/* 统一头部导航 */
        nav {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 20px 5%;
            position: fixed;
            width: 100%;
            top: 0;
            z-index: 100;
            backdrop-filter: blur(15px);
            background: rgba(15, 23, 42, 0.8);
            border-bottom: 1px solid var(--border);
            height: 80px;
            align-items: center;
            padding: 0 5%;
        }
        .logo {
            font-weight: 800;
            font-size: 1.5rem;
            background: var(--brand-gradient);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            text-decoration: none;
            letter-spacing: -1px;
        }
        .nav-links { display: flex; gap: 20px; align-items: center; }
        .nav-links a {
            text-decoration: none;
            color: var(--text-muted);
            font-weight: 600;
            font-size: 1.00rem;
            transition: 0.3s;
        }
        .nav-links a:hover { color: var(--brand-color); }
        .nav-links a.active { color: var(--brand-color); font-weight: 800; }
        .btn-primary {
            background: var(--brand-gradient);
            padding: 10px 18px;
            border-radius: 10px;
            color: white;
            text-decoration: none;
            font-weight: 700;
            font-size: 1.05rem;
            box-shadow: 0 4px 15px rgba(99, 102, 241, 0.2);
        }

        .btn-login {
            color: var(--text-main);
            text-decoration: none;
            font-size: 1rem;
            font-weight: 700;
            padding: 10px 24px;      /* 增加左右内边距，让按钮更宽，更像按钮 */
            margin-right: 15px;
            border-radius: 12px;     /* 圆角与主按钮保持一致 */

            /* 核心样式：背景微亮 + 细边框 */
            background: rgba(255, 255, 255, 0.05);
            border: 1px solid rgba(255, 255, 255, 0.15);

            display: inline-flex;
            align-items: center;
            justify-content: center;
            transition: all 0.3s cubic-bezier(0.23, 1, 0.32, 1);
            backdrop-filter: blur(5px); /* 增加一点毛玻璃效果 */
        }

        /* 悬停效果：边框变色，阴影增强 */
        .btn-login:hover {
            color: #ffffff;
            background: rgba(255, 255, 255, 0.1);
            border-color: var(--brand-color); /* 悬停时边框亮起品牌色 */
            box-shadow: 0 8px 20px rgba(0, 0, 0, 0.2);
            transform: translateY(-2px); /* 向上浮动 */
        }

        /* 点击效果：按下缩放 */
        .btn-login:active {
            transform: translateY(0) scale(0.95);
        }

        footer {
            text-align: center;
            padding: 60px;
            color: var(--text-muted);
            font-size: 0.85rem;
            border-top: 1px solid rgba(255,255,255,0.05);
            background: rgba(0,0,0,0.2);
        }