/* roulang page: index */
:root {
            --primary-teal: #00c9a7;
            --electric-cyan: #0ea5e9;
            --dark-titanium: #0f172a;
            --deep-space: #0a0f1e;
            --surface-cold: #f8fafc;
            --surface-muted: #f1f5f9;
            --text-heading: #0f172a;
            --text-body: #475569;
        }

        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
            color: var(--text-body);
            background-color: #ffffff;
            overflow-x: hidden;
        }

        ::selection {
            background-color: var(--primary-teal);
            color: #ffffff;
        }

        ::-webkit-scrollbar {
            width: 8px;
        }
        ::-webkit-scrollbar-track {
            background: #f1f5f9;
        }
        ::-webkit-scrollbar-thumb {
            background: #94a3b8;
            border-radius: 4px;
        }
        ::-webkit-scrollbar-thumb:hover {
            background: #64748b;
        }

        .hero-slide {
            transition: opacity 0.8s ease-in-out, transform 0.8s ease-in-out;
        }
        .hero-slide.active {
            opacity: 1;
            transform: scale(1);
            pointer-events: auto;
        }
        .hero-slide.inactive {
            opacity: 0;
            transform: scale(1.03);
            pointer-events: none;
        }

        .glass-nav {
            background: rgba(15, 23, 42, 0.88);
            backdrop-filter: blur(12px);
            -webkit-backdrop-filter: blur(12px);
        }

        .dark-pattern-grid {
            background-image: radial-gradient(rgba(14, 165, 233, 0.15) 1px, transparent 1px);
            background-size: 32px 32px;
        }

        .tech-card {
            transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
        }
        .tech-card:hover {
            transform: translateY(-4px);
            box-shadow: 0 16px 32px -8px rgba(0, 201, 167, 0.12), 0 8px 16px -6px rgba(15, 23, 42, 0.08);
            border-color: rgba(0, 201, 167, 0.5);
        }

        .accordion-content {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.35s ease-out, opacity 0.3s ease;
            opacity: 0;
        }
        .accordion-content.open {
            opacity: 1;
        }