/* roulang page: index */
/* 自定义CSS变量覆盖与完整设计系统 */
    :root {
      --primary: #D32F2F;
      --primary-dark: #B71C1C;
      --secondary: #1E1E1E;
      --accent: #F57C00;
      --bg: #FAFAFA;
      --card-bg: #FFFFFF;
      --border: #E0E0E0;
      --text: #1E1E1E;
      --text-light: #555555;
      --text-muted: #777777;
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 6px;
      --shadow-sm: 0 2px 12px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 24px rgba(0,0,0,0.08);
      --font-sans: 'Inter', 'PingFang SC', 'Microsoft YaHei', 'Hiragino Sans GB', system-ui, -apple-system, sans-serif;
    }
    
    * {
      box-sizing: border-box;
    }
    
    body {
      margin: 0;
      font-family: var(--font-sans);
      background-color: var(--bg);
      color: var(--text);
      line-height: 1.7;
      -webkit-font-smoothing: antialiased;
    }
    
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s ease;
    }
    
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }
    
    @media (max-width: 768px) {
      .container {
        padding: 0 20px;
      }
    }
    
    /* 导航栏 */
    .navbar {
      position: sticky;
      top: 0;
      z-index: 50;
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(12px);
      height: 64px;
      border-bottom: 1px solid var(--border);
      display: flex;
      align-items: center;
    }
    
    .nav-inner {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }
    
    .logo {
      font-weight: 700;
      font-size: 1.6rem;
      letter-spacing: -0.5px;
      color: var(--secondary);
    }
    .logo span {
      color: var(--primary);
    }
    
    .nav-links {
      display: flex;
      gap: 2rem;
      align-items: center;
      font-weight: 500;
      color: var(--secondary);
    }
    
    .nav-links a {
      position: relative;
      padding: 4px 0;
    }
    
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--primary);
      transition: width 0.2s ease;
    }
    
    .nav-links a:hover {
      color: var(--primary);
    }
    
    .nav-links a:hover::after,
    .nav-links a.active::after {
      width: 100%;
    }
    
    .btn-primary {
      background: var(--primary);
      color: white;
      font-weight: 600;
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      transition: all 0.25s ease;
      display: inline-block;
      text-align: center;
      border: none;
      cursor: pointer;
      box-shadow: 0 4px 10px rgba(211,47,47,0.2);
      white-space: nowrap;
    }
    
    .btn-primary:hover {
      background: var(--primary-dark);
      transform: translateY(-2px);
      box-shadow: 0 12px 20px rgba(183,28,28,0.25);
    }
    
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      font-weight: 600;
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      transition: all 0.25s ease;
      display: inline-block;
      text-align: center;
      cursor: pointer;
    }
    
    .btn-outline:hover {
      background: rgba(211,47,47,0.08);
      transform: translateY(-2px);
    }
    
    /* 汉堡菜单 */
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: none;
      border: none;
      padding: 8px;
    }
    .hamburger span {
      width: 24px;
      height: 2.5px;
      background: var(--secondary);
      border-radius: 2px;
      transition: 0.3s;
    }
    .mobile-menu {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100vh;
      background: rgba(30,30,30,0.96);
      backdrop-filter: blur(12px);
      display: flex;
      flex-direction: column;
      justify-content: center;
      align-items: center;
      gap: 2.2rem;
      z-index: 100;
      transform: translateX(100%);
      transition: transform 0.35s ease;
    }
    .mobile-menu.open {
      transform: translateX(0);
    }
    .mobile-menu a {
      color: white;
      font-size: 1.8rem;
      font-weight: 600;
    }
    .close-menu {
      position: absolute;
      top: 24px;
      right: 28px;
      font-size: 2.2rem;
      color: white;
      background: none;
      border: none;
      cursor: pointer;
    }
    
    @media (max-width: 768px) {
      .nav-links {
        display: none;
      }
      .hamburger {
        display: flex;
      }
      .navbar {
        height: 56px;
      }
    }
    
    /* Hero 斜切动态分割 */
    .hero-section {
      min-height: 90vh;
      display: flex;
      align-items: center;
      background: linear-gradient(135deg, #fafafa 0%, #f5f5f5 100%);
      position: relative;
      overflow: hidden;
    }
    
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 3rem;
      align-items: center;
    }
    
    .hero-text h1 {
      font-size: clamp(2rem, 5vw, 3.5rem);
      font-weight: 700;
      line-height: 1.2;
      color: var(--secondary);
      margin-bottom: 1.2rem;
    }
    .hero-text h1 .highlight {
      color: var(--primary);
    }
    .hero-sub {
      font-size: 1.4rem;
      font-weight: 500;
      color: var(--text-light);
      margin-bottom: 1.5rem;
    }
    .hero-desc {
      color: #555;
      margin-bottom: 2rem;
      max-width: 90%;
    }
    
    .hero-image {
      position: relative;
      border-radius: 24px;
      overflow: hidden;
      box-shadow: var(--shadow-md);
      transform: skewY(-2deg);
      background: #ddd;
    }
    .hero-image img {
      width: 100%;
      height: auto;
      object-fit: cover;
      aspect-ratio: 4/3;
    }
    
    @media (max-width: 768px) {
      .hero-grid {
        grid-template-columns: 1fr;
        text-align: center;
      }
      .hero-image {
        transform: none;
        margin-top: 1.5rem;
        order: -1;
      }
      .hero-desc {
        max-width: 100%;
      }
      .hero-section {
        min-height: 70vh;
        padding: 3rem 0;
      }
    }
    
    /* 板块通用 */
    .section {
      padding: 5rem 0;
    }
    .section-title {
      font-size: 2.2rem;
      font-weight: 700;
      margin-bottom: 1rem;
      color: var(--secondary);
    }
    .section-sub {
      color: var(--text-muted);
      margin-bottom: 3rem;
    }
    
    /* 解决方案卡片 - 左侧竖线+不对称 */
    .solutions-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }
    .solution-card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 28px 24px;
      box-shadow: var(--shadow-sm);
      position: relative;
      overflow: hidden;
      transition: all 0.3s ease;
      border-left: 5px solid var(--primary);
      display: flex;
      flex-direction: column;
      gap: 16px;
    }
    .solution-card:nth-child(2) {
      transform: translateY(12px);
    }
    .solution-card:hover {
      box-shadow: var(--shadow-md);
      transform: translateY(-4px);
    }
    .solution-card .icon {
      font-size: 2.2rem;
      color: var(--primary);
      width: 44px;
      height: 44px;
      display: flex;
      align-items: center;
    }
    .solution-card h3 {
      font-size: 1.5rem;
      font-weight: 650;
    }
    @media (max-width: 768px) {
      .solutions-grid {
        grid-template-columns: 1fr;
      }
      .solution-card:nth-child(2) {
        transform: none;
      }
    }
    
    /* 数据优势区 */
    .advantages-bg {
      background: #f4f4f4;
    }
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 2rem;
      text-align: center;
    }
    .stat-item {
      display: flex;
      flex-direction: column;
      align-items: center;
    }
    .stat-number {
      font-size: 3.2rem;
      font-weight: 700;
      color: var(--primary);
      line-height: 1.1;
      font-family: 'Inter', sans-serif;
    }
    .stat-label {
      color: var(--text-light);
      margin-top: 0.8rem;
      font-weight: 500;
    }
    @media (max-width: 768px) {
      .stats-grid {
        grid-template-columns: 1fr 1fr;
      }
    }
    
    /* 案例横向滚动 */
    .cases-scroll {
      display: flex;
      gap: 24px;
      overflow-x: auto;
      padding-bottom: 16px;
      scroll-snap-type: x mandatory;
    }
    .case-card {
      min-width: 300px;
      max-width: 320px;
      background: white;
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
      transition: 0.3s;
      scroll-snap-align: start;
      position: relative;
    }
    .case-img {
      height: 180px;
      overflow: hidden;
      position: relative;
    }
    .case-img img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      transition: transform 0.4s;
    }
    .case-card:hover .case-img img {
      transform: scale(1.05);
    }
    .case-tag {
      position: absolute;
      top: 12px;
      left: 12px;
      background: rgba(0,0,0,0.65);
      color: white;
      padding: 4px 12px;
      border-radius: 20px;
      font-size: 0.8rem;
      font-weight: 600;
    }
    .case-body {
      padding: 18px;
    }
    
    /* FAQ */
    .faq-container {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid var(--border);
      padding: 18px 0;
    }
    .faq-question {
      font-weight: 600;
      font-size: 1.15rem;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      color: var(--secondary);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, padding 0.3s;
      background: #f9f9f9;
      border-left: 4px solid var(--primary);
      margin-top: 12px;
      padding-left: 16px;
      color: #444;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding: 12px 16px;
    }
    
    /* CTA 区域 */
    .cta-band {
      background: linear-gradient(135deg, #1E1E1E 0%, #2a2a2a 100%);
      position: relative;
      overflow: hidden;
    }
    .cta-form input, .cta-form textarea {
      background: rgba(255,255,255,0.1);
      border: none;
      border-bottom: 2px solid rgba(255,255,255,0.4);
      padding: 12px 8px;
      color: white;
      width: 100%;
      border-radius: 4px;
      transition: 0.2s;
    }
    .cta-form input:focus, .cta-form textarea:focus {
      outline: none;
      border-bottom-color: var(--primary);
      background: rgba(255,255,255,0.18);
    }
    
    /* 页脚 */
    .footer {
      background: #1A1A1A;
      color: #CCC;
      padding: 3rem 0 1.5rem;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1.5fr 1.2fr;
      gap: 2rem;
    }
    .footer a:hover {
      color: var(--primary);
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
    }