/* roulang page: index */
/* 设计变量与全局重置 */
    :root {
      --primary: #1A5F7A;
      --primary-light: #0EA5E9;
      --accent: #F59E0B;
      --bg-light: #F8FAFC;
      --card-bg: #FFFFFF;
      --dark-bg: #0F172A;
      --text-main: #1E293B;
      --text-muted: #64748B;
      --border-light: #E2E8F0;
      --radius-sm: 8px;
      --radius-md: 12px;
      --radius-lg: 16px;
      --shadow-card: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
      --shadow-hover: 0 10px 25px rgba(0,0,0,0.08);
      --transition: all 0.3s ease;
    }
    * {
      box-sizing: border-box;
    }
    body {
      margin: 0;
      font-family: 'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
      background-color: var(--bg-light);
      color: var(--text-main);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }
    .container-custom {
      max-width: 1200px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.5rem;
      padding-right: 1.5rem;
    }
    /* 导航样式 */
    .nav-blur {
      background-color: rgba(255,255,255,0.85);
      backdrop-filter: blur(10px);
      border-bottom: 1px solid var(--border-light);
    }
    .logo-text {
      font-weight: 700;
      font-size: 1.5rem;
      letter-spacing: -0.3px;
      color: var(--primary);
    }
    .nav-link {
      color: #475569;
      transition: color 0.2s;
      font-weight: 500;
    }
    .nav-link:hover {
      color: var(--primary);
    }
    .btn-primary {
      background-color: var(--primary);
      color: white;
      border-radius: var(--radius-sm);
      padding: 0.6rem 1.5rem;
      font-weight: 600;
      transition: background-color 0.2s, transform 0.1s;
      border: none;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      justify-content: center;
    }
    .btn-primary:hover {
      background-color: #154E66;
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--primary);
      color: var(--primary);
      border-radius: var(--radius-sm);
      padding: 0.6rem 1.5rem;
      font-weight: 600;
      transition: all 0.2s;
      cursor: pointer;
    }
    .btn-outline:hover {
      background-color: rgba(26,95,122,0.08);
    }
    .btn-accent {
      background-color: var(--accent);
      color: #0F172A;
      border-radius: var(--radius-sm);
      padding: 0.7rem 2rem;
      font-weight: 700;
      border: none;
      cursor: pointer;
      transition: background-color 0.2s, box-shadow 0.2s;
      box-shadow: 0 4px 10px rgba(245,158,11,0.3);
    }
    .btn-accent:hover {
      background-color: #D98A0B;
      box-shadow: 0 6px 15px rgba(245,158,11,0.45);
    }
    /* 卡片与交互 */
    .card {
      background: var(--card-bg);
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-card);
      transition: var(--transition);
      border: 1px solid rgba(0,0,0,0.02);
    }
    .card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
      border-color: rgba(14,165,233,0.18);
    }
    .pain-card {
      background: #F9FAFB;
      border-left: 4px solid #EF4444;
      border-radius: var(--radius-md);
      transition: var(--transition);
    }
    .pain-card:hover {
      background: #FEF2F2;
      border-left-color: #DC2626;
    }
    /* 数据数字样式 */
    .stat-number {
      font-size: 3.5rem;
      font-weight: 800;
      color: var(--primary);
      line-height: 1.1;
    }
    /* FAQ 手风琴模拟 */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
    }
    .faq-question {
      cursor: pointer;
      font-weight: 600;
      padding: 1.2rem 0;
      display: flex;
      justify-content: space-between;
      align-items: center;
      color: var(--text-main);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease, padding 0.3s ease;
      color: #475569;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-bottom: 1.2rem;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }
    .faq-icon {
      transition: transform 0.3s;
      font-size: 1.3rem;
      color: var(--primary-light);
    }
    /* 装饰信号波 */
    .signal-wave {
      display: inline-block;
      width: 8px;
      height: 20px;
      background: var(--primary-light);
      margin: 0 2px;
      border-radius: 4px;
      animation: wave 0.9s infinite ease-in-out alternate;
    }
    .signal-wave:nth-child(2) { animation-delay: 0.1s; height: 28px; }
    .signal-wave:nth-child(3) { animation-delay: 0.2s; height: 16px; }
    @keyframes wave {
      0% { transform: scaleY(0.6); opacity: 0.7; }
      100% { transform: scaleY(1); opacity: 1; }
    }
    /* 移动端菜单 */
    .mobile-menu {
      display: none;
      flex-direction: column;
      background: white;
      position: absolute;
      top: 65px;
      left: 0;
      width: 100%;
      box-shadow: 0 10px 20px rgba(0,0,0,0.05);
      padding: 1rem 1.5rem;
      border-bottom: 1px solid var(--border-light);
    }
    @media (max-width: 768px) {
      .desktop-nav { display: none; }
      .hamburger-btn { display: block; }
      .mobile-menu.show { display: flex; }
      .stat-number { font-size: 2.8rem; }
    }
    @media (min-width: 769px) {
      .hamburger-btn { display: none; }
    }
    /* 占位图片背景 */
    .hero-bg {
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
    }
    .solution-img {
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-card);
      object-fit: cover;
      width: 100%;
      height: auto;
    }