/* roulang page: index */
:root {
            --primary: #4F46E5;
            --accent: #06B6D4;
            --dark: #0F172A;
            --light: #F8FAFC;
            --text-main: #0F172A;
            --text-gray: #334155;
            --text-muted: #64748B;
            --white: #FFFFFF;
            --radius: 12px;
            --shadow: 0 10px 25px -5px rgba(0,0,0,0.05);
            --spacing: 80px;
        }

        * { margin: 0; padding: 0; box-sizing: border-box; }
        body { font-family: system-ui, -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif; line-height: 1.65; color: var(--text-gray); background: var(--light); }
        .container { max-width: 1280px; margin: 0 auto; padding: 0 20px; }
        
        /* Header */
        header { position: sticky; top: 0; z-index: 1000; background: rgba(255,255,255,0.9); backdrop-filter: blur(10px); border-bottom: 1px solid #E2E8F0; padding: 15px 0; }
        .nav-inner { display: flex; justify-content: space-between; align-items: center; }
        .logo { font-size: 20px; font-weight: 800; color: var(--primary); text-decoration: none; }
        .nav-links a { text-decoration: none; color: var(--text-main); font-weight: 500; margin-left: 24px; transition: color 0.3s; }
        .nav-links a:hover { color: var(--primary); }
        .cta-btn { background: var(--primary); color: var(--white); padding: 10px 24px; border-radius: 8px; text-decoration: none; font-weight: 600; transition: transform 0.2s; }
        .cta-btn:hover { transform: translateY(-2px); opacity: 0.9; }

        /* Hero */
        .hero { padding: 100px 0; background: #FFF; position: relative; overflow: hidden; }
        .hero-content { max-width: 700px; }
        h1 { font-size: 3.5rem; line-height: 1.1; color: var(--dark); margin-bottom: 24px; }
        .hero p { font-size: 1.25rem; color: var(--text-gray); margin-bottom: 32px; }

        /* Sections */
        section { padding: var(--spacing) 0; }
        h2 { font-size: 2.5rem; text-align: center; margin-bottom: 48px; color: var(--dark); }
        .grid-3 { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 30px; }
        .card { background: var(--white); padding: 30px; border-radius: var(--radius); border: 1px solid #E2E8F0; transition: box-shadow 0.3s; }
        .card:hover { box-shadow: var(--shadow); }

        /* Footer */
        footer { background: var(--dark); color: #94A3B8; padding: 60px 0; margin-top: var(--spacing); }
        .footer-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 40px; }
        
        /* Responsive */
        @media (max-width: 768px) { h1 { font-size: 2.5rem; } .nav-links { display: none; } .footer-grid { grid-template-columns: 1fr; } }