/* roulang page: index */
/* ----- 设计变量与全局重置 ----- */
    :root {
      --primary-blue: #0A2540;
      --accent-orange: #FF4F00;
      --gray-bg: #F4F5F7;
      --white: #FFFFFF;
      --text-dark: #333333;
      --text-muted: #666666;
      --border-light: #E0E4E8;
      --shadow-sm: 0 4px 12px rgba(10, 37, 64, 0.06);
      --shadow-md: 0 8px 24px rgba(10, 37, 64, 0.12);
      --radius-card: 8px;
      --radius-btn: 4px;
      --font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --transition: 0.3s ease;
    }

    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }

    html {
      scroll-behavior: smooth;
    }

    body {
      font-family: var(--font-family);
      color: var(--text-dark);
      background-color: var(--white);
      line-height: 1.5;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }

    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition);
    }

    img {
      max-width: 100%;
      height: auto;
      display: block;
    }

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      outline: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      transition: var(--transition);
    }

    h1, h2, h3, h4 {
      font-weight: 600;
      line-height: 1.3;
    }

    /* ----- 按钮系统 ----- */
    .btn-primary {
      background-color: var(--accent-orange);
      color: var(--white);
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 500;
      font-size: 16px;
      letter-spacing: 0.3px;
    }
    .btn-primary:hover {
      background-color: #E64600;
      transform: translateY(-1px);
      box-shadow: 0 6px 16px rgba(255, 79, 0, 0.25);
    }

    .btn-secondary {
      background: transparent;
      color: var(--primary-blue);
      border: 1.5px solid var(--primary-blue);
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 500;
    }
    .btn-secondary:hover {
      background-color: var(--primary-blue);
      color: var(--white);
      border-color: var(--primary-blue);
    }

    /* ----- 导航栏：白底平台导航 ----- */
    .main-header {
      position: sticky;
      top: 0;
      z-index: 100;
      background-color: var(--white);
      border-bottom: 1px solid rgba(10, 37, 64, 0.08);
      box-shadow: 0 2px 8px rgba(0,0,0,0.02);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }
    .logo {
      font-size: 24px;
      font-weight: 700;
      color: var(--primary-blue);
      letter-spacing: -0.5px;
    }
    .logo span {
      color: var(--accent-orange);
      margin-left: 2px;
    }
    .nav-menu {
      display: flex;
      align-items: center;
      gap: 36px;
    }
    .nav-link {
      font-size: 16px;
      font-weight: 500;
      color: var(--text-dark);
      position: relative;
      padding: 4px 0;
    }
    .nav-link:hover, .nav-link.active {
      color: var(--accent-orange);
    }
    .nav-link.active::after {
      content: '';
      position: absolute;
      bottom: -2px;
      left: 0;
      width: 100%;
      height: 2px;
      background-color: var(--accent-orange);
    }
    .hamburger {
      display: none;
      font-size: 28px;
      color: var(--primary-blue);
      background: none;
      border: none;
    }

    /* 板块通用间距 */
    .section {
      padding: 80px 0;
    }
    .section-gray {
      background-color: var(--gray-bg);
    }

    /* ----- Hero 双栏布局 ----- */
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
    }
    .hero-left h1 {
      font-size: 48px;
      font-weight: 700;
      color: var(--primary-blue);
      margin-bottom: 20px;
      line-height: 1.2;
    }
    .hero-left .hero-sub {
      font-size: 18px;
      color: var(--text-muted);
      margin-bottom: 32px;
      max-width: 480px;
    }
    .hero-right {
      position: relative;
      border-radius: 16px;
      overflow: hidden;
      box-shadow: var(--shadow-md);
    }
    .hero-right img {
      width: 100%;
      height: auto;
      object-fit: cover;
    }
    .hero-overlay {
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: linear-gradient(135deg, rgba(10,37,64,0.35) 0%, rgba(255,79,0,0.15) 100%);
    }

    /* 亮点网格 2x3 */
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 32px;
    }
    .stat-item {
      background: var(--white);
      padding: 32px 24px;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
      text-align: center;
      transition: var(--transition);
    }
    .stat-item:hover {
      transform: translateY(-5px);
      box-shadow: var(--shadow-md);
    }
    .stat-number {
      font-size: 42px;
      font-weight: 700;
      color: var(--accent-orange);
      line-height: 1.1;
    }
    .stat-divider {
      width: 40px;
      height: 3px;
      background: var(--border-light);
      margin: 12px auto;
    }
    .stat-title {
      font-weight: 600;
      font-size: 18px;
      color: var(--primary-blue);
      margin-bottom: 8px;
    }
    .stat-desc {
      color: var(--text-muted);
      font-size: 14px;
    }

    /* 案例瀑布流卡片 */
    .service-card {
      display: flex;
      background: var(--white);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
      margin-bottom: 40px;
      overflow: hidden;
      transition: var(--transition);
    }
    .service-card:hover {
      box-shadow: var(--shadow-md);
      transform: translateY(-4px);
    }
    .service-img {
      width: 45%;
      object-fit: cover;
    }
    .service-content {
      width: 55%;
      padding: 40px;
      display: flex;
      flex-direction: column;
      justify-content: center;
    }
    .service-content h3 {
      font-size: 24px;
      color: var(--primary-blue);
      margin-bottom: 16px;
    }
    .service-desc {
      color: var(--text-muted);
      margin-bottom: 20px;
      line-height: 1.6;
    }
    .check-list {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 12px;
    }
    .check-list li {
      display: flex;
      align-items: center;
      gap: 12px;
      color: var(--text-dark);
      font-weight: 500;
    }
    .check-list i {
      color: var(--accent-orange);
      font-size: 18px;
    }

    /* 方案对比卡片 */
    .compare-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 32px;
      margin-top: 20px;
    }
    .plan-card {
      background: var(--white);
      border-radius: var(--radius-card);
      padding: 36px 28px;
      box-shadow: var(--shadow-sm);
      display: flex;
      flex-direction: column;
      transition: var(--transition);
      position: relative;
      border: 1px solid var(--border-light);
    }
    .plan-card.featured {
      background: var(--primary-blue);
      color: var(--white);
      border-color: var(--primary-blue);
      transform: scale(1.02);
    }
    .plan-card.featured .plan-name,
    .plan-card.featured .plan-price,
    .plan-card.featured li {
      color: var(--white);
    }
    .plan-badge {
      position: absolute;
      top: 16px;
      right: 16px;
      background: var(--accent-orange);
      color: white;
      padding: 4px 14px;
      border-radius: 20px;
      font-size: 13px;
      font-weight: 600;
    }
    .plan-name {
      font-size: 22px;
      font-weight: 600;
      color: var(--primary-blue);
      margin-bottom: 16px;
    }
    .plan-price {
      font-size: 36px;
      font-weight: 700;
      color: var(--accent-orange);
      margin-bottom: 24px;
    }
    .plan-features {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 14px;
      margin-bottom: 32px;
      flex: 1;
    }
    .plan-features li i {
      color: var(--accent-orange);
      margin-right: 8px;
    }

    /* 信任背书 Logo 墙 */
    .logo-wall {
      display: flex;
      flex-wrap: wrap;
      justify-content: center;
      align-items: center;
      gap: 48px;
      margin-top: 24px;
    }
    .logo-item {
      font-weight: 600;
      font-size: 20px;
      color: var(--text-muted);
      opacity: 0.7;
      transition: var(--transition);
    }

    /* FAQ 手风琴 */
    .faq-grid {
      display: grid;
      grid-template-columns: 1fr 1.5fr;
      gap: 48px;
    }
    .faq-left h2 {
      font-size: 36px;
      color: var(--primary-blue);
      margin-bottom: 12px;
    }
    .accordion-item {
      border-bottom: 1px solid var(--border-light);
      padding: 18px 0;
    }
    .accordion-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
      font-size: 18px;
      color: var(--primary-blue);
      cursor: pointer;
      background: none;
      border: none;
      width: 100%;
      text-align: left;
    }
    .accordion-question i {
      transition: transform 0.3s;
      color: var(--accent-orange);
    }
    .accordion-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: var(--text-muted);
      padding-right: 20px;
    }
    .accordion-item.active .accordion-answer {
      max-height: 200px;
      margin-top: 12px;
    }
    .accordion-item.active .accordion-question i {
      transform: rotate(45deg);
    }

    /* 全局 CTA */
    .cta-band {
      background-color: var(--primary-blue);
      padding: 80px 0;
      text-align: center;
    }
    .cta-band h2 {
      color: var(--white);
      font-size: 40px;
      margin-bottom: 20px;
    }
    .cta-band p {
      color: rgba(255,255,255,0.7);
      font-size: 18px;
      margin-bottom: 32px;
    }

    /* 页脚 */
    .footer {
      background: var(--primary-blue);
      color: var(--white);
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1.5fr;
      gap: 40px;
    }
    .footer-col h4 {
      color: var(--accent-orange);
      margin-bottom: 20px;
      font-size: 18px;
    }
    .footer-col ul {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 12px;
    }
    .footer-col a {
      color: rgba(255,255,255,0.8);
    }
    .copyright {
      margin-top: 40px;
      padding-top: 20px;
      border-top: 1px solid rgba(255,255,255,0.1);
      text-align: center;
      color: rgba(255,255,255,0.5);
      font-size: 14px;
    }

    /* 移动端响应式 */
    @media (max-width: 1024px) {
      .hero-grid { gap: 32px; }
      .stats-grid { grid-template-columns: repeat(2, 1fr); }
    }
    @media (max-width: 768px) {
      .nav-menu { display: none; }
      .hamburger { display: block; }
      .hero-grid { grid-template-columns: 1fr; }
      .hero-left h1 { font-size: 36px; }
      .service-card { flex-direction: column; }
      .service-img, .service-content { width: 100%; }
      .compare-grid { grid-template-columns: 1fr; }
      .faq-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
      .stats-grid { grid-template-columns: 1fr; }
      .container { padding: 0 20px; }
    }