/* roulang page: index */
:root {
      --primary-deep: #0B2B1F;
      --accent-amber: #F4A300;
      --bg-warm: #FAFAF7;
      --text-main: #1A1A1A;
      --text-secondary: #5C5C5C;
      --border-light: #E5E5E0;
      --card-bg: #FFFFFF;
      --card-shadow: 0 4px 20px rgba(0,0,0,0.04);
      --card-shadow-hover: 0 8px 30px rgba(0,0,0,0.08);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 6px;
      --transition-smooth: 0.25s ease;
    }

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

    body {
      font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      background-color: var(--bg-warm);
      color: var(--text-main);
      line-height: 1.5;
      scroll-behavior: smooth;
    }

    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 20px;
    }

    /* 导航样式 */
    .nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: rgba(255,255,255,0.95);
      backdrop-filter: blur(8px);
      box-shadow: 0 2px 10px rgba(0,0,0,0.02);
      z-index: 1000;
      transition: box-shadow 0.3s;
    }
    .nav.scrolled {
      box-shadow: 0 4px 16px rgba(0,0,0,0.05);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 70px;
    }
    .logo {
      font-size: 24px;
      font-weight: 700;
      color: var(--primary-deep);
      letter-spacing: 0.5px;
      text-decoration: none;
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .logo-icon {
      width: 32px;
      height: 32px;
      background: var(--accent-amber);
      border-radius: 6px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: #0B2B1F;
      font-weight: 700;
    }
    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
    }
    .nav-links a {
      text-decoration: none;
      color: var(--text-main);
      font-weight: 500;
      font-size: 16px;
      position: relative;
      padding: 4px 0;
      transition: color 0.2s;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--accent-amber);
      transition: width 0.25s;
    }
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--primary-deep);
    }
    .nav-links a:hover::after,
    .nav-links a.active::after {
      width: 100%;
    }
    .btn-primary {
      background: var(--accent-amber);
      color: var(--primary-deep);
      border: none;
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      cursor: pointer;
      transition: background var(--transition-smooth), transform 0.2s;
      display: inline-block;
      text-decoration: none;
      letter-spacing: 0.3px;
    }
    .btn-primary:hover {
      background: #D98C00;
      transform: translateY(-1px);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary-deep);
      color: var(--primary-deep);
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      cursor: pointer;
      transition: all var(--transition-smooth);
      text-decoration: none;
      display: inline-block;
    }
    .btn-outline:hover {
      background: var(--primary-deep);
      color: white;
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: none;
      border: none;
    }
    .hamburger span {
      width: 25px;
      height: 3px;
      background: var(--primary-deep);
      border-radius: 2px;
      transition: 0.3s;
    }

    /* 区块间距 */
    section {
      padding: 100px 0;
    }

    /* Hero */
    .hero {
      margin-top: 70px;
      display: flex;
      align-items: center;
      gap: 60px;
      min-height: 85vh;
    }
    .hero-content {
      flex: 1 1 50%;
    }
    .hero-title {
      font-size: 48px;
      line-height: 1.25;
      font-weight: 700;
      color: var(--primary-deep);
      margin-bottom: 20px;
      letter-spacing: -0.5px;
    }
    .hero-sub {
      font-size: 18px;
      color: var(--text-secondary);
      margin-bottom: 32px;
      max-width: 480px;
      line-height: 1.6;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .hero-image {
      flex: 1 1 50%;
      border-radius: 24px;
      overflow: hidden;
      box-shadow: 0 20px 40px rgba(0,0,0,0.08);
      background: #f0f0ed;
    }
    .hero-image img {
      width: 100%;
      height: auto;
      display: block;
      object-fit: cover;
      aspect-ratio: 4/3;
    }

    /* 标题 */
    .section-title {
      font-size: 36px;
      font-weight: 600;
      color: var(--primary-deep);
      margin-bottom: 16px;
      text-align: center;
    }
    .section-desc {
      font-size: 17px;
      color: var(--text-secondary);
      max-width: 600px;
      margin: 0 auto 48px;
      text-align: center;
    }

    /* 服务卡片 */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .service-card {
      background: var(--card-bg);
      padding: 32px;
      border-radius: var(--radius-card);
      box-shadow: var(--card-shadow);
      text-align: center;
      transition: transform 0.3s, box-shadow 0.3s;
    }
    .service-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--card-shadow-hover);
    }
    .service-icon {
      width: 48px;
      height: 48px;
      margin: 0 auto 20px;
      color: var(--accent-amber);
      display: flex;
      align-items: center;
      justify-content: center;
    }
    .service-card h3 {
      font-size: 24px;
      font-weight: 600;
      margin-bottom: 12px;
    }
    .service-card p {
      color: var(--text-secondary);
      font-size: 15px;
      line-height: 1.6;
    }

    /* 数据优势 */
    .advantages-bg {
      background: linear-gradient(180deg, #F0F5F3 0%, #FAFAF7 20%);
      border-radius: 40px 40px 0 0;
    }
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
      text-align: center;
    }
    .stat-item {
      padding: 20px 0;
    }
    .stat-number {
      font-size: 56px;
      font-weight: 700;
      color: var(--accent-amber);
      line-height: 1.2;
    }
    .stat-label {
      font-size: 17px;
      color: var(--text-secondary);
      font-weight: 500;
    }

    /* 解决方案流程 */
    .step-row {
      display: flex;
      align-items: center;
      gap: 60px;
      margin-bottom: 80px;
      position: relative;
    }
    .step-row.reverse {
      flex-direction: row-reverse;
    }
    .step-text {
      flex: 1;
      position: relative;
      z-index: 2;
    }
    .step-number {
      font-size: 120px;
      font-weight: 700;
      color: rgba(11,43,31,0.08);
      position: absolute;
      top: -40px;
      left: -30px;
      z-index: -1;
      line-height: 1;
    }
    .step-text h3 {
      font-size: 28px;
      font-weight: 600;
      margin-bottom: 8px;
    }
    .step-text p {
      color: var(--text-secondary);
      line-height: 1.6;
    }
    .step-image {
      flex: 1;
      border-radius: 16px;
      overflow: hidden;
      box-shadow: 0 10px 25px rgba(0,0,0,0.06);
    }
    .step-image img {
      width: 100%;
      height: auto;
      display: block;
      object-fit: cover;
      aspect-ratio: 4/3;
    }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 18px 0;
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      font-weight: 600;
      font-size: 19px;
      color: var(--text-main);
    }
    .faq-icon {
      font-size: 22px;
      color: var(--accent-amber);
      transition: transform 0.3s;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      background: #F7F7F5;
      border-radius: 8px;
      margin-top: 8px;
    }
    .faq-answer p {
      padding: 16px;
      color: var(--text-secondary);
      line-height: 1.6;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }

    /* CTA */
    .cta-section {
      background: var(--primary-deep);
      color: white;
      border-radius: 24px;
      padding: 64px 40px;
      text-align: center;
    }
    .cta-title {
      font-size: 36px;
      font-weight: 600;
      margin-bottom: 12px;
      color: white;
    }
    .cta-sub {
      opacity: 0.8;
      margin-bottom: 32px;
    }
    .contact-form {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
      justify-content: center;
      margin-top: 24px;
    }
    .contact-form input, .contact-form textarea {
      background: white;
      border: none;
      padding: 12px 16px;
      border-radius: var(--radius-input);
      font-size: 15px;
      color: var(--text-main);
      flex: 1 1 200px;
      outline: none;
      border: 2px solid transparent;
      transition: border 0.2s;
    }
    .contact-form input:focus, .contact-form textarea:focus {
      border-color: var(--accent-amber);
    }
    .footer {
      background: var(--primary-deep);
      color: white;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 32px;
    }
    .footer a {
      color: rgba(255,255,255,0.8);
      text-decoration: none;
      font-size: 15px;
    }
    .footer-bottom {
      border-top: 1px solid rgba(255,255,255,0.15);
      margin-top: 40px;
      padding-top: 20px;
      text-align: center;
      font-size: 14px;
      opacity: 0.7;
    }

    @media (max-width: 1024px) {
      .services-grid { grid-template-columns: repeat(2, 1fr); }
      .stats-grid { grid-template-columns: repeat(2, 1fr); }
      .hero { flex-direction: column; }
    }

    @media (max-width: 768px) {
      .hamburger { display: flex; }
      .nav-links {
        position: fixed;
        left: 0; top: 70px;
        width: 100%;
        background: white;
        flex-direction: column;
        padding: 20px;
        gap: 16px;
        display: none;
        box-shadow: 0 20px 25px rgba(0,0,0,0.05);
      }
      .nav-links.open { display: flex; }
      .services-grid, .stats-grid { grid-template-columns: 1fr; }
      .step-row, .step-row.reverse { flex-direction: column; }
      .hero { padding-top: 20px; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
      .hero-title { font-size: 36px; }
    }