/* roulang page: index */
:root {
      --bg-deep: #0A1929;
      --bg-card: #1E3A5F;
      --accent: #00C2FF;
      --metal-light: #B8D4E3;
      --text-primary: #E6F1F5;
      --text-secondary: #8BA4B5;
      --text-muted: #5A7A8A;
      --gradient-accent: linear-gradient(135deg, #00C2FF 0%, #0078D4 100%);
      --card-glass: rgba(30, 58, 95, 0.45);
      --border-glass: rgba(184, 212, 227, 0.15);
      --shadow-card: 0 8px 32px rgba(0,0,0,0.4);
      --shadow-glow: 0 0 18px rgba(0,194,255,0.5);
      --radius-card: 16px;
      --radius-btn: 30px;
      --radius-input: 10px;
      --radius-icon: 12px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --font-mono: "Inter", "SF Pro Display", sans-serif;
      --transition-fast: 0.2s ease;
      --transition-smooth: 0.3s ease;
    }
    * {
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--bg-deep);
      color: var(--text-primary);
      line-height: 1.7;
      margin: 0;
      overflow-x: hidden;
    }
    h1, h2, h3, h4, h5, h6 {
      font-weight: 600;
      color: var(--text-primary);
      line-height: 1.3;
    }
    h1 {
      font-size: 48px;
      font-weight: 700;
      background: var(--gradient-accent);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
      display: inline-block;
    }
    h2 {
      font-size: 36px;
      color: var(--text-primary);
      margin-bottom: 2rem;
    }
    h3 {
      font-size: 22px;
      color: var(--text-primary);
    }
    p, .text-body {
      color: var(--text-secondary);
      font-size: 16px;
      line-height: 1.7;
    }
    .small-text {
      font-size: 13px;
      color: var(--text-secondary);
      letter-spacing: 0.5px;
    }
    a {
      color: var(--accent);
      text-decoration: none;
      transition: var(--transition-fast);
    }
    a:hover {
      color: #33d6ff;
      text-decoration: underline;
    }
    .container-custom {
      max-width: 1140px;
      margin: 0 auto;
      padding: 0 20px;
    }
    /* 导航栏 - 分段标签风格 */
    .navbar-custom {
      position: sticky;
      top: 0;
      z-index: 1000;
      background: rgba(10, 25, 41, 0.75);
      backdrop-filter: blur(20px);
      -webkit-backdrop-filter: blur(20px);
      border-bottom: 1px solid rgba(184, 212, 227, 0.1);
      padding: 12px 0;
    }
    .nav-logo {
      font-family: var(--font-mono);
      font-weight: 700;
      font-size: 28px;
      color: var(--accent);
      display: flex;
      align-items: center;
      gap: 6px;
      text-decoration: none;
    }
    .nav-logo:hover {
      color: #33d6ff;
      text-decoration: none;
    }
    .nav-logo i {
      font-size: 30px;
      color: var(--accent);
    }
    .nav-chips {
      display: flex;
      gap: 8px;
      flex-wrap: wrap;
      align-items: center;
    }
    .nav-chip {
      background: rgba(30, 58, 95, 0.6);
      border-radius: 20px;
      padding: 6px 16px;
      color: var(--metal-light);
      font-weight: 500;
      font-size: 14px;
      transition: var(--transition-smooth);
      text-decoration: none;
      border: none;
      white-space: nowrap;
    }
    .nav-chip:hover, .nav-chip.active {
      background: var(--accent);
      color: #0A1929;
      text-decoration: none;
    }
    .btn-cta-nav {
      background: var(--gradient-accent);
      border: none;
      border-radius: var(--radius-btn);
      padding: 8px 24px;
      color: white;
      font-weight: 600;
      font-size: 15px;
      transition: var(--transition-smooth);
      box-shadow: 0 0 12px rgba(0,194,255,0.4);
      white-space: nowrap;
    }
    .btn-cta-nav:hover {
      box-shadow: var(--shadow-glow);
      transform: translateY(-2px);
      color: white;
    }
    /* Hero */
    .hero-section {
      padding: 80px 0 100px;
      background: radial-gradient(circle at 20% 30%, rgba(0,194,255,0.08) 0%, transparent 50%);
    }
    .hero-title-wrapper h1 {
      background: none;
      -webkit-text-fill-color: var(--text-primary);
      color: var(--text-primary);
    }
    .hero-title-wrapper h1 span {
      background: var(--gradient-accent);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }
    .hero-subtitle {
      font-size: 18px;
      color: var(--text-secondary);
      max-width: 500px;
      margin: 24px 0 32px;
    }
    .btn-primary-glow {
      background: var(--gradient-accent);
      border: none;
      border-radius: var(--radius-btn);
      padding: 12px 32px;
      color: white;
      font-weight: 600;
      transition: var(--transition-smooth);
      box-shadow: 0 4px 15px rgba(0,194,255,0.4);
    }
    .btn-primary-glow:hover {
      box-shadow: var(--shadow-glow);
      transform: translateY(-2px);
      color: white;
    }
    .btn-outline-accent {
      border: 1px solid var(--accent);
      color: var(--accent);
      background: transparent;
      border-radius: var(--radius-btn);
      padding: 12px 32px;
      font-weight: 600;
      transition: var(--transition-smooth);
    }
    .btn-outline-accent:hover {
      background: rgba(0,194,255,0.1);
      color: #33d6ff;
      border-color: #33d6ff;
    }
    .hero-image {
      border-radius: 24px;
      overflow: hidden;
      box-shadow: 0 20px 40px rgba(0,0,0,0.6);
      border: 1px solid var(--border-glass);
    }
    /* 卡片通用 */
    .glass-card {
      background: var(--card-glass);
      backdrop-filter: blur(18px);
      -webkit-backdrop-filter: blur(18px);
      border: 1px solid var(--border-glass);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      transition: var(--transition-smooth);
    }
    .glass-card:hover {
      transform: translateY(-4px);
      border-color: rgba(0,194,255,0.4);
      box-shadow: 0 12px 36px rgba(0,0,0,0.6);
    }
    .icon-box {
      width: 64px;
      height: 64px;
      background: rgba(0,194,255,0.1);
      border-radius: var(--radius-icon);
      display: flex;
      align-items: center;
      justify-content: center;
      color: var(--accent);
      font-size: 32px;
      margin-bottom: 20px;
    }
    .feature-card {
      padding: 32px 24px;
      text-align: left;
    }
    /* 场景卡片 */
    .scene-card {
      background: var(--card-glass);
      backdrop-filter: blur(18px);
      border-radius: var(--radius-card);
      border-left: 3px solid var(--accent);
      overflow: hidden;
      display: flex;
      flex-wrap: wrap;
      margin-bottom: 30px;
    }
    .scene-img {
      flex: 0 0 40%;
      min-height: 240px;
      background-size: cover;
      background-position: center;
      position: relative;
    }
    .scene-img::after {
      content: "";
      position: absolute;
      top: 0; left: 0; right: 0; bottom: 0;
      background: rgba(10,25,41,0.55);
    }
    .scene-text {
      flex: 1;
      padding: 32px;
    }
    /* 数据数字 */
    .metric-number {
      font-family: var(--font-mono);
      font-size: 42px;
      font-weight: 700;
      background: var(--gradient-accent);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
      display: inline-block;
    }
    /* FAQ */
    .faq-card {
      background: var(--card-glass);
      backdrop-filter: blur(18px);
      border: 1px solid var(--border-glass);
      border-radius: var(--radius-card);
      margin-bottom: 12px;
      cursor: pointer;
      transition: var(--transition-smooth);
    }
    .faq-question {
      padding: 20px 24px;
      font-weight: 600;
      color: var(--text-primary);
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .faq-answer {
      padding: 0 24px 20px;
      color: var(--text-secondary);
      display: none;
    }
    .faq-card.open .faq-answer {
      display: block;
    }
    .faq-card.open .bi-plus::before {
      content: "\f2ea";
    }
    /* CTA 横幅 */
    .cta-banner {
      background: #0F2438;
      padding: 60px 0;
    }
    /* 页脚 */
    .footer-links a {
      color: var(--text-secondary);
      text-decoration: none;
      display: block;
      margin-bottom: 6px;
    }
    .footer-links a:hover {
      color: var(--accent);
      text-decoration: underline;
    }
    .copyright {
      color: var(--text-muted);
      font-size: 14px;
    }
    /* 响应式 */
    @media (max-width: 992px) {
      h1 { font-size: 40px; }
      h2 { font-size: 30px; }
      .scene-card { flex-direction: column; }
      .scene-img { flex: 0 0 200px; }
    }
    @media (max-width: 576px) {
      h1 { font-size: 32px; }
      h2 { font-size: 26px; }
      .nav-chips { display: none; }
      .navbar-custom .container-custom { flex-wrap: wrap; }
      .mobile-menu-toggle { display: block; }
      .hero-section { padding: 50px 0 60px; }
    }
    .mobile-menu-toggle {
      display: none;
      background: none;
      border: none;
      color: var(--metal-light);
      font-size: 28px;
    }
    @media (max-width: 576px) {
      .mobile-menu-toggle { display: block; }
      .nav-chips.mobile-open {
        display: flex;
        flex-direction: column;
        width: 100%;
        background: rgba(10,25,41,0.95);
        padding: 15px 0;
        margin-top: 10px;
      }
    }