/* roulang page: index */
:root {
            --academic-indigo: #0f172a;
            --academic-blue: #1e293b;
            --brand-teal: #0d9488;
            --brand-emerald: #059669;
            --bg-slate-light: #f8fafc;
            --border-subtle: rgba(226, 232, 240, 0.8);
        }
        body {
            font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Lantinghei SC", "Microsoft YaHei", sans-serif;
            color: #334155;
            background-color: #f8fafc;
            line-height: 1.75;
            margin: 0;
            padding: 0;
        }
        .text-academic-tight {
            line-height: 1.25;
            letter-spacing: -0.02em;
        }
        .subtle-border {
            border: 1px solid var(--border-subtle);
        }
        .card-lift {
            transition: transform 0.25s cubic-bezier(0.16, 1, 0.3, 1), box-shadow 0.25s cubic-bezier(0.16, 1, 0.3, 1);
        }
        .card-lift:hover {
            transform: translateY(-4px);
            box-shadow: 0 16px 32px -8px rgba(15, 23, 42, 0.08);
        }
        .glass-header {
            background-color: rgba(255, 255, 255, 0.94);
            backdrop-filter: blur(12px);
            -webkit-backdrop-filter: blur(12px);
        }
        .accordion-content {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.35s ease-out;
        }
        .accordion-content.open {
            max-height: 500px;
        }