/* roulang page: index */
/* ----- 设计变量与重置 ----- */
    :root {
      --bg-deep: #0A0E27;
      --bg-darker: #060A1A;
      --primary-cyan: #00F0FF;
      --secondary-violet: #7B2FFF;
      --surface-glass: rgba(255,255,255,0.05);
      --border-glass: rgba(255,255,255,0.12);
      --text-primary: #FFFFFF;
      --text-secondary: rgba(255,255,255,0.7);
      --text-muted: rgba(255,255,255,0.45);
      --shadow-glow: 0 0 30px rgba(0,240,255,0.08);
      --shadow-glow-hover: 0 0 40px rgba(0,240,255,0.25);
      --radius-card: 16px;
      --radius-btn: 8px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
      --font-number: "DIN Alternate", "PingFang SC", sans-serif;
    }

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

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

    body {
      font-family: var(--font-sans);
      background: var(--bg-deep);
      color: var(--text-secondary);
      line-height: 1.75;
      min-height: 100vh;
      -webkit-font-smoothing: antialiased;
    }

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

    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s ease;
    }

    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }

    /* 玻璃拟态卡片基础 */
    .glass-card {
      background: rgba(255,255,255,0.04);
      backdrop-filter: blur(20px);
      -webkit-backdrop-filter: blur(20px);
      border: 1px solid rgba(255,255,255,0.08);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-glow);
      transition: all 0.3s ease;
    }

    .glass-card:hover {
      border-color: rgba(0,240,255,0.25);
      box-shadow: var(--shadow-glow-hover);
      transform: translateY(-4px);
    }

    /* 按钮系统 */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      font-weight: 600;
      letter-spacing: 0.5px;
      border-radius: var(--radius-btn);
      padding: 14px 32px;
      cursor: pointer;
      border: none;
      transition: all 0.3s ease;
      font-size: 16px;
      line-height: 1.2;
      text-align: center;
    }

    .btn-primary {
      background: var(--primary-cyan);
      color: var(--bg-deep);
      box-shadow: 0 0 20px rgba(0,240,255,0.5);
    }

    .btn-primary:hover {
      background: #33F5FF;
      box-shadow: 0 0 30px rgba(0,240,255,0.7);
      color: #0A0E27;
    }

    .btn-secondary {
      background: transparent;
      border: 1px solid var(--secondary-violet);
      color: var(--secondary-violet);
      box-shadow: none;
    }

    .btn-secondary:hover {
      border-color: var(--primary-cyan);
      color: var(--primary-cyan);
      box-shadow: 0 0 18px rgba(0,240,255,0.3);
    }

    .btn-lg {
      font-size: 18px;
      padding: 18px 40px;
    }

    /* 区块标题 */
    .section-title {
      font-size: 32px;
      font-weight: 700;
      color: var(--text-primary);
      text-align: center;
      margin-bottom: 16px;
      position: relative;
      display: inline-block;
      left: 50%;
      transform: translateX(-50%);
    }

    .section-title::after {
      content: '';
      position: absolute;
      bottom: -8px;
      left: 50%;
      transform: translateX(-50%);
      width: 40px;
      height: 4px;
      background: var(--primary-cyan);
      border-radius: 2px;
    }

    .section-subtitle {
      text-align: center;
      color: var(--text-secondary);
      max-width: 600px;
      margin: 24px auto 48px;
      font-size: 16px;
    }

    /* 导航 */
    .header {
      position: sticky;
      top: 0;
      z-index: 100;
      background: rgba(10,14,39,0.85);
      backdrop-filter: blur(15px);
      -webkit-backdrop-filter: blur(15px);
      border-bottom: 1px solid rgba(255,255,255,0.06);
    }

    .nav-bar {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }

    .logo {
      font-size: 24px;
      font-weight: 700;
      color: var(--primary-cyan);
      letter-spacing: 0.5px;
      white-space: nowrap;
    }

    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
    }

    .nav-links a {
      font-size: 15px;
      color: rgba(255,255,255,0.75);
      padding: 8px 0;
      position: relative;
      font-weight: 500;
    }

    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--primary-cyan);
      transition: width 0.2s ease;
    }

    .nav-links a:hover {
      color: var(--primary-cyan);
    }

    .nav-links a:hover::after {
      width: 100%;
    }

    .menu-toggle {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: transparent;
      border: none;
      cursor: pointer;
      padding: 8px;
    }

    .menu-toggle span {
      display: block;
      width: 25px;
      height: 2px;
      background: var(--primary-cyan);
      transition: 0.3s;
    }

    /* 移动端导航面板 */
    .mobile-menu {
      display: none;
      position: fixed;
      top: 72px;
      left: 0;
      width: 100%;
      background: rgba(10,14,39,0.95);
      backdrop-filter: blur(20px);
      flex-direction: column;
      padding: 32px 24px;
      gap: 24px;
      border-bottom: 1px solid rgba(255,255,255,0.08);
      z-index: 99;
    }

    .mobile-menu a {
      font-size: 18px;
      color: rgba(255,255,255,0.8);
      font-weight: 500;
    }

    /* Hero */
    .hero {
      background: radial-gradient(circle at 50% 30%, rgba(0,240,255,0.12), transparent 70%), var(--bg-deep);
      padding: 120px 0 100px;
      position: relative;
      overflow: hidden;
    }

    .hero-content {
      position: relative;
      z-index: 2;
      text-align: center;
    }

    .hero h1 {
      font-size: 48px;
      font-weight: 700;
      line-height: 1.2;
      color: var(--text-primary);
      letter-spacing: -0.5px;
      margin-bottom: 24px;
    }

    .hero p {
      font-size: 18px;
      color: rgba(255,255,255,0.65);
      max-width: 620px;
      margin: 0 auto 40px;
    }

    .btn-group {
      display: flex;
      gap: 16px;
      justify-content: center;
      flex-wrap: wrap;
    }

    /* 动态粒子背景 */
    .particles {
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      overflow: hidden;
      z-index: 1;
      pointer-events: none;
    }

    .particle {
      position: absolute;
      background: var(--primary-cyan);
      opacity: 0.15;
      border-radius: 50%;
      animation: float 8s infinite;
    }

    @keyframes float {
      0% { transform: translateY(0) scale(1); }
      50% { transform: translateY(-20px) scale(1.1); }
      100% { transform: translateY(0) scale(1); }
    }

    /* 服务区块 非对称布局尝试 */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }

    .service-card {
      padding: 32px 24px;
      display: flex;
      flex-direction: column;
      align-items: flex-start;
    }

    .service-icon {
      width: 48px;
      height: 48px;
      margin-bottom: 20px;
      color: var(--primary-cyan);
    }

    .service-card h3 {
      font-size: 20px;
      font-weight: 600;
      color: var(--text-primary);
      margin-bottom: 12px;
    }

    /* 数据优势 */
    .advantages {
      display: flex;
      justify-content: space-around;
      flex-wrap: wrap;
      gap: 32px;
      text-align: center;
    }

    .adv-item .adv-number {
      font-family: var(--font-number);
      font-size: 42px;
      font-weight: 800;
      color: var(--primary-cyan);
      line-height: 1.2;
    }

    /* 流程 */
    .process-steps {
      display: flex;
      justify-content: center;
      align-items: flex-start;
      gap: 40px;
      flex-wrap: wrap;
    }

    .step {
      display: flex;
      flex-direction: column;
      align-items: center;
      text-align: center;
      max-width: 200px;
    }

    .step-circle {
      width: 48px;
      height: 48px;
      border: 2px solid var(--primary-cyan);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      color: white;
      margin-bottom: 16px;
    }

    /* 案例卡片 */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }

    .case-card {
      background: rgba(255,255,255,0.04);
      backdrop-filter: blur(16px);
      border: 1px solid rgba(255,255,255,0.08);
      border-radius: var(--radius-card);
      overflow: hidden;
    }

    .case-img {
      height: 180px;
      background-size: cover;
      background-position: center;
      position: relative;
    }

    .case-tag {
      background: rgba(0,240,255,0.15);
      color: var(--primary-cyan);
      font-size: 12px;
      padding: 4px 12px;
      border-radius: 20px;
      display: inline-block;
      margin: 16px 16px 8px;
    }

    /* FAQ */
    .faq-item {
      margin-bottom: 12px;
    }

    .faq-question {
      background: rgba(255,255,255,0.03);
      padding: 20px;
      border-left: 3px solid var(--primary-cyan);
      font-weight: 600;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }

    .faq-answer {
      background: rgba(255,255,255,0.02);
      padding: 0 20px;
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, padding 0.3s ease;
    }

    .faq-item.open .faq-answer {
      max-height: 200px;
      padding: 20px;
    }

    /* CTA */
    .cta-section {
      background: linear-gradient(135deg, rgba(123,47,255,0.08), rgba(0,240,255,0.08)), var(--bg-deep);
    }

    /* Footer */
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }

    @media (max-width: 1024px) {
      .services-grid, .cases-grid {
        grid-template-columns: repeat(2, 1fr);
      }
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
    }

    @media (max-width: 768px) {
      .nav-links { display: none; }
      .menu-toggle { display: flex; }
      .hero h1 { font-size: 32px; }
      .section-title { font-size: 24px; }
      .services-grid, .cases-grid { grid-template-columns: 1fr; }
      .btn-group { flex-direction: column; align-items: center; }
      .btn { width: 100%; max-width: 280px; }
      .footer-grid { grid-template-columns: 1fr; }
      .container { padding: 0 16px; }
    }