/* roulang page: index */
:root {
            --primary: #0284C7;
            --primary-dark: #0369A1;
            --secondary: #0D9488;
            --bg-base: #F8FAFC;
            --surface: #FFFFFF;
            --text-main: #0F172A;
            --text-muted: #334155;
            --text-light: #64748B;
            --border-color: #E2E8F0;
            --radius-md: 0.5rem;
            --radius-xl: 0.75rem;
            --shadow-subtle: 0 4px 20px -2px rgba(15, 23, 42, 0.05);
            --shadow-hover: 0 12px 28px -6px rgba(15, 23, 42, 0.1);
        }

        html {
            scroll-behavior: smooth;
            font-family: system-ui, -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
            background-color: var(--bg-base);
            color: var(--text-main);
            overflow-x: hidden;
        }

        body {
            line-height: 1.65;
            margin: 0;
            padding: 0;
            overflow-x: hidden;
        }

        .section-padding {
            padding-top: 4.5rem;
            padding-bottom: 4.5rem;
        }

        @media (min-width: 1024px) {
            .section-padding {
                padding-top: 6rem;
                padding-bottom: 6rem;
            }
        }

        .card-custom {
            background-color: var(--surface);
            border: 1px solid var(--border-color);
            border-radius: var(--radius-xl);
            transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
        }

        .card-custom:hover {
            transform: translateY(-4px);
            box-shadow: var(--shadow-hover);
            border-color: #CBD5E1;
        }

        .btn-primary {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            background-color: var(--primary);
            color: #FFFFFF;
            font-weight: 500;
            border-radius: var(--radius-md);
            padding: 0.75rem 1.5rem;
            transition: all 0.2s ease;
        }

        .btn-primary:hover {
            background-color: var(--primary-dark);
            transform: translateY(-1px);
        }

        .btn-outline {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            background-color: transparent;
            color: var(--text-main);
            border: 1px solid var(--border-color);
            font-weight: 500;
            border-radius: var(--radius-md);
            padding: 0.75rem 1.5rem;
            transition: all 0.2s ease;
        }

        .btn-outline:hover {
            border-color: var(--primary);
            color: var(--primary);
            background-color: #FFFFFF;
        }

        /* 原生 details 手风琴微动效 */
        details summary {
            list-style: none;
            cursor: pointer;
        }
        details summary::-webkit-details-marker {
            display: none;
        }
        details[open] .faq-icon {
            transform: rotate(45deg);
        }