/* roulang page: index */
:root {
      --primary-blue: #1E3A5F;
      --primary-blue-hover: #14273F;
      --accent-green: #2C5F2D;
      --accent-green-light: #3E7A40;
      --bg-page: #F8FAFC;
      --bg-card: #FFFFFF;
      --text-heading: #0F172A;
      --text-body: #334155;
      --text-muted: #64748B;
      --text-light: #CBD5E1;
      --border-light: #E2E8F0;
      --border-input: #E9EEF4;
      --focus-ring: #2C5F2D;
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 6px;
      --shadow-card: 0 4px 12px rgba(0, 0, 0, 0.04);
      --shadow-card-hover: 0 14px 28px rgba(0, 0, 0, 0.08);
      --shadow-nav: 0 2px 8px rgba(0, 0, 0, 0.03);
      --transition-base: all 0.25s ease;
      --font-stack: -apple-system, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --container-max: 1280px;
      --section-gap: 80px;
    }

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

    body {
      font-family: var(--font-stack);
      background-color: var(--bg-page);
      color: var(--text-body);
      line-height: 1.6;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 32px;
    }

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

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

    button, .btn {
      cursor: pointer;
      border: none;
      background: none;
      font-family: var(--font-stack);
    }

    h1, h2, h3 {
      color: var(--text-heading);
      font-weight: 700;
      line-height: 1.3;
    }

    /* 导航栏 */
    .header {
      position: sticky;
      top: 0;
      z-index: 50;
      background: rgba(255,255,255,0.96);
      backdrop-filter: blur(12px);
      height: 72px;
      border-bottom: 1px solid var(--border-light);
      box-shadow: var(--shadow-nav);
      display: flex;
      align-items: center;
    }

    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 32px;
    }

    .logo {
      font-size: 1.5rem;
      font-weight: 700;
      color: var(--primary-blue);
      display: flex;
      align-items: center;
      gap: 6px;
      white-space: nowrap;
    }
    .logo i {
      color: var(--accent-green);
      font-size: 1.85rem;
    }

    .nav-menu {
      display: flex;
      align-items: center;
      gap: 36px;
      list-style: none;
    }

    .nav-link {
      font-size: 0.95rem;
      font-weight: 500;
      color: var(--text-body);
      padding: 6px 0;
      border-bottom: 2px solid transparent;
      transition: var(--transition-base);
    }

    .nav-link.active, .nav-link:hover {
      color: var(--primary-blue);
      border-bottom-color: var(--primary-blue);
    }

    .btn-primary {
      background: var(--primary-blue);
      color: white;
      padding: 10px 22px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 0.95rem;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: var(--transition-base);
      box-shadow: 0 2px 8px rgba(30,58,95,0.18);
      border: none;
    }

    .btn-primary:hover {
      background: var(--primary-blue-hover);
      box-shadow: 0 6px 16px rgba(30,58,95,0.25);
      transform: translateY(-1px);
    }

    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--primary-blue);
      color: var(--primary-blue);
      padding: 10px 22px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 0.95rem;
      transition: var(--transition-base);
    }
    .btn-outline:hover {
      background: rgba(30,58,95,0.05);
      border-color: var(--primary-blue-hover);
      color: var(--primary-blue-hover);
    }

    .mobile-toggle {
      display: none;
      font-size: 1.8rem;
      color: var(--primary-blue);
      background: none;
      border: none;
    }

    /* 板块通用 */
    section {
      padding: var(--section-gap) 0;
    }

    .section-title {
      text-align: center;
      font-size: 36px;
      font-weight: 700;
      margin-bottom: 16px;
      color: var(--text-heading);
    }
    .section-subtitle {
      text-align: center;
      color: var(--text-muted);
      max-width: 660px;
      margin: 0 auto 56px auto;
      font-size: 1.125rem;
    }

    /* Hero 双栏 */
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 48px;
      flex-wrap: wrap;
    }
    .hero-left {
      flex: 1 1 50%;
    }
    .hero-right {
      flex: 1 1 40%;
    }
    .hero-left h1 {
      font-size: 3rem;
      font-weight: 700;
      margin-bottom: 20px;
      color: var(--text-heading);
      line-height: 1.25;
    }
    .hero-left .hero-desc {
      font-size: 1.2rem;
      color: var(--text-muted);
      margin-bottom: 32px;
      line-height: 1.7;
    }
    .hero-buttons {
      display: flex;
      gap: 18px;
      flex-wrap: wrap;
    }
    .hero-image {
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      background-color: #e9edf2;
      border-radius: 24px;
      height: 380px;
      width: 100%;
      box-shadow: 0 25px 45px -12px rgba(0,0,0,0.25);
      transition: var(--transition-base);
    }

    /* 服务网格 2x3 */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }
    .service-card {
      background: var(--bg-card);
      border-radius: var(--radius-card);
      padding: 32px 24px;
      box-shadow: var(--shadow-card);
      transition: var(--transition-base);
      border: 1px solid var(--border-light);
      text-align: left;
    }
    .service-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-card-hover);
      border-color: transparent;
    }
    .service-icon {
      font-size: 2.4rem;
      color: var(--primary-blue);
      margin-bottom: 20px;
      display: block;
    }
    .service-card h3 {
      font-size: 1.3rem;
      margin-bottom: 12px;
      font-weight: 650;
    }
    .service-card p {
      color: var(--text-muted);
      font-size: 0.975rem;
    }

    /* 案例瀑布流 三列 */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }
    .case-card {
      background: var(--bg-card);
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: var(--transition-base);
      display: flex;
      flex-direction: column;
    }
    .case-card:hover {
      transform: translateY(-5px);
      box-shadow: var(--shadow-card-hover);
    }
    .case-img {
      width: 100%;
      aspect-ratio: 16 / 9;
      object-fit: cover;
      background: #dce3eb;
    }
    .case-content {
      padding: 20px 20px 24px;
    }
    .case-content h3 {
      font-size: 1.25rem;
      margin-bottom: 10px;
    }
    .case-content p {
      color: var(--text-muted);
      font-size: 0.9rem;
    }

    /* FAQ 手风琴 */
    .faq-list {
      max-width: 760px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid var(--border-light);
    }
    .faq-question {
      width: 100%;
      display: flex;
      justify-content: space-between;
      align-items: center;
      background: transparent;
      border: none;
      padding: 20px 8px;
      font-size: 1.15rem;
      font-weight: 600;
      color: var(--text-heading);
      text-align: left;
      cursor: pointer;
      transition: color 0.2s;
    }
    .faq-question:hover {
      color: var(--primary-blue);
    }
    .faq-icon {
      font-size: 1.2rem;
      color: var(--primary-blue);
      transition: transform 0.3s ease;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease, padding 0.25s ease;
      color: var(--text-muted);
      padding: 0 8px;
    }
    .faq-item.active .faq-answer {
      max-height: 300px;
      padding: 8px 8px 24px;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }

    /* 联系CTA */
    .contact-cta {
      background: var(--bg-card);
      border-radius: 20px;
      padding: 48px;
      box-shadow: var(--shadow-card);
      display: flex;
      flex-wrap: wrap;
      gap: 48px;
      align-items: flex-start;
    }
    .contact-text {
      flex: 1;
    }
    .contact-text h2 {
      font-size: 2rem;
      margin-bottom: 16px;
    }
    .contact-form {
      flex: 1;
      display: flex;
      flex-direction: column;
      gap: 18px;
    }
    .form-input {
      width: 100%;
      background: #F1F5F9;
      border: 1px solid transparent;
      border-radius: var(--radius-input);
      padding: 14px 16px;
      font-size: 1rem;
      color: var(--text-body);
      transition: 0.2s;
    }
    .form-input:focus {
      outline: none;
      border-color: var(--focus-ring);
      background: white;
    }
    .btn-full {
      width: 100%;
      padding: 14px;
      font-weight: 650;
    }

    /* 页脚 */
    .footer {
      background: #0F1A2E;
      color: var(--text-light);
      padding: 32px 0;
      margin-top: 40px;
    }
    .footer-content {
      display: flex;
      justify-content: space-between;
      align-items: center;
      flex-wrap: wrap;
      gap: 16px;
    }
    .footer-links span {
      margin-left: 24px;
      opacity: 0.8;
      cursor: default;
    }

    @media (max-width: 1024px) {
      :root {
        --section-gap: 60px;
      }
      .services-grid { grid-template-columns: repeat(2,1fr); }
      .cases-grid { grid-template-columns: repeat(2,1fr); }
      .hero-left h1 { font-size: 2.4rem; }
    }

    @media (max-width: 768px) {
      .nav-menu {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 72px;
        left: 0;
        width: 100%;
        background: white;
        border-bottom: 1px solid var(--border-light);
        box-shadow: 0 12px 20px rgba(0,0,0,0.06);
        padding: 24px;
        gap: 16px;
        align-items: flex-start;
      }
      .nav-menu.active {
        display: flex;
      }
      .mobile-toggle {
        display: block;
      }
      .hero-grid {
        flex-direction: column;
      }
      .hero-left, .hero-right {
        width: 100%;
      }
      .hero-image {
        height: 280px;
      }
      .services-grid, .cases-grid {
        grid-template-columns: 1fr;
      }
      .section-title {
        font-size: 28px;
      }
      .contact-cta {
        flex-direction: column;
        padding: 28px;
      }
    }