/* roulang page: index */
:root {
            --color-primary: #0D131A;
            --color-steel: #1E2A38;
            --color-cobalt: #244B7A;
            --color-gold: #C5A467;
            --color-emerald: #00A86B;
            --color-bg: #F8FAFC;
        }
        * { box-sizing: border-box; }
        body {
            font-family: system-ui, -apple-system, "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
            background-color: var(--color-bg);
            color: #1f2937;
            line-height: 1.75;
            scroll-behavior: smooth;
        }
        .hero-bg {
            background: linear-gradient(135deg, rgba(13, 19, 26, 0.94) 0%, rgba(30, 42, 56, 0.90) 100%), url('/assets/images/171e07b50a47c65d.webp') center/cover no-repeat;
        }
        .code-box {
            background-color: #0b0f14;
            border: 1px solid #2d3748;
            box-shadow: inset 0 0 15px rgba(0,0,0,0.5);
        }
        .feature-card {
            transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
        }
        .feature-card:hover {
            transform: translateY(-4px);
            box-shadow: 0 12px 28px -4px rgba(13, 19, 26, 0.08);
            border-color: var(--color-gold);
        }
        .faq-content {
            transition: max-height 0.3s ease-out, opacity 0.3s ease;
            max-height: 0;
            overflow: hidden;
            opacity: 0;
        }
        .faq-item.active .faq-content {
            max-height: 240px;
            opacity: 1;
        }
        .faq-item.active .faq-icon {
            transform: rotate(180deg);
        }