/* roulang page: index */
:root {
      --primary: #0057FF;
      --primary-hover: #0042CC;
      --secondary: #FF4D00;
      --secondary-hover: #E64500;
      --bg: #F8FAFC;
      --card-bg: #FFFFFF;
      --card-border: #E2E8F0;
      --text: #334155;
      --heading: #0F172A;
      --muted: #64748B;
      --success: #10B981;
      --dark-cta-bg: #0F172A;
      --radius-card: 16px;
      --radius-btn: 8px;
      --shadow-card: 0 4px 20px rgba(0, 0, 0, 0.04);
      --shadow-card-hover: 0 12px 32px rgba(0, 0, 0, 0.08);
      --transition: 0.3s ease;
      --container-width: 1200px;
      --font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
    }

    * { box-sizing: border-box; margin: 0; padding: 0; }
    html { scroll-behavior: smooth; }
    body {
      font-family: var(--font-family);
      color: var(--text);
      background-color: var(--bg);
      line-height: 1.5;
      -webkit-font-smoothing: antialiased;
    }
    a { text-decoration: none; color: inherit; }
    img { max-width: 100%; height: auto; display: block; }
    button, input { font-family: inherit; }

    .container {
      max-width: var(--container-width);
      margin: 0 auto;
      padding: 0 20px;
    }

    /* 导航 */
    .navbar {
      position: sticky;
      top: 0;
      z-index: 50;
      background: var(--card-bg);
      border-bottom: 1px solid var(--card-border);
      backdrop-filter: blur(12px);
      background-color: rgba(255,255,255,0.9);
      height: 72px;
      display: flex;
      align-items: center;
    }
    .nav-container {
      width: 100%;
      display: flex;
      align-items: center;
      justify-content: space-between;
      max-width: var(--container-width);
      margin: 0 auto;
      padding: 0 20px;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-size: 24px;
      font-weight: 700;
      color: var(--primary);
      letter-spacing: -0.5px;
    }
    .logo i { font-size: 32px; color: var(--secondary); }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
      list-style: none;
    }
    .nav-links a {
      font-weight: 500;
      color: var(--text);
      transition: color 0.2s;
      font-size: 15px;
    }
    .nav-links a:hover { color: var(--primary); }
    .nav-cta {
      background: var(--secondary);
      color: white;
      padding: 12px 28px;
      border-radius: 50px;
      font-weight: 700;
      transition: background 0.2s, box-shadow 0.2s;
      box-shadow: 0 4px 12px rgba(255,77,0,0.2);
    }
    .nav-cta:hover { background: var(--secondary-hover); box-shadow: 0 6px 16px rgba(255,77,0,0.25); }
    .menu-toggle {
      display: none;
      font-size: 28px;
      background: none;
      border: none;
      color: var(--heading);
      cursor: pointer;
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .menu-toggle { display: block; }
      .nav-container { flex-wrap: wrap; }
      .mobile-menu {
        display: none;
        flex-direction: column;
        width: 100%;
        background: rgba(255,255,255,0.98);
        position: absolute;
        top: 72px;
        left: 0;
        padding: 30px 20px;
        box-shadow: var(--shadow-card);
        gap: 24px;
        backdrop-filter: blur(15px);
        list-style: none;
        border-radius: 0 0 var(--radius-card) var(--radius-card);
      }
      .mobile-menu.open { display: flex; }
      .mobile-menu a { font-weight: 600; color: var(--heading); }
      .mobile-menu .nav-cta { display: inline-block; width: fit-content; }
    }

    /* 区块间距 */
    section { padding: 100px 0; }
    @media (max-width: 768px) { section { padding: 60px 0; } }

    /* 首屏 */
    .hero {
      display: flex;
      align-items: center;
      min-height: 85vh;
      background: linear-gradient(180deg, rgba(248,250,252,0.9) 0%, var(--bg) 100%);
      position: relative;
      overflow: hidden;
    }
    .hero .container {
      display: flex;
      flex-wrap: wrap;
      align-items: center;
      width: 100%;
    }
    .hero-left { flex: 1 1 50%; padding-right: 30px; }
    .hero-right { flex: 1 1 50%; position: relative; }
    .hero-right img {
      max-width: 100%;
      border-radius: 24px;
      box-shadow: 0 24px 48px rgba(0,0,0,0.12);
      transform: perspective(800px) rotateY(-5deg);
    }
    h1 {
      font-size: 48px;
      font-weight: 700;
      line-height: 1.2;
      letter-spacing: -0.5px;
      color: var(--heading);
      margin-bottom: 24px;
    }
    .hero-sub {
      font-size: 18px;
      color: var(--muted);
      margin-bottom: 36px;
      line-height: 1.7;
      max-width: 480px;
    }
    .hero-btns {
      display: flex;
      flex-wrap: wrap;
      gap: 16px;
      margin-bottom: 32px;
    }
    .btn-primary {
      background: var(--secondary);
      color: white;
      padding: 16px 36px;
      border-radius: 50px;
      font-weight: 700;
      box-shadow: 0 8px 20px rgba(255,77,0,0.3);
      transition: transform 0.2s, box-shadow 0.2s, background 0.2s;
      border: none;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      gap: 8px;
    }
    .btn-primary:hover { background: var(--secondary-hover); transform: translateY(-2px); box-shadow: 0 12px 26px rgba(255,77,0,0.35); }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      padding: 16px 36px;
      border-radius: 50px;
      font-weight: 700;
      transition: 0.2s;
    }
    .btn-outline:hover { background: var(--primary); color: white; }
    .trust-tag {
      display: flex;
      align-items: center;
      gap: 16px;
      font-size: 15px;
      color: var(--muted);
      flex-wrap: wrap;
    }
    .trust-tag i { color: var(--success); margin-right: 5px; }
    @media (max-width: 768px) {
      .hero .container { flex-direction: column; }
      .hero-left { padding-right: 0; text-align: center; margin-bottom: 40px; }
      .hero-right { margin-top: 30px; }
      h1 { font-size: 39px; }
    }

    /* 数据网格 */
    .data-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; margin-top: 10px; }
    .data-item {
      background: var(--card-bg);
      padding: 32px 20px;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      transition: var(--transition);
      text-align: center;
      border: 1px solid var(--card-border);
    }
    .data-item:hover { box-shadow: var(--shadow-card-hover); transform: translateY(-5px); }
    .data-number {
      font-size: 42px;
      font-weight: 800;
      color: var(--primary);
      margin-bottom: 8px;
    }
    .data-label { font-weight: 500; color: var(--muted); }
    @media (max-width: 900px) { .data-grid { grid-template-columns: repeat(2,1fr); } }
    @media (max-width: 520px) { .data-grid { grid-template-columns: 1fr; } }

    /* 服务优势交替 */
    .advantage-row {
      display: flex;
      align-items: center;
      gap: 60px;
      margin-bottom: 80px;
    }
    .advantage-row.reverse { flex-direction: row-reverse; }
    .adv-img { flex: 1; }
    .adv-img img {
      border-radius: 24px;
      width: 100%;
      box-shadow: var(--shadow-card);
    }
    .adv-text { flex: 1; }
    .adv-text h2 { font-size: 34px; margin-bottom: 20px; color: var(--heading); }
    .adv-list { list-style: none; margin: 20px 0 0; }
    .adv-list li {
      display: flex;
      align-items: center;
      gap: 12px;
      margin-bottom: 14px;
      font-weight: 500;
    }
    .adv-list i { color: var(--success); font-size: 18px; }
    @media (max-width: 768px) {
      .advantage-row, .advantage-row.reverse { flex-direction: column; gap: 40px; }
    }

    /* 方案对比卡片 */
    .plan-grid {
      display: grid;
      grid-template-columns: repeat(3,1fr);
      gap: 24px;
      margin-top: 32px;
    }
    .plan-card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 36px 24px;
      box-shadow: var(--shadow-card);
      border: 1px solid var(--card-border);
      text-align: center;
      transition: var(--transition);
    }
    .plan-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-card-hover); }
    .plan-card.featured {
      border: 2px solid var(--primary);
      position: relative;
    }
    .badge {
      background: var(--secondary);
      color: white;
      font-size: 13px;
      padding: 6px 17px;
      border-radius: 30px;
      font-weight: 700;
      position: absolute;
      top: -12px;
      left: 50%;
      transform: translateX(-50%);
    }
    .plan-price { font-size: 26px; font-weight: 800; margin: 24px 0 16px; color: var(--heading); }
    .plan-features { list-style: none; text-align: left; margin: 24px 0; }
    .plan-features li { padding: 10px 0; border-bottom: 1px solid var(--card-border); display: flex; gap: 8px; }
    .btn {
      display: inline-block;
      padding: 14px 28px;
      border-radius: 50px;
      font-weight: 700;
      transition: 0.2s;
    }
    .btn-outline-sm { border: 2px solid var(--primary); color: var(--primary); }
    .btn-solid { background: var(--secondary); color: white; }
    @media (max-width: 768px) { .plan-grid { grid-template-columns: 1fr; } }

    /* 案例瀑布流 / 卡片网格 */
    .case-grid {
      display: grid;
      grid-template-columns: repeat(3,1fr);
      gap: 28px;
    }
    .case-card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
    }
    .case-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-card-hover); }
    .case-img { background: #E2E8F0; height: 160px; position: relative; }
    .case-img img { object-fit: cover; width: 100%; height: 100%; }
    .case-body { padding: 24px; }
    .case-tag { background: rgba(0,87,255,0.08); color: var(--primary); padding: 4px 16px; border-radius: 20px; font-weight: 600; font-size: 13px; margin-bottom: 12px; display: inline-block; }
    .case-result { font-weight: 700; color: var(--secondary); margin-top: 16px; }
    @media (max-width: 900px) { .case-grid { grid-template-columns: repeat(2,1fr); } }
    @media (max-width: 520px) { .case-grid { grid-template-columns: 1fr; } }

    /* FAQ 手风琴 */
    .faq-item {
      border-bottom: 1px solid var(--card-border);
      padding: 20px 0;
      cursor: pointer;
    }
    .faq-question {
      font-weight: 700;
      font-size: 18px;
      display: flex;
      align-items: center;
      gap: 12px;
      justify-content: space-between;
      color: var(--heading);
    }
    .faq-answer { padding-top: 14px; color: var(--muted); display: none; }
    .faq-item.active .faq-answer { display: block; }
    .faq-item.active .faq-question { color: var(--secondary); }

    /* dark CTA */
    .dark-cta {
      background: var(--dark-cta-bg);
      color: white;
      text-align: center;
      border-radius: 28px;
      padding: 70px 20px;
      margin: 60px auto;
    }
    .dark-cta h2 { font-size: 36px; color: white; margin-bottom: 20px; }
    .footer-urity { font-size: 14px; opacity: 0.7; }
    footer {
      background: #1E293B;
      color: #CBD5E1;
      padding: 60px 0 30px;
    }
    .Footer-links a:hover { color: white; }

    h2.section-title { font-size: 36px; font-weight: 700; margin-bottom: 16px; text-align: center; color: var(--heading); }
    .bg-soft { margin-top: 20px; }