/* roulang page: index */
/* ----- 设计变量 / 基础重置 ----- */
    :root {
      --bg-deep: #0A0E17;
      --surface: #131A26;
      --surface-hover: #1A2436;
      --primary: #C84BFA;
      --primary-glow: rgba(200,75,250,0.6);
      --secondary: #00F0FF;
      --accent: #FF3A5C;
      --text-primary: #FFFFFF;
      --text-body: #B0C4DE;
      --text-muted: #6B7A8F;
      --border-subtle: rgba(200,75,250,0.15);
      --border-active: rgba(200,75,250,0.4);
      --radius-card: 12px;
      --radius-btn: 8px;
      --shadow-card: 0 4px 24px rgba(0,0,0,0.4);
      --shadow-hover: 0 8px 32px rgba(200,75,250,0.25);
      --container-max: 1200px;
      --gap-section: 100px;
      --gap-mobile: 60px;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    html {
      scroll-behavior: smooth;
    }
    body {
      font-family: 'Inter', 'PingFang SC', 'Microsoft YaHei', 'Hiragino Sans GB', sans-serif;
      background-color: var(--bg-deep);
      color: var(--text-body);
      line-height: 1.75;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    button, input {
      font-family: inherit;
    }
    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }
    /* 排版 */
    h1, h2, h3 {
      font-weight: 700;
      letter-spacing: -0.02em;
      color: var(--text-primary);
    }
    h1 { font-size: 48px; line-height: 1.2; }
    h2 { font-size: 36px; line-height: 1.3; margin-bottom: 16px; }
    h3 { font-size: 22px; line-height: 1.4; }
    .text-muted { color: var(--text-muted); }
    .text-glow { color: var(--primary); }
    .text-cyan { color: var(--secondary); }
    .section {
      padding: var(--gap-section) 0;
    }
    @media (max-width: 768px) {
      h1 { font-size: 32px; }
      h2 { font-size: 24px; }
      h3 { font-size: 18px; }
      .section { padding: var(--gap-mobile) 0; }
      .container { padding: 0 20px; }
    }
    /* 按钮系统 */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      font-weight: 600;
      border-radius: var(--radius-btn);
      padding: 14px 32px;
      transition: all 0.2s ease;
      cursor: pointer;
      border: none;
      font-size: 16px;
      min-height: 48px;
    }
    .btn-primary {
      background: var(--primary);
      color: #fff;
      box-shadow: 0 0 20px rgba(200,75,250,0.4);
    }
    .btn-primary:hover {
      background: #D96FFF;
      box-shadow: 0 0 24px var(--primary-glow);
    }
    .btn-secondary {
      background: transparent;
      border: 1px solid var(--secondary);
      color: var(--secondary);
    }
    .btn-secondary:hover {
      background: rgba(0,240,255,0.1);
      border-color: #33f5ff;
    }
    .btn-ghost {
      background: transparent;
      border: 1px solid rgba(255,255,255,0.3);
      color: #fff;
    }
    .btn-ghost:hover {
      border-color: var(--secondary);
      color: var(--secondary);
      background: rgba(0,240,255,0.05);
    }
    .btn-lg { padding: 18px 48px; font-size: 18px; }
    /* 卡片 */
    .card {
      background: var(--surface);
      border: 1px solid var(--border-subtle);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      transition: all 0.25s ease;
    }
    .card:hover {
      border-color: var(--primary);
      box-shadow: var(--shadow-hover);
    }
    /* 导航 */
    .navbar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 64px;
      background: rgba(10,14,23,0.85);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      display: flex;
      align-items: center;
      justify-content: center;
      z-index: 1000;
      border-bottom: 1px solid rgba(200,75,250,0.1);
    }
    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
      max-width: var(--container-max);
      padding: 0 24px;
    }
    .logo {
      font-weight: 700;
      font-size: 24px;
      color: var(--primary);
      letter-spacing: -0.5px;
    }
    .nav-links {
      display: flex;
      gap: 28px;
      align-items: center;
    }
    .nav-links a {
      color: var(--text-body);
      font-weight: 500;
      font-size: 15px;
      transition: color 0.2s;
      position: relative;
    }
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--secondary);
    }
    .nav-links a.active::after {
      content: '';
      position: absolute;
      bottom: -6px;
      left: 0;
      width: 100%;
      height: 2px;
      background: var(--secondary);
    }
    .menu-toggle {
      display: none;
      background: none;
      border: none;
      color: #fff;
      font-size: 24px;
      cursor: pointer;
    }
    @media (max-width: 768px) {
      .nav-links {
        position: fixed;
        top: 64px;
        left: 0;
        width: 100%;
        background: rgba(10,14,23,0.98);
        flex-direction: column;
        padding: 32px;
        gap: 24px;
        transform: translateY(-150%);
        transition: transform 0.3s ease;
        backdrop-filter: blur(20px);
      }
      .nav-links.open {
        transform: translateY(0);
      }
      .menu-toggle {
        display: block;
      }
      .nav-links a {
        font-size: 18px;
      }
    }
    /* Hero */
    .hero {
      min-height: 100vh;
      display: flex;
      align-items: center;
      background: radial-gradient(circle at 20% 30%, rgba(200,75,250,0.15) 0%, transparent 50%),
                  radial-gradient(circle at 80% 70%, rgba(0,240,255,0.08) 0%, transparent 50%);
      background-color: var(--bg-deep);
      position: relative;
      overflow: hidden;
    }
    .hero-content {
      display: flex;
      align-items: center;
      gap: 48px;
      flex-wrap: wrap;
    }
    .hero-text {
      flex: 1 1 500px;
    }
    .hero-visual {
      flex: 1 1 400px;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      border-radius: 24px;
      min-height: 350px;
      position: relative;
      box-shadow: 0 0 40px rgba(0,0,0,0.6);
    }
    .hero-visual::after {
      content: '';
      position: absolute;
      inset: 0;
      background: rgba(10,14,23,0.5);
      border-radius: 24px;
    }
    .hero h1 {
      margin-bottom: 18px;
    }
    .hero .subtitle {
      font-size: 18px;
      color: var(--text-body);
      margin-bottom: 32px;
      max-width: 550px;
    }
    .btn-group {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    @media (max-width: 768px) {
      .hero-content {
        flex-direction: column;
        text-align: center;
        padding: 80px 0 40px;
      }
      .hero-visual {
        width: 100%;
        min-height: 250px;
      }
      .btn-group {
        justify-content: center;
      }
    }
    /* 数据仪表盘优势 */
    .stats-grid {
      display: flex;
      justify-content: space-around;
      text-align: center;
      gap: 24px;
      flex-wrap: wrap;
    }
    .stat-item {
      flex: 1 1 200px;
      padding: 24px 12px;
    }
    .stat-number {
      font-size: 64px;
      font-weight: 700;
      color: var(--secondary);
      line-height: 1.1;
      font-family: 'Inter', sans-serif;
    }
    .stat-label {
      color: var(--text-body);
      margin-top: 8px;
      font-weight: 500;
    }
    .divider-vertical {
      width: 1px;
      background: rgba(200,75,250,0.25);
      margin: 0 12px;
    }
    @media (max-width: 768px) {
      .stat-number { font-size: 40px; }
      .divider-vertical { display: none; }
      .stats-grid { flex-direction: column; }
    }
    /* 非对称功能网格 */
    .feature-grid {
      display: grid;
      grid-template-columns: 2fr 1fr;
      gap: 24px;
      margin-top: 32px;
    }
    .feature-item {
      background: var(--surface);
      border: 1px solid var(--border-subtle);
      border-radius: var(--radius-card);
      padding: 32px;
      display: flex;
      flex-direction: column;
      transition: 0.25s;
    }
    .feature-item.wide {
      grid-column: span 1;
      flex-direction: row;
      align-items: center;
      gap: 32px;
    }
    .feature-img {
      width: 45%;
      background-image: url('/assets/images/coverpic/cover-1.webp');
      background-size: cover;
      background-position: center;
      border-radius: 12px;
      min-height: 220px;
      position: relative;
    }
    .feature-img::after {
      content: '';
      position: absolute;
      inset: 0;
      background: linear-gradient(to right, rgba(19,26,38,0.7), transparent);
      border-radius: 12px;
    }
    .feature-text {
      flex: 1;
    }
    @media (max-width: 1024px) {
      .feature-grid {
        grid-template-columns: 1fr;
      }
      .feature-item.wide {
        flex-direction: column;
      }
      .feature-img {
        width: 100%;
        min-height: 200px;
      }
    }
    /* 场景卡片横向滚动 */
    .scenario-scroll {
      display: flex;
      gap: 20px;
      overflow-x: auto;
      padding: 16px 0 24px;
      scrollbar-width: thin;
      scrollbar-color: var(--primary) var(--surface);
    }
    .scenario-card {
      min-width: 300px;
      height: 240px;
      border-radius: 16px;
      background-size: cover;
      background-position: center;
      position: relative;
      overflow: hidden;
      flex-shrink: 0;
      display: flex;
      align-items: flex-end;
      padding: 20px;
    }
    .scenario-card::before {
      content: '';
      position: absolute;
      inset: 0;
      background: linear-gradient(to top, rgba(0,0,0,0.8), transparent);
      transition: 0.3s;
    }
    .scenario-card:hover::before {
      background: linear-gradient(to top, rgba(0,0,0,0.5), transparent);
    }
    .scenario-card h3 {
      position: relative;
      color: white;
      z-index: 2;
    }
    .bg-cover1 { background-image: url('/assets/images/coverpic/cover-2.webp'); }
    .bg-cover2 { background-image: url('/assets/images/coverpic/cover-3.webp'); }
    .bg-cover3 { background-image: url('/assets/images/coverpic/cover-4.webp'); }
    /* 案例数据 */
    .case-layout {
      display: flex;
      gap: 48px;
      align-items: center;
      flex-wrap: wrap;
    }
    .case-stats {
      flex: 1;
    }
    .logo-wall {
      display: grid;
      grid-template-columns: repeat(4,1fr);
      gap: 16px;
      flex: 1;
    }
    .logo-item {
      background: rgba(255,255,255,0.05);
      border-radius: 8px;
      height: 48px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: var(--text-muted);
      font-weight: 600;
      transition: 0.2s;
    }
    .logo-item:hover {
      background: rgba(200,75,250,0.15);
      color: white;
    }
    /* FAQ 手风琴 */
    .faq-item {
      border-bottom: 1px solid var(--border-subtle);
    }
    .faq-question {
      width: 100%;
      background: transparent;
      border: none;
      padding: 20px 8px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
      font-size: 18px;
      color: var(--text-primary);
      cursor: pointer;
      text-align: left;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      padding: 0 8px;
      color: var(--text-body);
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-bottom: 24px;
    }
    .faq-icon {
      color: var(--secondary);
    }
    /* 最终 CTA */
    .cta-final {
      background: radial-gradient(circle at center, rgba(200,75,250,0.2), transparent);
      text-align: center;
      padding: 80px 0;
    }
    /* 页脚 */
    .footer {
      background: #0A0E17;
      border-top: 1px solid rgba(200,75,250,0.2);
      padding: 48px 0 24px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 32px;
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr;
      }
      .case-layout {
        flex-direction: column;
      }
      .logo-wall {
        grid-template-columns: repeat(3,1fr);
      }
    }
    .footer a {
      color: var(--text-muted);
      font-size: 14px;
    }
    .footer a:hover {
      color: var(--secondary);
    }
    .copyright {
      margin-top: 32px;
      font-size: 13px;
      color: var(--text-muted);
    }
    /* 辅助类 */
    .mt-16 { margin-top: 16px; }
    .mb-24 { margin-bottom: 24px; }
    .gap-24 { gap: 24px; }