/* roulang page: index */
:root {
            --bg-body: #0A0F1D;
            --bg-card: #111827;
            --primary: #10B981;
            --accent: #F59E0B;
            --text-main: #F9FAFB;
            --text-muted: #9CA3AF;
            --border: rgba(255, 255, 255, 0.08);
            --radius: 12px;
            --shadow: 0 4px 20px -2px rgba(0, 0, 0, 0.5);
        }
        * { margin: 0; padding: 0; box-sizing: border-box; }
        body { font-family: system-ui, -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif; background: var(--bg-body); color: var(--text-main); line-height: 1.65; }
        a { text-decoration: none; color: inherit; transition: 0.3s; }
        ul { list-style: none; }
        .container { max-width: 1280px; margin: 0 auto; padding: 0 24px; }
        
        /* Header */
        header { position: sticky; top: 0; z-index: 100; background: rgba(10, 15, 29, 0.9); backdrop-filter: blur(10px); border-bottom: 1px solid var(--border); }
        .top-bar { font-size: 12px; display: flex; justify-content: space-between; padding: 8px 24px; color: var(--text-muted); border-bottom: 1px solid var(--border); }
        .nav-bar { display: flex; align-items: center; justify-content: space-between; padding: 16px 24px; }
        .logo { font-size: 20px; font-weight: 700; color: var(--primary); }
        .nav-links { display: flex; gap: 32px; font-size: 14px; }
        .btn-cta { background: var(--primary); color: #000; padding: 8px 20px; border-radius: 6px; font-weight: 600; }
        
        /* Hero */
        .hero { padding: 100px 0; background: linear-gradient(rgba(10,15,29,0.8), rgba(10,15,29,0.8)), url('/assets/images/backpic/back-1.jpg') center/cover; }
        .hero-content { max-width: 800px; }
        h1 { font-size: 48px; line-height: 1.2; margin-bottom: 24px; }
        .tag-group { display: flex; gap: 12px; margin-bottom: 32px; }
        .tag { border: 1px solid var(--primary); color: var(--primary); padding: 4px 12px; border-radius: 4px; font-size: 14px; }
        
        /* Sections */
        section { padding: 80px 0; border-bottom: 1px solid var(--border); }
        .sec-title { font-size: 36px; margin-bottom: 48px; text-align: center; }
        
        /* Grid Components */
        .grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
        .card { background: var(--bg-card); padding: 32px; border-radius: var(--radius); border: 1px solid var(--border); transition: 0.3s; }
        .card:hover { transform: translateY(-5px); border-color: var(--primary); }
        
        /* Metrics */
        .metrics-bar { display: grid; grid-template-columns: repeat(4, 1fr); gap: 40px; text-align: center; padding: 60px 0; }
        .metric-val { font-family: "JetBrains Mono", monospace; font-size: 40px; color: var(--primary); font-weight: 700; }
        
        /* FAQ */
        .faq-item { border-bottom: 1px solid var(--border); padding: 24px 0; cursor: pointer; }
        .faq-answer { display: none; padding-top: 16px; color: var(--text-muted); }
        
        /* Footer */
        footer { padding: 40px 0; background: #050812; text-align: center; font-size: 14px; color: var(--text-muted); }
        
        @media (max-width: 768px) {
            .nav-links { display: none; }
            .grid-3 { grid-template-columns: 1fr; }
            .metrics-bar { grid-template-columns: 1fr 1fr; }
            h1 { font-size: 32px; }
        }