/* roulang page: index */
/* ----- 设计变量 & 重置 ----- */
    :root {
      --deep-space: #0B0E14;
      --darker-space: #070A10;
      --star-silver: #B0C4DE;
      --aurora-cyan: #00E5FF;
      --aurora-glow: rgba(0, 229, 255, 0.25);
      --nebula-gray: rgba(255, 255, 255, 0.05);
      --border-dim: rgba(255, 255, 255, 0.1);
      --border-hover: rgba(0, 229, 255, 0.4);
      --text-primary: #FFFFFF;
      --text-secondary: rgba(255, 255, 255, 0.7);
      --text-muted: rgba(255, 255, 255, 0.45);
      --radius-lg: 24px;
      --radius-md: 16px;
      --radius-sm: 12px;
      --radius-pill: 50px;
      --shadow-card: 0 25px 45px -15px rgba(0, 0, 0, 0.5);
      --shadow-glow: 0 20px 40px -15px rgba(0, 229, 255, 0.25);
      --transition-smooth: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1.2);
      --font-body: "Inter", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --font-display: "Space Grotesk", "DIN Alternate", "Roboto Mono", "PingFang SC", sans-serif;
      --container-max: 1280px;
    }

    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }

    html {
      scroll-behavior: smooth;
      background-color: var(--deep-space);
    }

    body {
      font-family: var(--font-body);
      background-color: var(--deep-space);
      color: var(--text-secondary);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
    }

    img {
      max-width: 100%;
      height: auto;
      display: block;
    }

    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition-smooth);
    }

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: none;
    }

    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 2rem;
    }

    /* 板块通用间距 */
    .section {
      padding: 7rem 0;
    }
    .section-label {
      font-size: 0.9rem;
      text-transform: uppercase;
      letter-spacing: 0.2em;
      color: var(--aurora-cyan);
      margin-bottom: 1rem;
      font-weight: 600;
    }
    .section-title {
      font-family: var(--font-display);
      font-size: clamp(2.2rem, 5vw, 3rem);
      font-weight: 600;
      color: var(--star-silver);
      margin-bottom: 1.5rem;
      line-height: 1.2;
    }
    .section-desc {
      font-size: 1.15rem;
      color: var(--text-secondary);
      max-width: 700px;
      margin: 0 auto 3.5rem auto;
      text-align: center;
    }

    /* 按钮样式 */
    .btn-primary {
      background: var(--aurora-cyan);
      color: var(--deep-space);
      font-weight: 600;
      padding: 0.9rem 2.8rem;
      border-radius: var(--radius-pill);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 0.5rem;
      transition: var(--transition-smooth);
      box-shadow: 0 8px 20px -8px rgba(0, 229, 255, 0.3);
      letter-spacing: 0.03em;
      font-size: 1rem;
    }
    .btn-primary:hover {
      background: #33f0ff;
      box-shadow: 0 0 35px rgba(0, 229, 255, 0.7);
      transform: translateY(-2px);
    }

    .btn-ghost {
      background: transparent;
      border: 1px solid var(--aurora-cyan);
      color: var(--aurora-cyan);
      padding: 0.65rem 1.8rem;
      border-radius: var(--radius-pill);
      font-weight: 500;
      backdrop-filter: blur(8px);
    }
    .btn-ghost:hover {
      background: rgba(0, 229, 255, 0.1);
      border-color: #fff;
      color: #fff;
    }

    /* ----- 导航栏 SaaS 命令栏风格 ----- */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 50;
      background: rgba(11, 14, 20, 0.75);
      backdrop-filter: saturate(180%) blur(24px);
      -webkit-backdrop-filter: saturate(180%) blur(24px);
      border-bottom: 1px solid rgba(255, 255, 255, 0.06);
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 0.9rem 2rem;
      max-width: var(--container-max);
      margin: 0 auto;
    }
    .logo {
      font-family: var(--font-display);
      font-size: 1.8rem;
      font-weight: 700;
      color: #fff;
      letter-spacing: 0.02em;
      display: flex;
      align-items: center;
      gap: 0.4rem;
    }
    .logo i {
      color: var(--aurora-cyan);
      font-size: 2rem;
    }
    .nav-links {
      display: flex;
      gap: 2.5rem;
      align-items: center;
    }
    .nav-links a {
      font-weight: 500;
      color: var(--text-secondary);
      font-size: 0.95rem;
      position: relative;
      padding: 0.25rem 0;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--aurora-cyan);
      transition: width 0.25s ease;
    }
    .nav-links a:hover {
      color: #fff;
    }
    .nav-links a:hover::after {
      width: 100%;
    }
    .header-actions {
      display: flex;
      align-items: center;
      gap: 1.2rem;
    }
    .search-trigger {
      color: var(--star-silver);
      font-size: 1.2rem;
      transition: color 0.2s;
      background: none;
      border: none;
      cursor: pointer;
    }
    .search-trigger:hover {
      color: var(--aurora-cyan);
    }
    .mobile-menu-btn {
      display: none;
      font-size: 1.6rem;
      color: #fff;
      background: none;
      border: none;
    }

    /* 移动端导航 */
    @media (max-width: 768px) {
      .nav-links {
        display: none;
      }
      .mobile-menu-btn {
        display: block;
      }
      .header-actions .btn-ghost {
        display: none;
      }
    }

    /* ----- Hero 首屏 ----- */
    .hero {
      display: flex;
      align-items: center;
      min-height: 90vh;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      position: relative;
      overflow: hidden;
    }
    .hero::before {
      content: '';
      position: absolute;
      inset: 0;
      background: radial-gradient(circle at 30% 40%, rgba(0,229,255,0.08) 0%, rgba(11,14,20,0.75) 70%);
    }
    .hero-content {
      position: relative;
      z-index: 2;
      max-width: 700px;
      padding: 2rem 0;
    }
    .hero h1 {
      font-family: var(--font-display);
      font-size: clamp(3.2rem, 8vw, 5.2rem);
      font-weight: 700;
      color: #FFFFFF;
      line-height: 1.1;
      margin-bottom: 1.8rem;
      letter-spacing: -0.01em;
    }
    .hero p {
      font-size: 1.25rem;
      color: rgba(255,255,255,0.75);
      margin-bottom: 2.5rem;
      max-width: 550px;
    }
    .hero .btn-primary {
      padding: 1rem 3.2rem;
      font-size: 1.1rem;
    }

    /* ----- 服务板块：行星轨道隐喻 (错落悬浮) ----- */
    .services-grid {
      display: flex;
      flex-wrap: wrap;
      justify-content: center;
      gap: 2rem;
      margin-top: 2rem;
    }
    .service-card {
      background: var(--nebula-gray);
      backdrop-filter: blur(16px);
      border: 1px solid var(--border-dim);
      border-radius: var(--radius-lg);
      padding: 2.5rem 2rem;
      flex: 1 1 240px;
      max-width: 300px;
      text-align: center;
      transition: var(--transition-smooth);
      position: relative;
    }
    .service-card:nth-child(odd) {
      transform: translateY(-18px);
    }
    .service-card:nth-child(even) {
      transform: translateY(18px);
    }
    .service-card:hover {
      border-color: var(--aurora-cyan);
      box-shadow: var(--shadow-glow);
      transform: translateY(-12px) scale(1.02);
    }
    .service-icon {
      font-size: 2.8rem;
      color: var(--aurora-cyan);
      margin-bottom: 1.5rem;
    }
    .service-card h3 {
      font-family: var(--font-display);
      color: #fff;
      font-size: 1.5rem;
      margin-bottom: 0.8rem;
    }

    /* ----- 引力数据 ----- */
    .stats-grid {
      display: flex;
      flex-wrap: wrap;
      justify-content: center;
      gap: 3rem;
      text-align: center;
    }
    .stat-item {
      flex: 1 1 180px;
    }
    .stat-number {
      font-family: var(--font-display);
      font-size: 3.2rem;
      font-weight: 700;
      color: var(--aurora-cyan);
      display: block;
    }

    /* ----- 星云案例 ----- */
    .case-row {
      display: flex;
      align-items: center;
      gap: 3rem;
      margin-bottom: 4rem;
      flex-wrap: wrap;
    }
    .case-img {
      flex: 1 1 45%;
      border-radius: var(--radius-lg);
      overflow: hidden;
      box-shadow: var(--shadow-card);
    }
    .case-text {
      flex: 1 1 45%;
    }

    /* ----- FAQ 手风琴 ----- */
    .faq-grid {
      display: flex;
      gap: 3rem;
      flex-wrap: wrap;
    }
    .faq-categories {
      flex: 1 1 200px;
    }
    .faq-list {
      flex: 2 1 500px;
    }
    .faq-item {
      border-bottom: 1px solid var(--border-dim);
      padding: 1.2rem 0;
      cursor: pointer;
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      font-weight: 600;
      color: #fff;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease, padding 0.2s;
      color: var(--text-secondary);
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-top: 12px;
    }

    /* ----- 页脚 ----- */
    .site-footer {
      background: var(--darker-space);
      padding: 3rem 0;
      text-align: center;
      border-top: 1px solid rgba(255,255,255,0.05);
    }

    @media (max-width: 768px) {
      .hero {
        text-align: center;
      }
      .service-card:nth-child(odd), .service-card:nth-child(even) {
        transform: none;
      }
      .case-row {
        flex-direction: column;
      }
    }