none}}