/* roulang page: index */
:root {
      --primary-dark: #0B1E33;
      --accent-red: #E85D3F;
      --bg-light: #FAFAFA;
      --white: #FFFFFF;
      --text-dark: #1A1A1A;
      --text-gray: #5C5C5C;
      --border-light: #E6E6E6;
      --shadow-sm: 0 2px 8px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 24px rgba(0,0,0,0.06);
      --radius-card: 8px;
      --radius-btn: 4px;
      --font-heading: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      --font-body: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      --font-mono: 'SF Mono', 'Menlo', 'DIN Alternate', 'PingFang SC', monospace;
      --transition: 0.25s ease;
    }
    
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    
    body {
      font-family: var(--font-body);
      background-color: var(--bg-light);
      color: var(--text-dark);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }
    
    h1, h2, h3, h4 {
      font-family: var(--font-heading);
      font-weight: 600;
    }
    
    a {
      color: var(--text-dark);
      text-decoration: none;
      transition: color var(--transition);
    }
    
    a:hover {
      color: var(--accent-red);
    }
    
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    
    /* 容器与布局 */
    .section-container {
      max-width: 1200px;
      margin: 0 auto;
      padding-left: 24px;
      padding-right: 24px;
    }
    
    .spacer-section {
      padding: 80px 0;
    }
    
    @media (max-width: 640px) {
      .spacer-section {
        padding: 48px 0;
      }
    }
    
    /* 导航 */
    .top-bar-custom {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: rgba(255,255,255,0.97);
      backdrop-filter: blur(10px);
      box-shadow: var(--shadow-sm);
      z-index: 100;
      padding: 0 20px;
      height: 70px;
      display: flex;
      align-items: center;
      transition: background 0.3s;
    }
    
    .nav-wrapper {
      max-width: 1200px;
      margin: 0 auto;
      width: 100%;
      display: flex;
      align-items: center;
      justify-content: space-between;
      position: relative;
    }
    
    .logo-brand {
      font-family: var(--font-heading);
      font-weight: 700;
      font-size: 1.5rem;
      color: var(--primary-dark);
      letter-spacing: -0.5px;
      white-space: nowrap;
    }
    
    .logo-brand:hover {
      color: var(--primary-dark);
    }
    
    .nav-links {
      display: flex;
      list-style: none;
      gap: 2rem;
      margin: 0;
    }
    
    .nav-links a {
      color: var(--text-gray);
      font-weight: 500;
      font-size: 0.95rem;
      padding: 0.25rem 0;
      position: relative;
    }
    
    .nav-links a::after {
      content: '';
      position: absolute;
      width: 0;
      height: 2px;
      bottom: 0;
      left: 0;
      background-color: var(--accent-red);
      transition: width var(--transition);
    }
    
    .nav-links a:hover::after {
      width: 100%;
    }
    
    .mobile-menu-trigger {
      display: none;
      background: none;
      border: none;
      font-size: 1.8rem;
      color: var(--primary-dark);
      cursor: pointer;
    }
    
    @media (max-width: 840px) {
      .nav-links {
        display: none;
      }
      .mobile-menu-trigger {
        display: block;
      }
    }
    
    .mobile-menu-panel {
      display: none;
      position: absolute;
      top: 70px;
      left: 0;
      width: 100%;
      background: white;
      box-shadow: var(--shadow-md);
      padding: 1rem 0;
      flex-direction: column;
    }
    
    .mobile-menu-panel.active {
      display: flex;
    }
    
    .mobile-menu-panel a {
      padding: 0.8rem 24px;
      border-bottom: 1px solid var(--border-light);
      color: var(--text-dark);
    }
    
    /* Hero */
    #hero {
      padding-top: 120px;
      background: var(--white);
    }
    
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 3rem;
    }
    
    .hero-left {
      flex: 1 1 55%;
    }
    
    .hero-right {
      flex: 1 1 45%;
      animation: fadeInUp 0.8s ease;
    }
    
    .hero-right img {
      border-radius: 16px;
      box-shadow: 0 20px 35px rgba(0,0,0,0.05);
    }
    
    @keyframes fadeInUp {
      0% { opacity: 0; transform: translateY(25px); }
      100% { opacity: 1; transform: translateY(0); }
    }
    
    .hero-title {
      font-size: clamp(2.5rem, 6vw, 4rem);
      font-weight: 700;
      color: var(--primary-dark);
      line-height: 1.2;
      margin-bottom: 1.5rem;
    }
    
    .hero-sub {
      font-size: 1.25rem;
      color: var(--text-gray);
      margin-bottom: 2.5rem;
      max-width: 500px;
    }
    
    .btn-group {
      display: flex;
      gap: 1rem;
      flex-wrap: wrap;
    }
    
    .btn-primary {
      background: var(--accent-red);
      color: white;
      font-weight: 600;
      padding: 0.85rem 2.2rem;
      border-radius: var(--radius-btn);
      border: none;
      transition: all var(--transition);
      display: inline-block;
      box-shadow: 0 4px 12px rgba(232,93,63,0.3);
    }
    
    .btn-primary:hover {
      background: #D14A2C;
      color: white;
      box-shadow: 0 0 0 3px rgba(232,93,63,0.2);
    }
    
    .btn-outline {
      background: transparent;
      color: var(--primary-dark);
      border: 1px solid var(--primary-dark);
      padding: 0.85rem 2.2rem;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: all var(--transition);
    }
    
    .btn-outline:hover {
      background: rgba(11,30,51,0.05);
      border-color: var(--primary-dark);
      color: var(--primary-dark);
    }
    
    @media (max-width: 768px) {
      .hero-grid {
        flex-direction: column;
      }
      .hero-right {
        order: -1;
        margin-bottom: 1.5rem;
      }
    }
    
    /* 核心优势 非对称 */
    #features .feature-grid {
      display: grid;
      grid-template-columns: 1.5fr 1fr;
      gap: 2rem;
    }
    
    .feature-left {
      display: flex;
      flex-direction: column;
      justify-content: center;
    }
    
    .feature-number {
      font-family: var(--font-mono);
      font-weight: 700;
      font-size: 3rem;
      color: var(--accent-red);
      line-height: 1;
      margin-bottom: 0.5rem;
    }
    
    .feature-item {
      border-bottom: 2px solid var(--border-light);
      padding-bottom: 1.2rem;
      margin-bottom: 1.5rem;
      transition: border-color var(--transition);
    }
    
    .feature-item:hover {
      border-color: var(--accent-red);
    }
    
    .feature-right-stack {
      display: flex;
      flex-direction: column;
      gap: 1.8rem;
    }
    
    @media (max-width: 768px) {
      #features .feature-grid {
        grid-template-columns: 1fr;
      }
    }
    
    /* 服务卡片 4列 */
    .service-cards {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 1.5rem;
    }
    
    .service-card {
      background: var(--white);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-card);
      padding: 24px;
      transition: all var(--transition);
      display: flex;
      flex-direction: column;
    }
    
    .service-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
      border-color: var(--accent-red);
    }
    
    .service-icon {
      font-size: 2.2rem;
      color: var(--accent-red);
      margin-bottom: 0.8rem;
    }
    
    @media (max-width: 1024px) {
      .service-cards {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    
    @media (max-width: 520px) {
      .service-cards {
        grid-template-columns: 1fr;
      }
    }
    
    /* 统计数字 */
    #stats {
      background: #F4F5F7;
    }
    
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      text-align: center;
      gap: 2rem;
    }
    
    .stat-number {
      font-family: var(--font-mono);
      font-weight: 700;
      font-size: 3.5rem;
      color: var(--primary-dark);
      line-height: 1.2;
    }
    
    .stat-label {
      color: var(--text-gray);
      font-size: 1rem;
      margin-top: 0.5rem;
    }
    
    @media (max-width: 640px) {
      .stats-grid {
        grid-template-columns: 1fr 1fr;
      }
    }
    
    /* 流程 */
    .process-steps {
      display: flex;
      align-items: flex-start;
      justify-content: space-between;
      position: relative;
    }
    
    .process-step {
      text-align: center;
      flex: 1;
      position: relative;
    }
    
    .step-circle {
      width: 36px;
      height: 36px;
      background: var(--accent-red);
      color: white;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 0 auto 1rem;
      font-weight: 700;
    }
    
    .process-line {
      position: absolute;
      top: 18px;
      left: 50%;
      width: 100%;
      height: 2px;
      background: var(--border-light);
      z-index: -1;
    }
    
    @media (max-width: 768px) {
      .process-steps {
        flex-direction: column;
        align-items: center;
      }
      .process-line {
        display: none;
      }
    }
    
    /* FAQ */
    .accordion-title {
      background: var(--white);
      border-bottom: 1px solid var(--border-light);
      font-weight: 600;
      font-size: 1.05rem;
      color: var(--text-dark);
    }
    
    .accordion-title:hover {
      color: var(--accent-red);
    }
    
    .accordion-content {
      background: #FAFAFA;
      padding: 16px;
    }
    
    /* CTA 横幅 */
    #cta {
      background: var(--primary-dark);
      padding: 64px 0;
    }
    
    #cta h2 {
      color: white;
    }
    
    #cta .btn-primary {
      background: var(--accent-red);
      color: white;
      margin-top: 1.2rem;
    }
    
    /* 页脚 */
    #footer {
      background: #0B1E33;
      color: #B0BEC5;
      padding: 3rem 0 1.5rem;
    }
    
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 2rem;
    }
    
    #footer a {
      color: #B0BEC5;
    }
    
    #footer a:hover {
      color: white;
    }
    
    .copyright {
      border-top: 1px solid rgba(255,255,255,0.1);
      margin-top: 2rem;
      padding-top: 1.5rem;
      text-align: center;
      font-size: 0.9rem;
    }
    
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
    }