/* roulang page: index */
/* ----- 设计变量与基础重置 ----- */
    :root {
      --primary: #F04E23;
      --primary-hover: #D43D1A;
      --secondary: #1A1A1A;
      --accent: #00D4AA;
      --bg-page: #FAFAF8;
      --bg-card: #FFFFFF;
      --bg-card-alt: #F2F2F0;
      --text-main: #3D3D3D;
      --text-heading: #1A1A1A;
      --text-muted: #757575;
      --white: #FFFFFF;
      --border-light: #E0E0E0;
      
      --font-cn: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
      --font-digits: "Inter", "SF Pro Display", system-ui, sans-serif;
      
      --radius-card: 16px;
      --radius-pill: 50px;
      --radius-badge: 12px;
      --shadow-sm: 0 4px 20px rgba(0,0,0,0.04);
      --shadow-md: 0 12px 32px rgba(0,0,0,0.08);
      
      --max-width: 1280px;
      --nav-height: 72px;
      --section-padding: 100px 0;
    }
    
    *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
    
    html { scroll-behavior: smooth; }
    
    body {
      font-family: var(--font-cn);
      background: var(--bg-page);
      color: var(--text-main);
      line-height: 1.6;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    
    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
    }
    
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s ease, background 0.2s ease;
    }
    
    button, .btn {
      cursor: pointer;
      font-family: var(--font-cn);
      transition: all 0.25s ease;
      border: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
    }
    
    h1, h2, h3 {
      font-family: var(--font-cn);
      color: var(--text-heading);
    }
    
    h1 {
      font-size: 42px;
      line-height: 52px;
      font-weight: 700;
    }
    h2 {
      font-size: 32px;
      line-height: 42px;
      font-weight: 600;
    }
    h3 {
      font-size: 20px;
      line-height: 30px;
      font-weight: 600;
    }
    
    p {
      color: var(--text-main);
      font-weight: 400;
    }
    
    .text-accent { color: var(--accent); }
    .text-primary { color: var(--primary); }
    
    /* 导航栏 */
    #nav {
      position: fixed;
      top: 0;
      width: 100%;
      height: var(--nav-height);
      background: rgba(26, 26, 26, 0.92);
      backdrop-filter: blur(12px);
      z-index: 1000;
      transition: background 0.3s;
      display: flex;
      align-items: center;
    }
    #nav.scrolled {
      background: rgba(26, 26, 26, 0.98);
    }
    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
    }
    .logo {
      font-size: 24px;
      font-weight: 700;
      color: var(--white);
      letter-spacing: 1px;
      display: flex;
      align-items: center;
    }
    .logo span {
      color: var(--primary);
      margin-right: 2px;
    }
    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
      list-style: none;
    }
    .nav-links a {
      color: var(--white);
      font-weight: 500;
      font-size: 15px;
      position: relative;
      padding: 4px 0;
      transition: color 0.2s;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--primary);
      transition: width 0.25s;
    }
    .nav-links a:hover, .nav-links a.active {
      color: var(--primary);
    }
    .nav-links a:hover::after, .nav-links a.active::after {
      width: 100%;
    }
    .hamburger {
      display: none;
      background: none;
      border: none;
      color: white;
      font-size: 24px;
      cursor: pointer;
    }
    
    /* 移动端菜单面板 */
    .mobile-panel {
      display: none;
      position: fixed;
      top: var(--nav-height);
      left: 0;
      width: 100%;
      height: calc(100vh - var(--nav-height));
      background: rgba(26,26,26,0.98);
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 40px;
      z-index: 999;
    }
    .mobile-panel a {
      font-size: 22px;
      color: white;
      font-weight: 600;
    }
    
    /* 全局按钮 */
    .btn-primary {
      background: var(--primary);
      color: white;
      border-radius: var(--radius-pill);
      padding: 14px 36px;
      font-weight: 600;
      box-shadow: 0 4px 12px rgba(240,78,35,0.2);
    }
    .btn-primary:hover {
      background: var(--primary-hover);
      box-shadow: 0 8px 20px rgba(240,78,35,0.3);
      transform: translateY(-1px);
    }
    .btn-outline {
      border: 1.5px solid var(--secondary);
      color: var(--secondary);
      background: transparent;
      border-radius: var(--radius-pill);
      padding: 14px 36px;
      font-weight: 600;
    }
    .btn-outline:hover {
      background: var(--secondary);
      color: white;
    }
    .btn-white-outline {
      border: 1.5px solid white;
      color: white;
      background: transparent;
      border-radius: var(--radius-pill);
      padding: 14px 36px;
    }
    .btn-white-outline:hover {
      background: white;
      color: var(--secondary);
    }
    
    /* 区块通用 */
    section {
      padding: var(--section-padding);
    }
    
    /* Hero */
    #hero {
      background: linear-gradient(135deg, #1A1A1A 0%, #F04E23 100%);
      min-height: 100vh;
      display: flex;
      align-items: center;
      position: relative;
      overflow: hidden;
      padding-top: var(--nav-height);
    }
    .hero-grid {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 60px;
    }
    .hero-left {
      flex: 1;
      color: white;
    }
    .hero-left h1 {
      color: white;
      margin-bottom: 20px;
      font-size: 48px;
      line-height: 1.2;
    }
    .hero-left p {
      color: rgba(255,255,255,0.85);
      font-size: 18px;
      margin-bottom: 36px;
      max-width: 500px;
    }
    .hero-cta-group {
      display: flex;
      gap: 20px;
      flex-wrap: wrap;
    }
    .hero-right {
      display: flex;
      flex-wrap: wrap;
      gap: 24px;
    }
    .stat-badge {
      background: rgba(255,255,255,0.1);
      backdrop-filter: blur(8px);
      border-radius: var(--radius-badge);
      padding: 20px 28px;
      text-align: center;
      color: white;
        min-width: 140px;
    }
    .stat-number {
      font-family: var(--font-digits);
      font-size: 42px;
      font-weight: 800;
      color: var(--accent);
      line-height: 1.2;
    }
    
    /* 标题组 */
    .section-title {
      text-align: center;
      margin-bottom: 60px;
    }
    .section-title h2 {
      display: inline-block;
      position: relative;
    }
    
    /* 优势-非对称布局 */
    .advantages-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 24px;
    }
    .adv-large {
      background: var(--secondary);
      color: white;
      border-radius: var(--radius-card);
      padding: 40px;
      background-image: url('/assets/images/backpic/back-2.webp');
      background-size: cover;
      background-position: center;
      position: relative;
    }
    .adv-large h3, .adv-large p { color: white; position: relative; z-index: 2; }
    .adv-small-grid {
      display: flex;
      flex-direction: column;
      gap: 24px;
    }
    .adv-small {
      background: white;
      border-radius: var(--radius-card);
      padding: 28px;
      box-shadow: var(--shadow-sm);
      transition: all 0.25s;
    }
    .adv-small:hover { box-shadow: var(--shadow-md); transform: translateY(-4px); }
    .adv-icon { font-size: 32px; color: var(--primary); margin-bottom: 16px; }
    
    /* 服务卡片网格 */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .service-card {
      background: white;
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
      transition: all 0.25s;
      display: flex;
      flex-direction: column;
    }
    .service-card:hover { box-shadow: var(--shadow-md); transform: translateY(-6px); }
    .service-img { height: 200px; background-size: cover; background-position: center; }
    .service-body { padding: 24px; display: flex; flex-direction: column; flex:1; }
    .service-body h3 { margin-bottom: 8px; }
    .service-link { color: var(--primary); font-weight: 600; margin-top: auto; display: inline-block; }
    
    /* 场景图文 */
    .scenario-row {
      display: flex;
      align-items: center;
      gap: 60px;
      margin-bottom: 80px;
    }
    .scenario-img {
      flex: 1;
      border-radius: var(--radius-card);
      overflow: hidden;
      height: 360px;
      background-size: cover;
    }
    .scenario-content { flex: 1; }
    
    /* 案例滚动 */
    .cases-scroll {
      display: flex;
      gap: 24px;
      overflow-x: auto;
      padding-bottom: 20px;
    }
    .case-card {
      min-width: 280px;
      background: white;
      border-radius: var(--radius-card);
      padding: 24px;
      box-shadow: var(--shadow-sm);
    }
    
    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
    }
    .faq-question {
      width: 100%;
      background: none;
      padding: 20px 0;
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
      font-size: 18px;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-main);
    }
    
    /* CTA 区块 */
    #cta {
      background: var(--secondary);
      text-align: center;
      color: white;
    }
    #cta h2 { color: white; }
    
    /* 页脚 */
    footer {
      background: var(--secondary);
      color: #B0B0B0;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    
    @media (max-width: 768px) {
      h1 { font-size: 32px; line-height: 40px; }
      h2 { font-size: 24px; }
      .hamburger { display: block; }
      .nav-links { display: none; }
      .hero-grid { flex-direction: column; }
      .advantages-grid { grid-template-columns: 1fr; }
      .services-grid { grid-template-columns: 1fr; }
      .scenario-row { flex-direction: column; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }