/* roulang page: index */
:root {
      --primary-green: #1E7A3E;
      --energy-orange: #F15A24;
      --deep-charcoal: #1E1E1E;
      --light-bg: #F7F9FC;
      --warm-yellow: #FFB81C;
      --white: #ffffff;
      --dark-nav: #121212;
      --footer-bg: #1A1A1A;
      --text-light: rgba(255,255,255,0.8);
      --shadow-sm: 0 4px 20px rgba(0,0,0,0.06);
      --shadow-hover: 0 12px 32px rgba(0,0,0,0.12);
      --radius-card: 12px;
      --radius-btn: 30px;
      --transition: 0.3s ease;
      --font-title: 'PingFang SC Bold', 'Noto Sans SC Bold', sans-serif;
      --font-body: 'PingFang SC Regular', 'Noto Sans SC', sans-serif;
      --font-number: 'DIN Alternate', 'Bebas Neue', sans-serif;
    }
    
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    
    body {
      font-family: var(--font-body);
      font-size: 16px;
      line-height: 1.75;
      color: #333;
      background-color: var(--white);
      display: flex;
      min-height: 100vh;
      overflow-x: hidden;
    }
    
    /* 左侧竖向导航 (桌面) */
    .side-nav {
      width: 220px;
      background-color: var(--dark-nav);
      position: fixed;
      top: 0;
      left: 0;
      height: 100vh;
      display: flex;
      flex-direction: column;
      z-index: 30;
      box-shadow: 2px 0 15px rgba(0,0,0,0.2);
      transition: transform 0.3s ease;
    }
    
    .brand-area {
      padding: 28px 20px 32px;
      border-bottom: 1px solid rgba(255,255,255,0.08);
      margin-bottom: 12px;
    }
    
    .logo-link {
      display: flex;
      align-items: center;
      gap: 10px;
      text-decoration: none;
      color: white;
    }
    
    .logo-icon {
      font-size: 32px;
      color: var(--energy-orange);
    }
    
    .logo-text {
      font-family: var(--font-title);
      font-size: 22px;
      letter-spacing: 1px;
      background: linear-gradient(135deg, #fff, #ddd);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }
    
    .nav-stack {
      display: flex;
      flex-direction: column;
      padding: 8px 16px;
      flex: 1;
    }
    
    .nav-item {
      color: rgba(255,255,255,0.75);
      text-decoration: none;
      padding: 12px 16px;
      margin: 4px 0;
      border-radius: 8px;
      font-weight: 500;
      transition: var(--transition);
      display: flex;
      align-items: center;
      gap: 10px;
      font-size: 15px;
      border-left: 3px solid transparent;
    }
    
    .nav-item i {
      width: 20px;
      text-align: center;
      font-size: 16px;
    }
    
    .nav-item:hover {
      color: white;
      background: rgba(255,255,255,0.08);
    }
    
    .nav-item.active {
      color: white;
      background: rgba(241,90,36,0.15);
      border-left: 3px solid var(--energy-orange);
      font-weight: 600;
    }
    
    /* 右侧内容区 */
    .main-content {
      margin-left: 220px;
      width: calc(100% - 220px);
      flex: 1;
      background: var(--white);
    }
    
    /* 移动端顶部导航 */
    .mobile-header {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 56px;
      background: var(--dark-nav);
      z-index: 40;
      align-items: center;
      justify-content: space-between;
      padding: 0 20px;
      box-shadow: 0 2px 10px rgba(0,0,0,0.3);
    }
    
    .mobile-logo {
      display: flex;
      align-items: center;
      gap: 8px;
      color: white;
    }
    
    .hamburger {
      font-size: 24px;
      color: white;
      cursor: pointer;
      background: none;
      border: none;
    }
    
    .mobile-menu {
      display: none;
      position: fixed;
      top: 56px;
      left: 0;
      width: 100%;
      background: var(--dark-nav);
      flex-direction: column;
      padding: 16px;
      z-index: 39;
      box-shadow: 0 8px 20px rgba(0,0,0,0.3);
    }
    
    .mobile-menu a {
      color: rgba(255,255,255,0.8);
      padding: 14px 16px;
      text-decoration: none;
      border-bottom: 1px solid rgba(255,255,255,0.08);
      display: flex;
      align-items: center;
      gap: 10px;
    }
    
    /* 容器与板块 */
    .section {
      padding: 100px 0;
    }
    
    .container-custom {
      max-width: 1100px;
      margin: 0 auto;
      padding: 0 40px;
    }
    
    h2 {
      font-family: var(--font-title);
      font-size: 38px;
      color: var(--deep-charcoal);
      margin-bottom: 16px;
      letter-spacing: -0.5px;
    }
    
    h3.subtitle {
      font-family: var(--font-body);
      font-size: 20px;
      color: #5a6c7d;
      font-weight: 400;
      margin-bottom: 48px;
    }
    
    /* Hero */
    #hero {
      height: 100vh;
      display: flex;
      align-items: center;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      background-blend-mode: overlay;
      background-color: rgba(13,27,14,0.85);
      position: relative;
    }
    
    .hero-content {
      padding-left: 60px;
      max-width: 700px;
    }
    
    .hero-content h1 {
      font-family: var(--font-title);
      font-size: 52px;
      color: white;
      text-shadow: 0 2px 10px rgba(0,0,0,0.6);
      margin-bottom: 20px;
      line-height: 1.2;
    }
    
    .hero-content .hero-sub {
      font-size: 20px;
      color: rgba(255,255,255,0.8);
      margin-bottom: 40px;
      font-weight: 400;
    }
    
    .btn-group {
      display: flex;
      gap: 20px;
      flex-wrap: wrap;
    }
    
    .btn-primary {
      background: var(--energy-orange);
      color: white;
      padding: 14px 36px;
      border-radius: 30px;
      font-weight: 600;
      text-decoration: none;
      display: inline-flex;
      align-items: center;
      gap: 8px;
      transition: var(--transition);
      border: none;
      font-size: 17px;
      box-shadow: 0 8px 18px rgba(241,90,36,0.3);
    }
    
    .btn-primary:hover {
      background: #D9441A;
      transform: scale(1.03);
      color: white;
    }
    
    .btn-outline {
      border: 2px solid white;
      color: white;
      padding: 14px 36px;
      border-radius: 30px;
      font-weight: 600;
      text-decoration: none;
      transition: var(--transition);
      background: transparent;
    }
    
    .btn-outline:hover {
      background: white;
      color: var(--deep-charcoal);
    }
    
    /* 服务卡片 非对称 */
    .services-grid {
      display: flex;
      gap: 24px;
      flex-wrap: wrap;
    }
    
    .card-wide {
      flex: 1 1 55%;
      background: white;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
      padding: 32px;
      transition: var(--transition);
      border-left: 5px solid var(--primary-green);
      display: flex;
      flex-direction: column;
    }
    
    .card-stack {
      flex: 1 1 40%;
      display: flex;
      flex-direction: column;
      gap: 24px;
    }
    
    .card-small {
      background: white;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
      padding: 24px;
      transition: var(--transition);
      border-left: 5px solid var(--energy-orange);
    }
    
    .card-wide:hover, .card-small:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-hover);
    }
    
    .icon-circle {
      font-size: 40px;
      color: var(--primary-green);
      margin-bottom: 16px;
    }
    
    .card-small .icon-circle {
      color: var(--energy-orange);
    }
    
    /* 数据优势 */
    .stats-row {
      display: flex;
      justify-content: space-around;
      flex-wrap: wrap;
      gap: 20px;
    }
    
    .stat-item {
      text-align: center;
    }
    
    .stat-number {
      font-family: var(--font-number);
      font-size: 52px;
      color: var(--energy-orange);
      font-weight: 700;
    }
    
    /* 案例网格 */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(2,1fr);
      gap: 24px;
    }
    
    .case-card {
      position: relative;
      border-radius: var(--radius-card);
      overflow: hidden;
      aspect-ratio: 16/9;
      background: #ddd;
    }
    
    .case-card img {
      width: 100%;
      height: 100%;
      object-fit: cover;
    }
    
    .case-overlay {
      position: absolute;
      bottom: 0;
      left: 0;
      right: 0;
      background: linear-gradient(transparent, rgba(0,0,0,0.7));
      color: white;
      padding: 20px;
      transition: var(--transition);
    }
    
    .case-card:hover .case-overlay {
      background: linear-gradient(transparent, rgba(0,0,0,0.85));
    }
    
    /* 解决方案步骤 */
    .steps-flex {
      display: flex;
      justify-content: space-between;
      align-items: flex-start;
      flex-wrap: wrap;
      position: relative;
    }
    
    .step-item {
      text-align: center;
      flex: 1;
      min-width: 120px;
    }
    
    .step-circle {
      width: 60px;
      height: 60px;
      border-radius: 50%;
      background: white;
      border: 3px solid var(--primary-green);
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 24px;
      font-weight: bold;
      color: var(--primary-green);
      margin: 0 auto 16px;
    }
    
    /* FAQ 手风琴 */
    .accordion-item {
      border-bottom: 1px solid #e0e0e0;
    }
    
    .accordion-title {
      background: none;
      border: none;
      width: 100%;
      text-align: left;
      padding: 20px 0;
      font-size: 18px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      cursor: pointer;
    }
    
    .accordion-content {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: #555;
    }
    
    /* CTA 尾屏 */
    #contact {
      background: linear-gradient(135deg, #F15A24, #D9441A);
      color: white;
      text-align: center;
      padding: 100px 0;
    }
    
    /* 页脚 */
    .footer {
      background: var(--footer-bg);
      color: #aaa;
      padding: 48px 0 24px;
    }
    
    .footer-grid {
      display: flex;
      justify-content: space-between;
      flex-wrap: wrap;
      gap: 30px;
    }
    
    /* 移动端响应式 */
    @media (max-width: 1024px) {
      .side-nav {
        display: none;
      }
      .mobile-header {
        display: flex;
      }
      .main-content {
        margin-left: 0;
        width: 100%;
        padding-top: 56px;
      }
      .hero-content {
        padding-left: 30px;
      }
      .container-custom {
        padding: 0 24px;
      }
    }
    
    @media (max-width: 768px) {
      .services-grid {
        flex-direction: column;
      }
      .cases-grid {
        grid-template-columns: 1fr;
      }
      .stats-row {
        justify-content: center;
      }
      h2 {
        font-size: 32px;
      }
      .hero-content h1 {
        font-size: 38px;
      }
      .section {
        padding: 70px 0;
      }
    }
    
    /* 其他自定义 */
    .text-link {
      color: var(--primary-green);
      font-weight: 500;
      text-decoration: none;
    }
    .bg-light {
      background: var(--light-bg);
    }