/* roulang page: index */
:root {
      --primary: #E8452D;
      --primary-hover: #C0392B;
      --primary-soft: rgba(232, 69, 45, 0.08);
      --dark: #1C1C1E;
      --ice: #F5F5F7;
      --white: #FFFFFF;
      --gray-light: #EAEAEC;
      --gray-border: #D1D1D6;
      --gray-text: #A1A1A6;
      --text-main: #1C1C1E;
      --text-secondary: #636366;
      --shadow-sm: 0 4px 20px rgba(0,0,0,0.06);
      --shadow-md: 0 8px 30px rgba(0,0,0,0.12);
      --radius-card: 12px;
      --radius-btn: 8px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", system-ui, -apple-system, sans-serif;
      --transition: 0.25s ease;
    }
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    html {
      scroll-behavior: smooth;
      scroll-padding-top: 80px;
    }
    body {
      font-family: var(--font-sans);
      line-height: 1.7;
      color: var(--text-main);
      background-color: var(--ice);
      -webkit-font-smoothing: antialiased;
    }
    img {
      max-width: 100%;
      display: block;
      height: auto;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition);
    }
    button, input, textarea {
      font-family: inherit;
    }
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }
    /* 导航 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: rgba(255,255,255,0.96);
      backdrop-filter: blur(10px);
      -webkit-backdrop-filter: blur(10px);
      border-bottom: 1px solid rgba(0,0,0,0.05);
      z-index: 100;
      transition: box-shadow 0.3s;
    }
    .header.shadow {
      box-shadow: 0 4px 15px rgba(0,0,0,0.04);
    }
    .nav {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 70px;
    }
    .logo {
      font-size: 1.8rem;
      font-weight: 700;
      color: var(--dark);
      letter-spacing: -0.3px;
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .logo i {
      color: var(--primary);
      font-size: 2rem;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
      list-style: none;
    }
    .nav-links a {
      font-size: 0.95rem;
      font-weight: 500;
      color: var(--text-secondary);
      padding: 6px 0;
      border-bottom: 2px solid transparent;
    }
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--primary);
      border-bottom-color: var(--primary);
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 0.95rem;
      border: none;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      gap: 6px;
      transition: background 0.2s, transform 0.2s;
      white-space: nowrap;
    }
    .btn-primary:hover {
      background: var(--primary-hover);
      transform: scale(1.02);
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--primary);
      color: var(--primary);
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 0.95rem;
      cursor: pointer;
      transition: background 0.2s, color 0.2s;
    }
    .btn-outline:hover {
      background: var(--primary-soft);
      color: var(--primary-hover);
    }
    .btn-ghost {
      background: transparent;
      border: 1.5px solid white;
      color: white;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      cursor: pointer;
      transition: background 0.2s;
    }
    .btn-ghost:hover {
      background: rgba(255,255,255,0.15);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: none;
      border: none;
      padding: 8px;
    }
    .hamburger span {
      width: 24px;
      height: 2.5px;
      background: var(--dark);
      border-radius: 2px;
      transition: 0.3s;
    }
    /* 移动端导航 */
    .mobile-menu {
      position: fixed;
      top: 70px;
      left: 0;
      width: 100%;
      background: rgba(255,255,255,0.98);
      backdrop-filter: blur(15px);
      flex-direction: column;
      padding: 24px;
      gap: 20px;
      display: none;
      border-bottom: 1px solid var(--gray-light);
      z-index: 99;
    }
    .mobile-menu.active {
      display: flex;
    }
    .mobile-menu a {
      font-size: 1.1rem;
      font-weight: 500;
    }
    /* Hero */
    .hero {
      background: linear-gradient(135deg, #1C1C1E 0%, #2A2A2D 100%);
      color: white;
      padding: 120px 0 80px;
      margin-top: 70px;
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }
    .hero-content h1 {
      font-size: 3rem;
      font-weight: 700;
      line-height: 1.25;
      margin-bottom: 20px;
    }
    .hero-content p {
      font-size: 1.2rem;
      color: rgba(255,255,255,0.8);
      margin-bottom: 32px;
      max-width: 480px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .hero-image img {
      max-height: 450px;
      margin: 0 auto;
      border-radius: 24px;
      box-shadow: 0 20px 40px rgba(0,0,0,0.5);
    }
    /* 通用区块 */
    section {
      padding: 80px 0;
    }
    .section-title {
      font-size: 2rem;
      font-weight: 650;
      margin-bottom: 16px;
      color: var(--dark);
    }
    .section-sub {
      color: var(--text-secondary);
      margin-bottom: 48px;
      font-size: 1.1rem;
    }
    /* 服务卡片 */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .service-card {
      background: var(--white);
      border-radius: var(--radius-card);
      padding: 32px 24px;
      box-shadow: var(--shadow-sm);
      transition: transform 0.25s, box-shadow 0.25s;
      text-align: left;
    }
    .service-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-md);
    }
    .service-icon {
      width: 56px;
      height: 56px;
      background: var(--primary-soft);
      border-radius: 12px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
      color: var(--primary);
      font-size: 28px;
    }
    .service-card h3 {
      font-size: 1.3rem;
      margin-bottom: 10px;
    }
    .service-card p {
      color: var(--text-secondary);
      font-size: 0.95rem;
    }
    /* 数据深色区块 */
    .stats-section {
      background: var(--dark);
      color: white;
    }
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
      text-align: center;
    }
    .stat-number {
      font-size: 2.8rem;
      font-weight: 700;
      color: var(--primary);
    }
    .stat-label {
      color: rgba(255,255,255,0.7);
      margin-top: 8px;
    }
    /* 案例logo */
    .partners-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
    }
    .partner-item {
      background: var(--white);
      border-radius: var(--radius-card);
      padding: 24px;
      display: flex;
      align-items: center;
      justify-content: center;
      filter: grayscale(1);
      opacity: 0.8;
      transition: 0.3s;
    }
    .partner-item:hover {
      filter: grayscale(0);
      opacity: 1;
    }
    /* 流程 */
    .steps-grid {
      display: flex;
      justify-content: space-between;
      align-items: flex-start;
      gap: 16px;
    }
    .step {
      text-align: center;
      flex: 1;
    }
    .step-circle {
      width: 64px;
      height: 64px;
      background: var(--primary-soft);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 0 auto 16px;
      font-weight: 700;
      font-size: 1.5rem;
      color: var(--primary);
    }
    .step h4 {
      margin-bottom: 8px;
    }
    .step-arrow {
      display: flex;
      align-items: center;
      color: var(--gray-border);
      font-size: 1.5rem;
      margin-top: 20px;
    }
    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      background: var(--white);
      border-radius: var(--radius-card);
      margin-bottom: 12px;
      overflow: hidden;
      box-shadow: var(--shadow-sm);
    }
    .faq-question {
      width: 100%;
      background: transparent;
      border: none;
      padding: 20px 24px;
      font-size: 1.05rem;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      background: #f9f9f9;
      padding: 0 24px;
    }
    .faq-answer p {
      padding: 16px 0;
      color: var(--text-secondary);
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
    }
    /* 联系表单 */
    .contact-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 40px;
    }
    .contact-form input,
    .contact-form textarea {
      width: 100%;
      padding: 14px;
      border: 1px solid var(--gray-border);
      border-radius: var(--radius-btn);
      margin-bottom: 16px;
      transition: 0.2s;
    }
    .contact-form input:focus,
    .contact-form textarea:focus {
      outline: none;
      border-color: var(--primary);
      box-shadow: 0 0 0 3px rgba(232,69,45,0.15);
    }
    .contact-info p {
      margin-bottom: 16px;
      display: flex;
      align-items: center;
      gap: 10px;
    }
    .social-icons i {
      font-size: 1.5rem;
      margin-right: 16px;
      color: var(--text-secondary);
      transition: 0.2s;
    }
    .social-icons i:hover {
      color: var(--primary);
    }
    /* 页脚 */
    .footer {
      background: var(--dark);
      color: var(--gray-text);
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    .footer h4 {
      color: white;
      margin-bottom: 16px;
    }
    .footer a {
      color: var(--gray-text);
      display: block;
      margin-bottom: 8px;
    }
    .footer a:hover {
      color: white;
    }
    .copyright {
      border-top: 1px solid #2c2c2e;
      margin-top: 40px;
      padding-top: 20px;
      text-align: center;
      font-size: 0.9rem;
    }
    @media (max-width: 1024px) {
      .hero-grid {
        grid-template-columns: 1fr;
        text-align: center;
      }
      .hero-content p {
        max-width: 100%;
      }
      .services-grid {
        grid-template-columns: repeat(2, 1fr);
      }
      .stats-grid {
        grid-template-columns: repeat(2, 1fr);
      }
      .partners-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    @media (max-width: 768px) {
      .nav-links {
        display: none;
      }
      .hamburger {
        display: flex;
      }
      .hero-content h1 {
        font-size: 2.2rem;
      }
      .services-grid,
      .stats-grid,
      .partners-grid {
        grid-template-columns: 1fr;
      }
      .steps-grid {
        flex-direction: column;
        align-items: center;
      }
      .step-arrow {
        display: none;
      }
      .contact-grid {
        grid-template-columns: 1fr;
      }
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }