/* roulang page: index */
:root {
            --primary-navy: #0F2C59;
            --accent-blue: #0066FF;
            --tech-cyan: #00B4D8;
            --bg-light: #F8FAFC;
            --text-main: #1E293B;
            --text-muted: #64748B;
            --card-border: rgba(226, 232, 240, 0.9);
            --shadow-subtle: 0 4px 20px -2px rgba(15, 44, 89, 0.06);
            --shadow-hover: 0 16px 32px -4px rgba(0, 102, 255, 0.12);
        }
        * { box-sizing: border-box; margin: 0; padding: 0; }
        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
            background-color: var(--bg-light);
            color: var(--text-main);
            line-height: 1.6;
            scroll-behavior: smooth;
        }
        .custom-card {
            background: #FFFFFF;
            border: 1px solid var(--card-border);
            border-radius: 0.75rem;
            box-shadow: var(--shadow-subtle);
            transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
        }
        .custom-card:hover {
            box-shadow: var(--shadow-hover);
            transform: translateY(-3px);
            border-color: rgba(0, 102, 255, 0.3);
        }
        .chip-gradient {
            background: linear-gradient(135deg, #0F2C59 0%, #173B75 100%);
        }
        .dark-section {
            background-color: #0B192C;
            color: #F8FAFC;
        }
        .accordion-content {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.35s ease-out;
        }
        .accordion-item.active .accordion-content {
            max-height: 280px;
        }
        .accordion-item.active .accordion-icon {
            transform: rotate(180deg);
        }
        .focus-outline:focus-visible {
            outline: 2px solid var(--accent-blue);
            outline-offset: 2px;
        }
        .glass-nav {
            background: rgba(255, 255, 255, 0.95);
            backdrop-filter: blur(12px);
        }