/* roulang page: index */
:root {
            --primary-grad: linear-gradient(135deg, #4F46E5 0%, #06B6D4 100%);
            --accent-glow: rgba(79, 70, 229, 0.25);
        }
        html {
            scroll-behavior: smooth;
            font-family: system-ui, -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
        }
        .font-num {
            font-family: "DIN Alternate", "Inter", "Roboto", -apple-system, sans-serif;
        }
        .grad-text {
            background: var(--primary-grad);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
        }
        .grad-bg {
            background: var(--primary-grad);
        }
        .card-hover {
            transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
        }
        .card-hover:hover {
            transform: translateY(-4px);
            box-shadow: 0 15px 35px -10px var(--accent-glow);
        }
        .details-arrow {
            transition: transform 0.2s ease-in-out;
        }
        details[open] .details-arrow {
            transform: rotate(180deg);
        }
        details > summary::-webkit-details-marker {
            display: none;
        }