/* roulang page: index */
:root {
      --primary-deep: #0D7377;
      --accent-orange: #F77F00;
      --bg-warm: #F8F6F2;
      --white: #FFFFFF;
      --text-dark: #1A1A1A;
      --text-body: #3D3D3D;
      --text-muted: #6B6B6B;
      --border-light: #EAEAEA;
      --shadow-sm: 0 4px 20px rgba(0,0,0,0.04);
      --shadow-hover: 0 8px 30px rgba(0,0,0,0.08);
      --radius-lg: 24px;
      --radius-md: 16px;
      --radius-sm: 12px;
      --radius-btn: 30px;
      --transition: 0.25s ease-in-out;
    }

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

    body {
      font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", "Inter", sans-serif;
      background-color: var(--bg-warm);
      color: var(--text-body);
      font-size: 16px;
      line-height: 1.7;
      -webkit-font-smoothing: antialiased;
    }

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

    h1, h2, h3, h4 {
      color: var(--text-dark);
      font-weight: 700;
    }

    h1 {
      font-size: 40px;
      letter-spacing: -0.5px;
      line-height: 1.2;
    }

    h2 {
      font-size: 32px;
      letter-spacing: -0.3px;
      margin-bottom: 1rem;
    }

    h3 {
      font-size: 20px;
      font-weight: 600;
      letter-spacing: 0;
    }

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

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

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      transition: all 0.2s ease;
    }

    /* 导航 */
    #header {
      position: sticky;
      top: 0;
      z-index: 50;
      background: rgba(255, 255, 255, 0.92);
      backdrop-filter: blur(12px);
      height: 72px;
      display: flex;
      align-items: center;
      border-bottom: 1px solid rgba(0,0,0,0.03);
      box-shadow: 0 2px 12px rgba(0,0,0,0.02);
    }

    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }

    .logo {
      font-weight: 700;
      font-size: 1.5rem;
      color: var(--primary-deep);
      display: flex;
      align-items: center;
      gap: 8px;
      letter-spacing: -0.3px;
    }
    .logo i {
      font-size: 1.8rem;
      color: var(--accent-orange);
    }

    .nav-links {
      display: flex;
      align-items: center;
      gap: 2rem;
    }
    .nav-links a {
      font-weight: 500;
      color: var(--text-body);
      position: relative;
      padding: 8px 0;
    }
    .nav-links a:hover {
      color: var(--primary-deep);
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--accent-orange);
      transition: width 0.2s;
    }
    .nav-links a:hover::after {
      width: 100%;
    }

    .btn-primary {
      background: var(--accent-orange);
      color: white;
      border: none;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      letter-spacing: 0.5px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: 0.2s;
      box-shadow: 0 4px 12px rgba(247,127,0,0.25);
      white-space: nowrap;
    }
    .btn-primary:hover {
      background: #E06B00;
      transform: scale(1.03);
      box-shadow: 0 8px 20px rgba(247,127,0,0.35);
    }

    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary-deep);
      color: var(--primary-deep);
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      display: inline-flex;
      align-items: center;
      gap: 6px;
    }
    .btn-outline:hover {
      background: var(--primary-deep);
      color: white;
    }

    .text-cta {
      color: var(--accent-orange);
      font-weight: 600;
      display: inline-flex;
      align-items: center;
      gap: 6px;
    }
    .text-cta i {
      transition: transform 0.2s;
    }
    .text-cta:hover i {
      transform: translateX(4px);
    }

    .hamburger {
      display: none;
      font-size: 1.6rem;
      background: none;
      border: none;
      color: var(--text-dark);
    }

    /* Hero */
    #hero {
      padding: 5rem 0 6rem;
      background: linear-gradient(135deg, rgba(13,115,119,0.03) 0%, rgba(247,127,0,0.03) 100%);
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 5fr 7fr;
      gap: 3rem;
      align-items: center;
    }
    .hero-content h1 {
      margin-bottom: 1.2rem;
    }
    .hero-accent-line {
      width: 60px;
      height: 4px;
      background: var(--accent-orange);
      margin: 1.5rem 0 1.8rem;
    }
    .hero-sub {
      font-size: 1.2rem;
      color: var(--text-muted);
      margin-bottom: 2.2rem;
      max-width: 90%;
    }
    .hero-actions {
      display: flex;
      gap: 1.2rem;
      flex-wrap: wrap;
    }
    .hero-image {
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      border-radius: var(--radius-lg);
      height: 380px;
      box-shadow: var(--shadow-sm);
      position: relative;
      overflow: hidden;
    }
    .hero-image::after {
      content: '';
      position: absolute;
      inset: 0;
      background: linear-gradient(135deg, rgba(13,115,119,0.1) 0%, rgba(0,0,0,0.05) 100%);
    }

    /* 通用板块 */
    section {
      padding: 5rem 0;
    }
    .section-title {
      text-align: center;
      margin-bottom: 3rem;
    }
    .section-title h2 {
      display: inline-block;
      position: relative;
    }

    /* 服务卡片 */
    .card-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .service-card {
      background: var(--white);
      border-radius: var(--radius-md);
      padding: 2rem 1.8rem;
      box-shadow: var(--shadow-sm);
      border: 1px solid var(--border-light);
      transition: var(--transition);
    }
    .service-card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
      border-color: transparent;
    }
    .service-icon {
      font-size: 2.4rem;
      color: var(--primary-deep);
      margin-bottom: 1.5rem;
      transition: transform 0.2s;
    }
    .service-card:hover .service-icon {
      transform: scale(1.1);
      color: var(--accent-orange);
    }

    /* 数据徽章 */
    #stats {
      background: #E8F4F4;
      border-radius: var(--radius-lg);
      margin: 3rem auto;
      max-width: 1100px;
    }
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      text-align: center;
      padding: 2.5rem 2rem;
      gap: 1.5rem;
    }
    .stat-number {
      font-size: 48px;
      font-weight: 800;
      color: var(--primary-deep);
      line-height: 1.1;
    }
    .stat-label {
      font-size: 14px;
      color: var(--text-muted);
      margin-top: 0.4rem;
    }

    /* 解决方案交错 */
    .solution-row {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 2rem;
      margin-bottom: 2rem;
    }
    .solution-card {
      background: white;
      border-radius: var(--radius-md);
      padding: 1.8rem;
      border-left: 4px solid var(--primary-deep);
      box-shadow: var(--shadow-sm);
    }
    .checklist {
      list-style: none;
      margin-top: 1rem;
    }
    .checklist li {
      display: flex;
      align-items: center;
      gap: 10px;
      margin-bottom: 0.8rem;
      color: var(--text-body);
    }
    .checklist i {
      color: var(--accent-orange);
      font-size: 1rem;
    }

    /* 案例 */
    .case-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
    }
    .case-card {
      background: white;
      border-radius: var(--radius-sm);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
    }
    .case-card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-2px);
    }
    .case-img {
      height: 180px;
      background-size: cover;
      background-position: center;
      position: relative;
    }
    .case-img::after {
      content: '\f002';
      font-family: 'Font Awesome 6 Free';
      font-weight: 900;
      position: absolute;
      top: 50%;
      left: 50%;
      transform: translate(-50%, -50%);
      color: white;
      font-size: 2rem;
      opacity: 0;
      transition: 0.2s;
    }
    .case-card:hover .case-img::after {
      opacity: 1;
    }
    .case-info {
      padding: 1rem;
    }
    .case-tag {
      background: #f0f0f0;
      color: var(--text-muted);
      padding: 2px 12px;
      border-radius: 20px;
      font-size: 0.75rem;
      display: inline-block;
      margin-top: 6px;
    }

    /* FAQ */
    .faq-item {
      background: white;
      border-radius: var(--radius-sm);
      margin-bottom: 12px;
      box-shadow: 0 2px 8px rgba(0,0,0,0.02);
      border: 1px solid var(--border-light);
    }
    .faq-question {
      padding: 1.2rem 1.8rem;
      font-weight: 600;
      font-size: 18px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      background: none;
      border: none;
      width: 100%;
      text-align: left;
      color: var(--text-dark);
    }
    .faq-answer {
      padding: 0 1.8rem 1.2rem;
      color: var(--text-body);
      background: #F9F9F9;
      display: none;
    }
    .faq-item.active .faq-answer {
      display: block;
    }
    .faq-icon {
      color: var(--accent-orange);
      font-weight: bold;
      transition: transform 0.3s;
    }
    .faq-item.active .faq-icon {
      transform: rotate(180deg);
    }

    /* CTA */
    .cta-box {
      background: white;
      border-radius: var(--radius-lg);
      padding: 3rem;
      text-align: center;
      box-shadow: var(--shadow-sm);
      max-width: 700px;
      margin: 0 auto;
    }
    .email-input-group {
      display: flex;
      max-width: 480px;
      margin: 1.8rem auto 0;
    }
    .email-input-group input {
      flex:1;
      padding: 14px 20px;
      border: 1px solid #DDD;
      border-radius: 30px 0 0 30px;
      outline: none;
      font-size: 1rem;
    }
    .email-input-group input:focus {
      border-color: var(--primary-deep);
    }
    .email-input-group button {
      border-radius: 0 30px 30px 0;
      padding: 14px 28px;
      background: var(--accent-orange);
      color: white;
      border: none;
      font-weight: 600;
    }

    /* Footer */
    #footer {
      background: #1A1A1A;
      color: #B0B0B0;
      padding: 4rem 0 1.5rem;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 2rem;
    }
    .footer-brand p {
      margin-top: 1rem;
      font-size: 0.95rem;
    }
    .footer-links h4, .footer-contact h4 {
      color: white;
      margin-bottom: 1rem;
    }
    .footer-links a, .footer-contact a {
      display: block;
      margin-bottom: 0.5rem;
      color: #B0B0B0;
    }
    .footer-links a:hover, .footer-contact a:hover {
      color: var(--accent-orange);
    }
    .copyright {
      border-top: 1px solid #333;
      margin-top: 2.5rem;
      padding-top: 1.5rem;
      text-align: center;
      font-size: 0.9rem;
    }

    @media (max-width: 992px) {
      .card-grid { grid-template-columns: repeat(2, 1fr); }
      .case-grid { grid-template-columns: repeat(2, 1fr); }
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: block; }
      .hero-grid { grid-template-columns: 1fr; }
      .hero-image { height: 260px; }
      .card-grid, .case-grid { grid-template-columns: 1fr; }
      .stats-grid { grid-template-columns: repeat(2, 1fr); }
      .solution-row { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }
    @media (max-width: 576px) {
      h1 { font-size: 28px; }
      .container { padding: 0 16px; }
    }