/* roulang page: index */
:root {
      --primary: #1A56DB;
      --primary-dark: #1647B8;
      --accent: #F5490B;
      --accent-dark: #D93E08;
      --success: #10B981;
      --warning: #EF4444;
      --bg: #F8FAFC;
      --card-bg: #FFFFFF;
      --text-main: #0F172A;
      --text-secondary: #64748B;
      --border: #E2E8F0;
      --shadow-sm: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
      --shadow-hover: 0 12px 28px rgba(0,0,0,0.12), 0 4px 12px rgba(0,0,0,0.06);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-tag: 6px;
      --transition: all 0.25s ease;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
      --font-mono: "DIN Alternate", "Roboto Mono", "Courier New", monospace;
      --container-max: 1200px;
    }
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: var(--font-sans);
      background-color: var(--bg);
      color: var(--text-main);
      line-height: 1.75;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    a { text-decoration: none; color: inherit; transition: var(--transition); }
    img { max-width: 100%; height: auto; display: block; }
    .container { max-width: var(--container-max); margin: 0 auto; padding: 0 20px; width: 100%; }
    h1, h2, h3 { font-weight: 700; line-height: 1.3; }
    h1 { font-size: 40px; }
    h2 { font-size: 32px; margin-bottom: 16px; }
    h3 { font-size: 20px; font-weight: 600; line-height: 1.4; }
    .section-padding { padding: 100px 0; }
    @media (max-width: 768px) {
      h1 { font-size: 28px; }
      h2 { font-size: 24px; }
      h3 { font-size: 18px; }
      .section-padding { padding: 60px 0; }
    }
    button, .btn {
      font-family: var(--font-sans);
      font-weight: 600;
      font-size: 16px;
      border: none;
      cursor: pointer;
      border-radius: var(--radius-btn);
      transition: var(--transition);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 14px 32px;
      box-shadow: 0 4px 10px rgba(26,86,219,0.2);
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      box-shadow: 0 0 0 3px rgba(26,86,219,0.3);
      transform: translateY(-2px);
    }
    .btn-cta {
      background: var(--accent);
      color: white;
      padding: 16px 40px;
      font-size: 16px;
    }
    .btn-cta:hover {
      background: var(--accent-dark);
      transform: scale(1.03);
      box-shadow: 0 8px 20px rgba(245,73,11,0.35);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      padding: 12px 30px;
    }
    .btn-outline:hover {
      background: #EBF2FE;
      border-color: var(--primary-dark);
    }
    .nav {
      position: fixed; top: 0; left: 0; width: 100%; height: 64px;
      background: rgba(255,255,255,0.9); backdrop-filter: blur(8px);
      z-index: 1000; display: flex; align-items: center;
      transition: background 0.3s, box-shadow 0.3s;
      border-bottom: 1px solid transparent;
    }
    .nav.scrolled {
      background: #FFFFFF;
      box-shadow: 0 2px 12px rgba(0,0,0,0.05);
      border-bottom: 1px solid var(--border);
    }
    .nav-container {
      display: flex; justify-content: space-between; align-items: center;
      width: 100%; max-width: var(--container-max); margin: 0 auto; padding: 0 20px;
    }
    .logo {
      font-size: 22px; font-weight: 700; color: var(--primary);
      display: flex; align-items: center; gap: 6px;
    }
    .logo span { color: var(--text-main); }
    .nav-menu { display: flex; align-items: center; gap: 28px; list-style: none; }
    .nav-menu a {
      font-weight: 500; color: var(--text-secondary); position: relative;
      padding: 8px 0; font-size: 15px;
    }
    .nav-menu a:hover, .nav-menu a.active { color: var(--primary); }
    .nav-menu a.active::after {
      content: ''; position: absolute; bottom: -4px; left: 0; width: 100%;
      height: 3px; background: var(--primary); border-radius: 3px;
    }
    .hamburger { display: none; flex-direction: column; gap: 5px; cursor: pointer; }
    .hamburger span { width: 24px; height: 3px; background: var(--text-main); border-radius: 2px; transition: 0.3s; }
    @media (max-width: 768px) {
      .nav-menu {
        position: fixed; top: 64px; left: 0; width: 100%; background: white;
        flex-direction: column; align-items: flex-start; padding: 24px;
        box-shadow: 0 10px 20px rgba(0,0,0,0.05); transform: translateY(-150%);
        transition: transform 0.3s ease; gap: 20px; z-index: 999;
      }
      .nav-menu.open { transform: translateY(0); }
      .hamburger { display: flex; }
      .nav-cta-desktop { display: none; }
    }
    .hero {
      background: linear-gradient(135deg, #0B1E3D 0%, #1A3A5C 100%);
      min-height: 100vh; display: flex; align-items: center;
      position: relative; overflow: hidden; color: white;
    }
    .hero-grid {
      display: grid; grid-template-columns: 1fr 1fr; gap: 40px; align-items: center;
    }
    .hero-text h1 { color: white; margin-bottom: 20px; }
    .hero-text p { font-size: 18px; color: rgba(255,255,255,0.8); margin-bottom: 32px; }
    .hero-buttons { display: flex; gap: 16px; flex-wrap: wrap; }
    .hero-visual {
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      border-radius: 20px; height: 360px; box-shadow: 0 20px 40px rgba(0,0,0,0.4);
      position: relative;
    }
    .float-data {
      position: absolute; background: rgba(255,255,255,0.1); backdrop-filter: blur(6px);
      padding: 12px 18px; border-radius: 12px; font-family: var(--font-mono);
      font-size: 22px; font-weight: 700; color: var(--accent);
    }
    @media (max-width: 992px) {
      .hero-grid { grid-template-columns: 1fr; text-align: center; }
      .hero-visual { height: 280px; margin-top: 30px; }
      .hero-buttons { justify-content: center; }
    }
    .card {
      background: var(--card-bg); border-radius: var(--radius-card);
      border: 1px solid var(--border); padding: 24px;
      box-shadow: var(--shadow-sm); transition: var(--transition);
    }
    .card:hover {
      box-shadow: var(--shadow-hover); transform: translateY(-4px);
    }
    .grid-3 { display: grid; grid-template-columns: repeat(3,1fr); gap: 24px; }
    .grid-2 { display: grid; grid-template-columns: repeat(2,1fr); gap: 24px; }
    @media (max-width: 992px) { .grid-3, .grid-2 { grid-template-columns: repeat(2,1fr); } }
    @media (max-width: 640px) { .grid-3, .grid-2 { grid-template-columns: 1fr; } }
    .service-grid { display: grid; grid-template-columns: repeat(3,1fr); gap: 24px; margin-top: 40px; }
    @media (max-width: 992px) { .service-grid { grid-template-columns: repeat(2,1fr); } }
    @media (max-width: 640px) { .service-grid { grid-template-columns: 1fr; } }
    .comparison-table {
      display: grid; grid-template-columns: 1fr auto 1fr; gap: 24px; align-items: center;
    }
    .comparison-col { background: white; padding: 32px; border-radius: 16px; }
    .vs-badge {
      background: var(--primary); color: white; width: 48px; height: 48px;
      border-radius: 50%; display: flex; align-items: center; justify-content: center;
      font-weight: 700;
    }
    @media (max-width: 768px) {
      .comparison-table { grid-template-columns: 1fr; }
      .vs-badge { margin: 20px auto; }
    }
    .faq-item {
      border-bottom: 1px solid var(--border); padding: 20px 0;
    }
    .faq-question {
      display: flex; justify-content: space-between; align-items: center;
      cursor: pointer; font-weight: 600;
    }
    .faq-answer { max-height: 0; overflow: hidden; transition: max-height 0.3s ease; color: var(--text-secondary); }
    .faq-item.active .faq-answer { max-height: 200px; margin-top: 12px; }
    .footer {
      background: #0F172A; color: #CBD5E1; padding: 60px 0 30px;
    }
    .footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 40px; }
    @media (max-width: 768px) { .footer-grid { grid-template-columns: 1fr 1fr; } }
    @media (max-width: 480px) { .footer-grid { grid-template-columns: 1fr; } }
    .progress-bar {
      height: 6px; background: #E2E8F0; border-radius: 10px; overflow: hidden;
    }
    .progress-fill { height: 100%; background: var(--primary); width: 0%; border-radius: 10px; }
    .tag {
      background: #F1F5F9; color: var(--text-secondary); padding: 4px 10px;
      border-radius: 20px; font-size: 13px; font-weight: 500;
    }