/* roulang page: index */
:root {
      --primary: #E0432A;
      --primary-dark: #C0391F;
      --secondary: #1A1D23;
      --accent: #FFB81C;
      --bg-light: #F9F9F6;
      --bg-white: #FFFFFF;
      --text-main: #1A1D23;
      --text-muted: #5A5D63;
      --text-light: #E0E0E0;
      --border-light: #E5E5E5;
      --border-dark: rgba(255,255,255,0.1);
      --radius-lg: 12px;
      --radius-md: 8px;
      --radius-sm: 6px;
      --shadow-sm: 0 2px 12px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 30px rgba(0,0,0,0.08);
      --font-sans: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
      --font-number: "Inter", "Roboto", sans-serif;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--bg-light);
      color: var(--text-main);
      line-height: 1.5;
      -webkit-font-smoothing: antialiased;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    button, input {
      font-family: inherit;
    }
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 32px;
    }
    @media (max-width: 768px) {
      .container {
        padding: 0 20px;
      }
    }

    /* 导航 */
    #header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      transition: background 0.3s ease, box-shadow 0.3s ease;
      background: transparent;
      padding: 16px 0;
    }
    #header.scrolled {
      background: #FFFFFF;
      box-shadow: 0 2px 20px rgba(0,0,0,0.06);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 32px;
    }
    .logo {
      font-weight: 700;
      font-size: 24px;
      letter-spacing: -0.3px;
      color: var(--secondary);
      display: flex;
      align-items: center;
    }
    .logo span {
      color: var(--primary);
      margin-right: 4px;
    }
    .nav-links {
      display: flex;
      gap: 36px;
      align-items: center;
      list-style: none;
    }
    .nav-links a {
      font-weight: 500;
      font-size: 16px;
      color: var(--text-main);
      transition: color 0.2s;
      position: relative;
    }
    .nav-links a:hover {
      color: var(--primary);
    }
    .nav-cta {
      background: var(--primary);
      color: white;
      border: none;
      padding: 12px 28px;
      border-radius: var(--radius-md);
      font-weight: 600;
      font-size: 15px;
      cursor: pointer;
      transition: background 0.2s, transform 0.2s;
      white-space: nowrap;
    }
    .nav-cta:hover {
      background: var(--primary-dark);
      transform: scale(1.03);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: none;
      border: none;
      cursor: pointer;
      padding: 8px;
    }
    .hamburger span {
      width: 25px;
      height: 2px;
      background: var(--secondary);
      transition: 0.3s;
      display: block;
    }
    @media (max-width: 768px) {
      .nav-links {
        display: none;
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100vh;
        background: rgba(255,255,255,0.98);
        flex-direction: column;
        justify-content: center;
        align-items: center;
        gap: 32px;
        z-index: 999;
      }
      .nav-links.active {
        display: flex;
      }
      .hamburger {
        display: flex;
        z-index: 1001;
      }
      .nav-cta.desktop-only {
        display: none;
      }
    }
    @media (min-width: 769px) {
      .mobile-cta {
        display: none;
      }
    }
    .mobile-cta {
      margin-top: 24px;
    }

    /* Hero */
    #hero {
      padding: 140px 0 100px;
      background: var(--bg-light);
      position: relative;
      overflow: hidden;
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 60px;
    }
    .hero-left {
      flex: 1;
    }
    .hero-right {
      flex: 1;
      position: relative;
      clip-path: polygon(8% 0, 100% 0, 92% 100%, 0% 100%);
    }
    .hero-right img {
      width: 100%;
      height: 520px;
      object-fit: cover;
      border-radius: 12px;
    }
    .hero-right::after {
      content: '';
      position: absolute;
      inset: 0;
      background: linear-gradient(135deg, rgba(224,67,42,0.35) 0%, rgba(26,29,35,0.1) 100%);
      border-radius: 12px;
    }
    h1 {
      font-size: 48px;
      line-height: 60px;
      font-weight: 800;
      letter-spacing: -0.5px;
      color: var(--secondary);
      margin-bottom: 24px;
    }
    .hero-sub {
      font-size: 18px;
      color: var(--text-muted);
      line-height: 28px;
      margin-bottom: 40px;
      max-width: 480px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      border: none;
      padding: 14px 32px;
      border-radius: var(--radius-md);
      font-weight: 600;
      font-size: 16px;
      cursor: pointer;
      transition: background 0.2s, transform 0.2s;
      display: inline-block;
      text-align: center;
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      transform: scale(1.03);
    }
    .btn-secondary {
      background: transparent;
      border: 2px solid var(--secondary);
      color: var(--secondary);
      padding: 12px 30px;
      border-radius: var(--radius-md);
      font-weight: 600;
      font-size: 16px;
      cursor: pointer;
      transition: 0.2s;
      display: inline-block;
    }
    .btn-secondary:hover {
      background: var(--secondary);
      color: white;
    }
    @media (max-width: 1024px) {
      .hero-grid {
        flex-direction: column;
        gap: 48px;
      }
      .hero-right {
        clip-path: none;
        width: 100%;
      }
      h1 {
        font-size: 40px;
        line-height: 50px;
      }
    }
    @media (max-width: 768px) {
      h1 {
        font-size: 32px;
        line-height: 42px;
      }
      .hero-sub {
        font-size: 16px;
      }
      #hero {
        padding: 120px 0 60px;
      }
    }

    /* 通用板块 */
    section {
      padding: 100px 0;
    }
    @media (max-width: 768px) {
      section {
        padding: 60px 0;
      }
    }
    .section-title {
      font-size: 36px;
      line-height: 48px;
      font-weight: 700;
      margin-bottom: 16px;
      color: var(--secondary);
    }
    .section-sub {
      font-size: 18px;
      color: var(--text-muted);
      margin-bottom: 48px;
      max-width: 700px;
    }

    /* 核心优势 */
    .advantages-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 40px 64px;
    }
    .adv-item {
      display: flex;
      flex-direction: column;
      transition: transform 0.2s;
    }
    .adv-item:hover {
      transform: translateY(-4px);
    }
    .adv-icon {
      width: 48px;
      height: 48px;
      margin-bottom: 16px;
      color: var(--primary);
    }
    .adv-underline {
      width: 32px;
      height: 4px;
      background: var(--accent);
      margin-bottom: 20px;
      transition: width 0.3s;
    }
    .adv-item:hover .adv-underline {
      width: 48px;
    }
    .adv-title {
      font-size: 22px;
      font-weight: 600;
      margin-bottom: 8px;
    }
    .adv-desc {
      color: var(--text-muted);
      font-size: 15px;
      line-height: 24px;
    }
    @media (max-width: 768px) {
      .advantages-grid {
        grid-template-columns: 1fr;
        gap: 32px;
      }
    }

    /* 数据实力 */
    #stats {
      background: var(--secondary);
      color: white;
    }
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 40px;
      text-align: center;
    }
    .stat-number {
      font-family: var(--font-number);
      font-size: 56px;
      font-weight: 800;
      color: var(--accent);
      line-height: 1.2;
    }
    .stat-label {
      font-size: 14px;
      font-weight: 500;
      color: var(--text-light);
      margin-top: 8px;
    }
    @media (max-width: 768px) {
      .stats-grid {
        grid-template-columns: 1fr 1fr;
      }
      .stat-number {
        font-size: 40px;
      }
    }

    /* 服务/产品 非对称网格 */
    .services-layout {
      display: flex;
      gap: 24px;
      flex-wrap: wrap;
    }
    .service-large {
      flex: 2;
      min-width: 300px;
      background: var(--bg-white);
      border-radius: var(--radius-lg);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
      transition: all 0.3s;
      position: relative;
    }
    .service-large img {
      width: 100%;
      height: 320px;
      object-fit: cover;
    }
    .service-large .card-content {
      position: absolute;
      bottom: 0;
      left: 0;
      right: 0;
      padding: 40px;
      background: linear-gradient(transparent, rgba(0,0,0,0.7));
      color: white;
    }
    .service-small-group {
      flex: 1;
      display: flex;
      flex-direction: column;
      gap: 24px;
      min-width: 260px;
    }
    .service-small {
      background: white;
      border-radius: var(--radius-lg);
      padding: 32px;
      box-shadow: var(--shadow-sm);
      transition: all 0.3s;
      border: 1px solid transparent;
    }
    .service-small:hover {
      border-color: var(--primary);
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }
    .service-small img {
      width: 100%;
      height: 140px;
      object-fit: cover;
      border-radius: 8px;
      margin-bottom: 20px;
    }
    .service-small h3 {
      font-size: 20px;
      margin-bottom: 8px;
    }
    .text-link {
      color: var(--primary);
      font-weight: 600;
      display: inline-flex;
      align-items: center;
      gap: 4px;
      margin-top: 12px;
    }
    @media (max-width: 1024px) {
      .services-layout {
        flex-direction: column;
      }
    }

    /* 案例横向滚动 */
    .cases-scroll {
      display: flex;
      gap: 24px;
      overflow-x: auto;
      padding-bottom: 16px;
      scrollbar-width: none;
      -ms-overflow-style: none;
    }
    .cases-scroll::-webkit-scrollbar {
      display: none;
    }
    .case-card {
      min-width: 280px;
      border-radius: var(--radius-lg);
      background: white;
      box-shadow: var(--shadow-sm);
      overflow: hidden;
      flex-shrink: 0;
    }
    .case-card img {
      height: 180px;
      object-fit: cover;
    }
    .case-info {
      padding: 16px;
    }

    /* 流程 */
    .process-steps {
      display: flex;
      justify-content: space-between;
      position: relative;
    }
    .step {
      text-align: center;
      flex: 1;
      position: relative;
    }
    .step-circle {
      width: 48px;
      height: 48px;
      background: var(--primary);
      color: white;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      margin: 0 auto 12px;
      transition: 0.2s;
    }
    .step:hover .step-circle {
      transform: scale(1.1);
      box-shadow: 0 0 0 6px rgba(255,184,28,0.3);
    }
    @media (max-width: 768px) {
      .process-steps {
        flex-direction: column;
        gap: 28px;
      }
    }

    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 24px 0;
    }
    .faq-question {
      font-size: 22px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      cursor: pointer;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: var(--text-muted);
      margin-top: 8px;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
    }

    /* CTA */
    #cta {
      background: var(--secondary);
      color: white;
      text-align: center;
    }
    .cta-buttons {
      display: flex;
      gap: 20px;
      justify-content: center;
      flex-wrap: wrap;
      margin-top: 32px;
    }
    .btn-light {
      border: 2px solid white;
      color: white;
      background: transparent;
      padding: 12px 32px;
      border-radius: var(--radius-md);
      font-weight: 600;
    }
    .btn-light:hover {
      background: white;
      color: var(--secondary);
    }

    /* Footer */
    #footer {
      background: #14161A;
      color: var(--text-light);
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1.5fr;
      gap: 40px;
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
    }
    .copyright {
      text-align: center;
      margin-top: 40px;
      color: #5A5D63;
    }