/* ================= 全局基础 & 统一 Header/Footer 样式 ================= */
        :root { 
            --bg-body: #f8fafc; --bg-card: #ffffff; 
            --primary: #0f172a; --accent-blue: #2563eb; --accent-cyan: #06b6d4; --accent-light: #e0f2fe; 
            --text-dark: #020617; --text-main: #334155; --text-muted: #64748b; 
            --border: #e2e8f0; --border-light: #f1f5f9;
        }
        * { box-sizing: border-box; }
        body { font-family: 'Inter', sans-serif; background: var(--bg-body); color: var(--text-main); line-height: 1.75; margin: 0; padding: 0; display: flex; flex-direction: column; min-height: 100vh; }
        h1, h2, h3, h4 { font-family: 'Outfit', sans-serif; color: var(--text-dark); letter-spacing: -0.02em; margin: 0;}
        a { text-decoration: none; color: var(--accent-blue); transition: 0.3s; }

        /* 统一 Header */
        header { background: rgba(255, 255, 255, 0.95); backdrop-filter: blur(16px); padding: 15px 45px; border-bottom: 1px solid var(--border); display: flex; justify-content: space-between; align-items: center; position: sticky; top: 0; z-index: 1000; box-shadow: 0 4px 20px rgba(0,0,0,0.02); }
        .logo img { max-height: 48px; }
        .nav-links { display: flex; gap: 32px; font-weight: 700; font-size: 0.95rem; align-items: center; }
        .nav-links > a { color: var(--text-dark); transition: color 0.2s; }
        .nav-links > a:hover { color: var(--accent-blue); }
        
        .nav-dropdown { position: relative; display: inline-block; }
        .nav-dropdown-toggle { color: var(--accent-blue) !important; display: flex; align-items: center; gap: 4px; cursor: pointer; padding: 10px 0; }
        .nav-dropdown-menu { position: absolute; top: 100%; left: 50%; transform: translateX(-50%) translateY(10px); background: #ffffff; min-width: 280px; box-shadow: 0 20px 40px rgba(15,23,42,0.08); border-radius: 16px; padding: 12px 0; opacity: 0; visibility: hidden; transition: all 0.3s ease; border: 1px solid var(--border); }
        .nav-dropdown:hover .nav-dropdown-menu { opacity: 1; visibility: visible; transform: translateX(-50%) translateY(0); }
        .nav-dropdown-menu a { display: block; padding: 12px 25px; color: var(--text-main); font-size: 0.95rem; font-weight: 600; }
        .nav-dropdown-menu a:hover { background: var(--bg-body); color: var(--accent-blue); padding-left: 32px; }

        /* 统一 面包屑 */
        .breadcrumbs-wrapper { background: #ffffff; border-bottom: 1px solid var(--border); width: 100%; }
        .breadcrumbs { max-width: 1300px; margin: 0 auto; padding: 12px 40px; font-size: 0.85rem; color: var(--text-muted); font-weight: 500;}
        .breadcrumbs span { margin: 0 10px; color: #cbd5e1; font-size: 0.75rem;}

        /* 统一 Footer */
        .site-footer { background: #020617; color: #94a3b8; padding: 40px 45px; text-align: center; margin-top: auto; }
        
        @media (max-width: 768px) {
            header { padding: 15px 20px; }
            .nav-links { display: none; }
            .breadcrumbs { padding: 0 24px; }
        }