/* roulang page: index */
:root {
            --bg-base: #FFFFFF;
            --bg-sub: #F8F9FA;
            --bg-dark: #0A0D14;
            --text-title: #0F172A;
            --text-body: #475569;
            --text-muted: #94A3B8;
            --brand-primary: #0052FF;
            --brand-accent: #00D18F;
            --border-light: #E2E8F0;
        }

        html {
            scroll-behavior: smooth;
        }

        body {
            font-family: 'PingFang SC', 'Noto Sans SC', -apple-system, Inter, sans-serif;
            color: var(--text-body);
            background-color: var(--bg-base);
            margin: 0;
            padding: 0;
            overflow-x: hidden;
            -webkit-font-smoothing: antialiased;
        }

        .num-tabular {
            font-variant-numeric: tabular-nums;
            letter-spacing: -0.02em;
        }

        .hero-banner-overlay {
            background: linear-gradient(180deg, rgba(10, 13, 20, 0.72) 0%, rgba(10, 13, 20, 0.92) 100%);
        }

        .dark-glass-nav {
            background: rgba(10, 13, 20, 0.85);
            backdrop-filter: blur(12px);
            -webkit-backdrop-filter: blur(12px);
        }

        .card-interactive {
            transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
        }

        .card-interactive:hover {
            transform: translateY(-4px);
            box-shadow: 0 12px 28px -6px rgba(15, 23, 42, 0.08);
        }

        details > summary {
            list-style: none;
        }
        details > summary::-webkit-details-marker {
            display: none;
        }
        details[open] summary svg {
            transform: rotate(180deg);
        }

        .accordion-content {
            transition: all 0.2s ease-in-out;
        }