/* roulang page: index */
:root {
            --primary: #1E3A8A;
            --primary-accent: #6366F1;
            --amber-accent: #F59E0B;
            --bg-light: #F8FAFC;
            --bg-dark: #0F172A;
            --text-main: #1E293B;
            --text-muted: #64748B;
        }
        body {
            color: var(--text-main);
            background-color: #FFFFFF;
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
            line-height: 1.8;
        }
        .text-tight {
            letter-spacing: -0.02em;
        }
        .wave-bar {
            animation: soundWave 1.4s ease-in-out infinite alternate;
        }
        @keyframes soundWave {
            0% { height: 15%; }
            100% { height: 95%; }
        }
        .accordion-content {
            transition: max-height 0.3s cubic-bezier(0, 1, 0, 1), opacity 0.3s ease;
            max-height: 0;
            overflow: hidden;
            opacity: 0;
        }
        .accordion-item.active .accordion-content {
            max-height: 500px;
            opacity: 1;
            transition: max-height 0.35s ease-in-out, opacity 0.3s ease;
        }
        .accordion-item.active .accordion-icon {
            transform: rotate(180deg);
        }