/* roulang page: index */
:root {
            --primary-dark: #0F172A;
            --primary-cyan: #0D9488;
            --accent-blue: #2563EB;
            --accent-gold: #F59E0B;
            --bg-light: #F8FAFC;
            --card-border: #E2E8F0;
            --text-main: #334155;
            --text-title: #0F172A;
            --text-muted: #64748B;
        }
        
        * {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
            scroll-behavior: smooth;
        }

        body {
            font-family: 'Inter', system-ui, -apple-system, 'PingFang SC', 'Microsoft YaHei', sans-serif;
            color: var(--text-main);
            background-color: #FFFFFF;
            line-height: 1.65;
            -webkit-font-smoothing: antialiased;
        }

        .tabular-nums {
            font-feature-settings: "tnum";
            font-variant-numeric: tabular-nums;
        }

        .hero-video-mask {
            background: linear-gradient(135deg, rgba(15, 23, 42, 0.94) 0%, rgba(15, 23, 42, 0.85) 60%, rgba(13, 148, 136, 0.75) 100%);
        }

        .card-subtle {
            transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
            border: 1px solid var(--card-border);
            box-shadow: 0 4px 20px -2px rgba(15, 23, 42, 0.04);
        }
        .card-subtle:hover {
            transform: translateY(-4px);
            border-color: var(--primary-cyan);
            box-shadow: 0 12px 28px -4px rgba(13, 148, 136, 0.12);
        }

        .dark-concept-mesh {
            background-color: #030712;
            background-image: radial-gradient(rgba(13, 148, 136, 0.15) 1px, transparent 1px), radial-gradient(rgba(37, 99, 235, 0.1) 1px, transparent 1px);
            background-size: 32px 32px;
            background-position: 0 0, 16px 16px;
        }

        .badge-cyan {
            background: rgba(13, 148, 136, 0.1);
            color: #0D9488;
            border: 1px solid rgba(13, 148, 136, 0.25);
        }

        .badge-blue {
            background: rgba(37, 99, 235, 0.1);
            color: #2563EB;
            border: 1px solid rgba(37, 99, 235, 0.25);
        }

        /* 手风琴动效 */
        .faq-content {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.35s ease-out, opacity 0.3s ease;
            opacity: 0;
        }
        .faq-item.active .faq-content {
            max-height: 400px;
            opacity: 1;
        }
        .faq-item.active .faq-icon {
            transform: rotate(180deg);
        }