/* roulang page: index */
/* ----- CSS 设计变量 & 全局重置 ----- */
    :root {
      --primary-deep: #0A1628;
      --primary-card: #112240;
      --accent-cyan: #00E5FF;
      --cta-orange: #FF6B35;
      --success-green: #00C9A7;
      --text-white: #F0F4F8;
      --text-muted: #8899AA;
      --glass-bg: rgba(17, 34, 64, 0.7);
      --glass-border: rgba(0, 229, 255, 0.15);
      --shadow-card: 0 8px 32px rgba(0, 0, 0, 0.4);
      --radius-card: 16px;
      --radius-btn: 8px;
      --radius-data: 12px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
      --font-mono: "Inter", "SF Pro Display", system-ui, sans-serif;
      --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    }

    * {
      box-sizing: border-box;
    }

    body {
      margin: 0;
      font-family: var(--font-sans);
      background-color: var(--primary-deep);
      color: var(--text-white);
      line-height: 1.7;
      overflow-x: hidden;
    }

    .container-main {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.5rem;
      padding-right: 1.5rem;
    }

    /* 玻璃拟态卡片基类 */
    .glass-card {
      background: var(--glass-bg);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border: 1px solid var(--glass-border);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
    }

    /* 按钮系统 */
    .btn-primary {
      background-color: var(--accent-cyan);
      color: #0A1628;
      font-weight: 700;
      padding: 0.75rem 2rem;
      border-radius: var(--radius-btn);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 0.5rem;
      transition: var(--transition-smooth);
      box-shadow: 0 0 20px rgba(0, 229, 255, 0.5);
      border: none;
      cursor: pointer;
      text-decoration: none;
      font-size: 1rem;
    }
    .btn-primary:hover {
      box-shadow: 0 0 35px rgba(0, 229, 255, 0.8);
      transform: translateY(-2px);
      color: #0A1628;
    }

    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--accent-cyan);
      color: var(--accent-cyan);
      font-weight: 600;
      padding: 0.75rem 2rem;
      border-radius: var(--radius-btn);
      transition: var(--transition-smooth);
      display: inline-flex;
      align-items: center;
      gap: 0.5rem;
      cursor: pointer;
      text-decoration: none;
    }
    .btn-outline:hover {
      background: rgba(0, 229, 255, 0.1);
      box-shadow: 0 0 15px rgba(0, 229, 255, 0.3);
      transform: translateY(-2px);
    }

    .btn-cta-orange {
      background: var(--cta-orange);
      color: #fff;
      font-weight: 700;
      padding: 0.9rem 2.5rem;
      border-radius: var(--radius-btn);
      box-shadow: 0 0 25px rgba(255, 107, 53, 0.6);
      transition: var(--transition-smooth);
      border: none;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      gap: 0.5rem;
      text-decoration: none;
    }
    .btn-cta-orange:hover {
      box-shadow: 0 0 40px rgba(255, 107, 53, 0.9);
      transform: scale(1.03);
      color: #fff;
    }

    /* 导航栏 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 50;
      background: transparent;
      transition: background 0.4s ease, backdrop-filter 0.4s ease;
      padding: 0.75rem 0;
    }
    .site-header.scrolled {
      background: rgba(10, 22, 40, 0.85);
      backdrop-filter: blur(16px);
      -webkit-backdrop-filter: blur(16px);
      border-bottom: 1px solid rgba(0, 229, 255, 0.2);
    }
    .nav-link {
      color: var(--text-white);
      font-weight: 500;
      transition: color 0.2s;
      position: relative;
      text-decoration: none;
    }
    .nav-link:hover {
      color: var(--accent-cyan);
    }
    .nav-link::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--accent-cyan);
      transition: width 0.25s ease;
    }
    .nav-link:hover::after {
      width: 100%;
    }

    /* 移动端菜单 */
    .mobile-menu {
      display: none;
    }
    @media (max-width: 767px) {
      .desktop-nav {
        display: none;
      }
      .mobile-menu-btn {
        display: block;
      }
    }

    /* Hero 动态背景 */
    .hero-graphic {
      background: radial-gradient(circle at 30% 40%, rgba(0,229,255,0.15) 0%, transparent 60%),
                  repeating-linear-gradient(45deg, rgba(0,229,255,0.05) 0px, rgba(0,229,255,0.05) 2px, transparent 2px, transparent 8px);
    }

    /* 数据数字动画 */
    .data-number {
      font-family: var(--font-mono);
      font-weight: 800;
      color: var(--accent-cyan);
      text-shadow: 0 0 8px rgba(0,229,255,0.4);
    }

    /* FAQ 手风琴 */
    .faq-item {
      border-bottom: 1px solid rgba(0,229,255,0.15);
    }
    .faq-question {
      cursor: pointer;
      font-weight: 700;
      color: var(--text-white);
      display: flex;
      align-items: center;
      gap: 0.75rem;
      transition: color 0.2s;
    }
    .faq-question:hover {
      color: var(--accent-cyan);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: var(--text-muted);
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
    }

    /* 解决方案对比连接线 */
    .comparison-line {
      position: relative;
    }
    .comparison-line::before {
      content: '';
      position: absolute;
      left: 50%;
      top: 0;
      bottom: 0;
      width: 2px;
      background: linear-gradient(to bottom, var(--accent-cyan), transparent);
    }

    footer a {
      color: var(--text-muted);
      text-decoration: none;
      transition: color 0.2s;
    }
    footer a:hover {
      color: var(--accent-cyan);
    }

    /* 移动端底部悬浮CTA */
    .mobile-bottom-cta {
      display: none;
    }
    @media (max-width: 767px) {
      .mobile-bottom-cta {
        display: flex;
        position: fixed;
        bottom: 20px;
        left: 20px;
        right: 20px;
        z-index: 45;
        justify-content: center;
      }
    }

@keyframes spin-slow {
      from { transform: rotate(0deg); }
      to { transform: rotate(360deg); }
    }
    .animate-spin-slow {
      animation: spin-slow 12s linear infinite;
    }
    /* 额外响应式微调 */
    @media (max-width: 640px) {
      .glass-card {
        padding: 1.5rem;
      }
      .btn-primary, .btn-outline {
        padding: 0.6rem 1.5rem;
        font-size: 0.9rem;
      }
    }