/* roulang page: index */
:root {
            --primary: #6C3CE1;
            --secondary: #00E5FF;
            --bg-start: #0B0E17;
            --bg-end: #131824;
            --surface: rgba(255, 255, 255, 0.04);
            --border-light: rgba(255, 255, 255, 0.08);
            --border-glow: rgba(255, 255, 255, 0.2);
            --text-primary: #FFFFFF;
            --text-secondary: #B0B8CC;
            --text-muted: #6E7686;
            --radius-md: 12px;
            --radius-lg: 16px;
            --radius-xl: 20px;
            --shadow-card: 0 20px 40px rgba(108, 60, 225, 0.15);
            --shadow-glow: 0 0 30px rgba(0, 229, 255, 0.3);
            --font-sans: "Inter", "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
        }

        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        html {
            scroll-behavior: smooth;
            background: var(--bg-start);
        }

        body {
            font-family: var(--font-sans);
            background: linear-gradient(135deg, var(--bg-start) 0%, var(--bg-end) 100%);
            color: var(--text-primary);
            line-height: 1.75;
            min-height: 100vh;
            -webkit-font-smoothing: antialiased;
        }

        .container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 24px;
        }

        @media (max-width: 640px) {
            .container {
                padding: 0 16px;
            }
        }

        /* 导航栏 */
        .navbar {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            z-index: 50;
            background: rgba(11, 14, 23, 0.85);
            backdrop-filter: blur(20px);
            -webkit-backdrop-filter: blur(20px);
            border-bottom: 1px solid rgba(255, 255, 255, 0.06);
            height: 72px;
            display: flex;
            align-items: center;
        }

        @media (max-width: 640px) {
            .navbar {
                height: 60px;
            }
        }

        .nav-container {
            display: flex;
            align-items: center;
            justify-content: space-between;
            width: 100%;
        }

        .logo {
            font-weight: 800;
            font-size: 1.5rem;
            letter-spacing: -0.02em;
            color: var(--text-primary);
            text-decoration: none;
            display: flex;
            align-items: center;
            gap: 8px;
        }
        .logo span {
            background: linear-gradient(135deg, var(--primary), var(--secondary));
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
        }

        .nav-links {
            display: flex;
            gap: 8px;
            align-items: center;
        }

        .nav-links a {
            color: var(--text-primary);
            text-decoration: none;
            font-weight: 500;
            padding: 8px 16px;
            border-radius: 8px;
            transition: all 0.2s ease;
            font-size: 0.95rem;
        }

        .nav-links a:hover {
            background: rgba(255, 255, 255, 0.06);
            color: var(--secondary);
        }

        .nav-links a.active {
            color: var(--secondary);
            border-bottom: 2px solid var(--secondary);
            background: transparent;
        }

        .hamburger {
            display: none;
            flex-direction: column;
            gap: 5px;
            cursor: pointer;
            background: transparent;
            border: none;
            padding: 8px;
        }

        .hamburger span {
            display: block;
            width: 24px;
            height: 2px;
            background: var(--secondary);
            transition: 0.3s;
            border-radius: 4px;
        }

        .mobile-menu {
            display: none;
            position: fixed;
            top: 72px;
            left: 0;
            width: 100%;
            background: rgba(11, 14, 23, 0.96);
            backdrop-filter: blur(25px);
            -webkit-backdrop-filter: blur(25px);
            flex-direction: column;
            padding: 24px;
            gap: 12px;
            border-bottom: 1px solid rgba(255,255,255,0.06);
            z-index: 40;
        }
        .mobile-menu a {
            color: white;
            text-decoration: none;
            font-size: 1.2rem;
            font-weight: 500;
            padding: 12px 0;
            border-bottom: 1px solid rgba(255,255,255,0.05);
        }

        @media (max-width: 768px) {
            .nav-links {
                display: none;
            }
            .hamburger {
                display: flex;
            }
            .mobile-menu.active {
                display: flex;
            }
        }

        /* 板块间距 */
        section {
            padding: 120px 0;
        }
        @media (max-width: 1024px) {
            section {
                padding: 80px 0;
            }
        }
        @media (max-width: 640px) {
            section {
                padding: 60px 0;
            }
        }

        /* 卡片系统 */
        .glass-card {
            background: var(--surface);
            backdrop-filter: blur(20px);
            -webkit-backdrop-filter: blur(20px);
            border: 1px solid var(--border-light);
            border-radius: var(--radius-lg);
            transition: all 0.3s ease;
        }
        .glass-card:hover {
            border-color: var(--border-glow);
            transform: translateY(-4px);
            box-shadow: var(--shadow-card);
        }

        .highlight-card {
            border: 1px solid rgba(0,229,255,0.4);
            box-shadow: 0 0 20px rgba(0,229,255,0.2);
            background: rgba(255,255,255,0.06);
        }

        /* 按钮 */
        .btn-primary {
            background: linear-gradient(135deg, var(--primary), var(--secondary));
            color: white;
            font-weight: 600;
            padding: 14px 32px;
            border-radius: 12px;
            display: inline-block;
            text-decoration: none;
            transition: all 0.25s ease;
            border: none;
            cursor: pointer;
            box-shadow: 0 4px 20px rgba(108,60,225,0.3);
        }
        .btn-primary:hover {
            box-shadow: 0 0 30px rgba(108,60,225,0.6);
            transform: translateY(-2px);
        }
        .btn-secondary {
            background: transparent;
            border: 1px solid var(--secondary);
            color: var(--secondary);
            font-weight: 600;
            padding: 14px 32px;
            border-radius: 12px;
            display: inline-block;
            text-decoration: none;
            transition: 0.25s;
            cursor: pointer;
        }
        .btn-secondary:hover {
            background: rgba(0,229,255,0.1);
            box-shadow: 0 0 15px rgba(0,229,255,0.3);
        }

        /* 输入框 */
        .glass-input {
            background: rgba(255,255,255,0.04);
            border: 1px solid rgba(255,255,255,0.1);
            border-radius: 10px;
            padding: 14px 16px;
            color: white;
            width: 100%;
            transition: 0.2s;
            backdrop-filter: blur(10px);
        }
        .glass-input:focus {
            outline: none;
            border-color: var(--secondary);
            box-shadow: 0 0 10px rgba(0,229,255,0.2);
        }

        /* FAQ 手风琴 */
        .faq-item {
            background: rgba(255,255,255,0.03);
            backdrop-filter: blur(10px);
            border-radius: 12px;
            margin-bottom: 12px;
            border: 1px solid rgba(255,255,255,0.05);
        }
        .faq-question {
            padding: 20px;
            font-weight: 600;
            cursor: pointer;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        .faq-answer {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.4s ease, padding 0.3s;
            padding: 0 20px;
            color: #B0B8CC;
        }
        .faq-item.open .faq-answer {
            max-height: 200px;
            padding: 0 20px 20px;
        }
        .faq-icon {
            font-size: 1.5rem;
            transition: 0.3s;
            color: var(--secondary);
        }