/* roulang page: index */
/* ----- 设计系统变量 ----- */
    :root {
      --primary-deep: #0A0E27;
      --primary-deep-light: #1A1F3A;
      --accent-cyan: #00F0FF;
      --accent-cyan-hover: #33F5FF;
      --accent-magenta: #FF3366;
      --accent-gold: #FFB800;
      
      --bg-dark-start: #0A0E27;
      --bg-dark-end: #1A1F3A;
      --bg-light-start: #F8F9FC;
      --bg-light-end: #FFFFFF;
      
      --text-white: #FFFFFF;
      --text-gray-light: #B0B8D0;
      --text-dark: #0A0E27;
      --text-mid: #4A5070;
      
      --card-bg-light: rgba(255,255,255,0.95);
      --card-border-light: rgba(0,240,255,0.10);
      --card-shadow: 0 8px 28px rgba(0,0,0,0.06);
      --card-shadow-hover: 0 18px 40px rgba(0,240,255,0.10);
      
      --radius-lg: 20px;
      --radius-md: 14px;
      --radius-sm: 10px;
      --radius-btn: 10px;
      
      --font-heading: 'system-ui', 'PingFang SC', 'Microsoft YaHei', '黑体', sans-serif;
      --font-body: 'system-ui', 'PingFang SC', 'Microsoft YaHei', sans-serif;
      
      --max-width: 1200px;
      --header-height: 80px;
      --section-gap: 100px;
      --card-gap: 24px;
    }
    
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    
    body {
      font-family: var(--font-body);
      background-color: var(--bg-light-start);
      color: var(--text-dark);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
      transition: background 0.2s ease;
    }
    
    /* 容器规则 */
    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
      width: 100%;
    }
    
    /* 图片强制样式 */
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s, background 0.2s, box-shadow 0.2s;
    }
    
    /* ----- 导航栏 ----- */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--header-height);
      background: rgba(10, 14, 39, 0.92);
      backdrop-filter: blur(14px);
      border-bottom: 1px solid rgba(0,240,255,0.18);
      z-index: 100;
      display: flex;
      align-items: center;
      transition: all 0.3s ease;
    }
    
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
    }
    
    .logo {
      font-family: var(--font-heading);
      font-weight: 800;
      font-size: 26px;
      letter-spacing: -0.5px;
      display: flex;
      align-items: center;
      gap: 8px;
      color: var(--text-white);
      white-space: nowrap;
    }
    
    .logo i {
      color: var(--accent-cyan);
      font-size: 32px;
      filter: drop-shadow(0 0 8px rgba(0,240,255,0.5));
    }
    
    .logo span {
      background: linear-gradient(135deg, #FFFFFF 0%, #E0F7FF 100%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }
    
    .nav-menu {
      display: flex;
      align-items: center;
      gap: 28px;
      list-style: none;
    }
    
    .nav-menu a {
      color: var(--text-gray-light);
      font-weight: 500;
      font-size: 15px;
      position: relative;
      padding: 6px 0;
      white-space: nowrap;
    }
    
    .nav-menu a::after {
      content: '';
      position: absolute;
      bottom: -2px;
      left: 50%;
      width: 0;
      height: 2px;
      background: var(--accent-cyan);
      transition: all 0.3s ease;
      transform: translateX(-50%);
      border-radius: 2px;
    }
    
    .nav-menu a:hover {
      color: var(--accent-cyan);
    }
    
    .nav-menu a:hover::after {
      width: 100%;
    }
    
    .nav-cta {
      background: var(--accent-cyan);
      color: var(--primary-deep) !important;
      font-weight: 700;
      padding: 10px 22px !important;
      border-radius: 30px;
      font-size: 14px;
      letter-spacing: 0.5px;
      border: none;
      box-shadow: 0 0 12px rgba(0,240,255,0.3);
    }
    
    .nav-cta:hover {
      background: var(--accent-cyan-hover);
      box-shadow: 0 0 20px rgba(0,240,255,0.6);
    }
    
    .hamburger {
      display: none;
      flex-direction: column;
      cursor: pointer;
      gap: 6px;
      background: none;
      border: none;
    }
    
    .hamburger span {
      width: 26px;
      height: 2.5px;
      background: var(--text-white);
      transition: 0.3s;
      border-radius: 2px;
    }
    
    /* 移动端导航全屏抽屉 */
    .mobile-nav-overlay {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100vh;
      background: rgba(10,14,39,0.97);
      backdrop-filter: blur(20px);
      z-index: 99;
      flex-direction: column;
      justify-content: center;
      align-items: center;
      gap: 30px;
    }
    
    .mobile-nav-overlay.active {
      display: flex;
    }
    
    .mobile-nav-overlay a {
      font-size: 22px;
      color: var(--text-white);
      font-weight: 500;
      letter-spacing: 1px;
    }
    
    /* ----- 各区块共用样式 ----- */
    .section {
      padding-top: var(--section-gap);
      padding-bottom: var(--section-gap);
    }
    
    .section-dark {
      background: linear-gradient(135deg, #0A0E27 0%, #141834 100%);
      color: var(--text-white);
    }
    
    .section-light {
      background: #FFFFFF;
    }
    
    .section-hero {
      padding-top: calc(var(--header-height) + 60px);
      padding-bottom: 80px;
    }
    
    .section-title {
      font-family: var(--font-heading);
      font-weight: 800;
      font-size: 2.4rem;
      letter-spacing: -0.5px;
      margin-bottom: 16px;
      line-height: 1.3;
      color: inherit;
    }
    
    .section-desc {
      color: var(--text-mid);
      font-size: 1.1rem;
      max-width: 700px;
      margin-bottom: 32px;
    }
    
    .dark-text {
      color: var(--text-gray-light);
    }
    
    .highlight {
      color: var(--accent-cyan);
    }
    
    /* 卡片基础 */
    .card-grid {
      display: grid;
      gap: var(--card-gap);
    }
    
    .card {
      background: var(--card-bg-light);
      border-radius: var(--radius-lg);
      padding: 32px 24px;
      border: 1px solid var(--card-border-light);
      box-shadow: var(--card-shadow);
      transition: transform 0.25s ease, box-shadow 0.3s;
    }
    
    .card:hover {
      transform: translateY(-6px);
      box-shadow: var(--card-shadow-hover);
      border-color: rgba(0,240,255,0.25);
    }
    
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      font-weight: 600;
      border-radius: var(--radius-btn);
      transition: 0.2s ease;
      cursor: pointer;
      border: none;
    }
    
    .btn-primary {
      background: var(--accent-cyan);
      color: #0A0E27;
      padding: 14px 34px;
      box-shadow: 0 0 16px rgba(0,240,255,0.35);
    }
    
    .btn-primary:hover {
      background: #33F5FF;
      box-shadow: 0 0 28px rgba(0,240,255,0.65);
      transform: scale(1.03);
    }
    
    .btn-outline {
      background: transparent;
      border: 2px solid var(--accent-cyan);
      color: var(--accent-cyan);
      padding: 12px 32px;
    }
    
    .btn-outline:hover {
      background: rgba(0,240,255,0.08);
    }
    
    /* 数据徽章 */
    .badge-glow {
      background: rgba(0,240,255,0.12);
      color: var(--accent-cyan);
      padding: 6px 14px;
      border-radius: 20px;
      font-weight: 600;
      font-size: 0.85rem;
      backdrop-filter: blur(4px);
    }
    
    /* Hero区 */
    .hero-content {
      display: flex;
      align-items: center;
      gap: 50px;
      flex-wrap: wrap;
    }
    
    .hero-left {
      flex: 1 1 45%;
    }
    
    .hero-right {
      flex: 1 1 40%;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      border-radius: var(--radius-lg);
      min-height: 380px;
      box-shadow: 0 0 40px rgba(0,240,255,0.15);
    }
    
    /* FAQ */
    .faq-item {
      border-bottom: 1px solid rgba(0,240,255,0.18);
      padding: 16px 0;
    }
    
    .faq-question {
      font-weight: 700;
      font-size: 1.2rem;
      display: flex;
      justify-content: space-between;
      cursor: pointer;
      color: var(--text-white);
    }
    
    /* 响应式 */
    @media (max-width: 992px) {
      .nav-menu {
        display: none;
      }
      .hamburger {
        display: flex;
      }
      .hero-content {
        flex-direction: column;
      }
    }