/* roulang page: index */
:root {
      --primary: #E94E1F;
      --primary-dark: #C63D14;
      --secondary: #1A1A2E;
      --accent: #00B4D8;
      --bg: #F8F9FA;
      --text: #2D2D2D;
      --text-light: #6C757D;
      --white: #FFFFFF;
      --border: #E9ECEF;
      --card-shadow: 0 2px 12px rgba(0,0,0,0.04);
      --card-hover-shadow: 0 8px 24px rgba(0,0,0,0.08);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 6px;
      --transition: 0.2s ease;
      --header-height: 72px;
      --container-max: 1200px;
      --gap-section: 100px;
      --gap-mobile: 60px;
      --font-title: 'Noto Sans SC', sans-serif;
      --font-body: 'Noto Sans SC', sans-serif;
    }

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

    body {
      font-family: var(--font-body);
      background-color: var(--bg);
      color: var(--text);
      line-height: 1.8;
      font-weight: 400;
      -webkit-font-smoothing: antialiased;
    }

    h1, h2, h3, h4 {
      font-family: var(--font-title);
      font-weight: 700;
      line-height: 1.2;
      margin-bottom: 0.5em;
    }

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

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

    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }

    /* 导航 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--header-height);
      background: var(--white);
      z-index: 1000;
      box-shadow: 0 1px 0 var(--border);
      transition: box-shadow var(--transition);
    }

    .header.scrolled {
      box-shadow: 0 2px 12px rgba(0,0,0,0.06);
    }

    .nav {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 100%;
    }

    .logo {
      font-size: 1.8rem;
      font-weight: 800;
      color: var(--primary);
      letter-spacing: -0.5px;
    }
    .logo a { color: inherit; }

    .nav-menu {
      display: flex;
      gap: 2rem;
      list-style: none;
    }
    .nav-menu a {
      font-size: 0.95rem;
      font-weight: 500;
      color: var(--text);
      padding: 0.25rem 0;
      position: relative;
      white-space: nowrap;
    }
    .nav-menu a::after {
      content: '';
      position: absolute;
      left: 0;
      bottom: 0;
      width: 0;
      height: 3px;
      background: var(--primary);
      transition: width var(--transition);
    }
    .nav-menu a:hover { color: var(--primary); }
    .nav-menu a:hover::after { width: 100%; }

    .nav-cta {
      background: linear-gradient(135deg, var(--primary) 0%, #FF6B35 100%);
      color: white;
      padding: 0.6rem 1.5rem;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 0.9rem;
      white-space: nowrap;
      transition: transform var(--transition), box-shadow var(--transition);
    }
    .nav-cta:hover { transform: scale(1.02); box-shadow: 0 4px 12px rgba(233,78,31,0.3); }

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

    /* 移动端导航覆盖 */
    @media (max-width: 768px) {
      .nav-menu {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100vh;
        background: rgba(26,26,46,0.96);
        flex-direction: column;
        justify-content: center;
        align-items: center;
        gap: 2.5rem;
        transform: translateX(100%);
        transition: transform 0.3s ease;
      }
      .nav-menu.active { transform: translateX(0); }
      .nav-menu a {
        color: white;
        font-size: 1.6rem;
        font-weight: 600;
      }
      .nav-cta { display: none; }
      .hamburger { display: flex; z-index: 1001; position: relative; }
    }

    /* Hero */
    .hero {
      min-height: 100vh;
      display: flex;
      align-items: center;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      position: relative;
      margin-top: 0;
      padding-top: var(--header-height);
    }
    .hero::before {
      content: '';
      position: absolute;
      inset: 0;
      background: linear-gradient(135deg, rgba(26,26,46,0.8) 0%, rgba(233,78,31,0.6) 100%);
    }
    .hero-content {
      position: relative;
      z-index: 2;
      color: white;
      max-width: 700px;
    }
    .hero h1 {
      font-size: 3.5rem;
      font-weight: 800;
      margin-bottom: 1rem;
    }
    .hero p {
      font-size: 1.2rem;
      opacity: 0.9;
      margin-bottom: 2rem;
    }
    .hero-buttons {
      display: flex;
      gap: 1rem;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: linear-gradient(135deg, var(--primary) 0%, #FF6B35 100%);
      color: white;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 700;
      border: none;
      cursor: pointer;
      transition: transform var(--transition), box-shadow var(--transition);
    }
    .btn-secondary {
      background: transparent;
      border: 2px solid white;
      color: white;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 700;
      cursor: pointer;
      transition: background var(--transition), color var(--transition);
    }
    .btn-primary:hover { transform: scale(1.03); box-shadow: 0 6px 18px rgba(233,78,31,0.5); }
    .btn-secondary:hover { background: white; color: var(--secondary); }

    @media (max-width: 768px) {
      .hero h1 { font-size: 2.2rem; }
      .hero p { font-size: 1rem; }
    }

    /* 通用区块 */
    section {
      padding: var(--gap-section) 0;
    }
    @media (max-width: 768px) {
      section { padding: var(--gap-mobile) 0; }
    }
    .section-title {
      text-align: center;
      margin-bottom: 48px;
    }
    .section-title h2 {
      font-size: 2.2rem;
      color: var(--secondary);
    }
    .section-title p {
      color: var(--text-light);
      max-width: 600px;
      margin: 0 auto;
    }

    /* 核心优势 非对称栅格 */
    .advantages-grid {
      display: grid;
      grid-template-columns: 5fr 3fr 4fr;
      gap: 24px;
    }
    .adv-card {
      background: var(--white);
      padding: 32px;
      border-radius: var(--radius-card);
      box-shadow: var(--card-shadow);
      transition: var(--transition);
    }
    .adv-card:hover {
      box-shadow: var(--card-hover-shadow);
      transform: translateY(-4px);
    }
    .adv-icon {
      width: 56px;
      height: 56px;
      background: rgba(0,180,216,0.1);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      color: var(--accent);
      font-size: 1.8rem;
      margin-bottom: 1.5rem;
      transition: transform var(--transition);
    }
    .adv-card:hover .adv-icon { transform: scale(1.1); }
    .adv-card h3 { font-size: 1.4rem; margin-bottom: 0.8rem; }
    @media (max-width: 768px) {
      .advantages-grid { grid-template-columns: 1fr; }
    }

    /* 数据服务图文 */
    .service-row {
      display: flex;
      align-items: center;
      gap: 60px;
      margin-bottom: 80px;
    }
    .service-row.reverse { flex-direction: row-reverse; }
    .service-text { flex: 1; }
    .service-img { flex: 1; }
    .service-img img {
      border-radius: var(--radius-card);
      box-shadow: var(--card-shadow);
      width: 100%;
    }
    .metric {
      font-size: 2.8rem;
      font-weight: 800;
      color: var(--accent);
      margin: 1rem 0 0.5rem;
    }
    @media (max-width: 768px) {
      .service-row, .service-row.reverse { flex-direction: column; }
    }

    /* 解决方案卡片 */
    .solutions-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .sol-card {
      background: white;
      padding: 28px;
      border-radius: var(--radius-card);
      box-shadow: var(--card-shadow);
      transition: var(--transition);
      height: fit-content;
    }
    .sol-card:hover { box-shadow: var(--card-hover-shadow); }
    .tag {
      background: rgba(233,78,31,0.1);
      color: var(--primary);
      padding: 4px 12px;
      border-radius: 20px;
      font-size: 0.8rem;
      display: inline-block;
      margin-bottom: 1rem;
    }
    @media (max-width: 768px) {
      .solutions-grid { grid-template-columns: 1fr; }
    }

    /* 案例Logo墙 */
    .logos {
      display: flex;
      flex-wrap: wrap;
      gap: 40px;
      justify-content: center;
      align-items: center;
      filter: grayscale(1);
      opacity: 0.7;
      transition: var(--transition);
      margin-bottom: 2rem;
    }
    .logos img { height: 36px; object-fit: contain; }
    .logos:hover { filter: none; opacity: 1; }

    /* FAQ */
    .faq-item {
      background: white;
      border-radius: var(--radius-card);
      margin-bottom: 16px;
      box-shadow: var(--card-shadow);
      overflow: hidden;
    }
    .faq-question {
      padding: 20px 28px;
      font-weight: 600;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
      border-left: 4px solid transparent;
      transition: var(--transition);
    }
    .faq-item.active .faq-question {
      border-left-color: var(--primary);
      background: #fafafa;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      background: #F8F9FA;
      padding: 0 28px;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding: 20px 28px;
    }

    /* CTA横幅 */
    .cta-banner {
      background: var(--secondary);
      padding: 80px 0;
      text-align: center;
      color: white;
    }
    .cta-form {
      display: flex;
      gap: 12px;
      max-width: 480px;
      margin: 2rem auto 0;
    }
    .cta-form input {
      flex: 1;
      padding: 14px 18px;
      border-radius: var(--radius-input);
      border: none;
      background: white;
    }
    @media (max-width: 520px) {
      .cta-form { flex-direction: column; }
    }

    /* 页脚 */
    .footer {
      background: var(--secondary);
      color: #ccc;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 30px;
    }
    .footer h4 { color: white; margin-bottom: 1.2rem; }
    .footer a { color: #aaa; display: block; margin-bottom: 0.5rem; }
    .footer a:hover { color: var(--primary); }
    .social-icons i {
      font-size: 1.4rem;
      margin-right: 16px;
      color: #aaa;
      transition: var(--transition);
    }
    .social-icons i:hover { color: var(--primary); }
    .copyright {
      text-align: center;
      margin-top: 40px;
      font-size: 0.9rem;
      color: #777;
    }
    @media (max-width: 768px) {
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }