/* roulang page: index */
:root {
      --deep-ocean: #0B1E36;
      --whale-white: #F4F6F9;
      --coral-orange: #FF6B4A;
      --phosphor-cyan: #00C9A7;
      --text-dark: #1A1A2E;
      --text-secondary: #5C6B7A;
      --text-light: #B0C4DE;
      --shadow-sm: 0 4px 20px rgba(11,30,54,0.08);
      --shadow-hover: 0 12px 32px rgba(11,30,54,0.15);
      --radius-card: 16px;
      --radius-btn: 12px;
      --radius-badge: 8px;
      --transition-smooth: 0.3s ease;
    }

    * {
      box-sizing: border-box;
    }

    body {
      font-family: 'PingFang SC', 'Microsoft YaHei', 'Hiragino Sans GB', 'Inter', 'Roboto', sans-serif;
      margin: 0;
      background-color: var(--whale-white);
      color: var(--text-dark);
      line-height: 1.7;
      scroll-behavior: smooth;
    }

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

    /* 导航 */
    .navbar {
      position: sticky;
      top: 0;
      z-index: 50;
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(12px);
      height: 72px;
      display: flex;
      align-items: center;
      border-bottom: 1px solid rgba(0,0,0,0.04);
      transition: background 0.3s;
    }
    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 8px;
      font-weight: 700;
      font-size: 1.5rem;
      color: var(--deep-ocean);
      text-decoration: none;
      letter-spacing: -0.3px;
    }
    .logo i {
      color: var(--phosphor-cyan);
      font-size: 1.8rem;
    }
    .nav-links {
      display: flex;
      gap: 2rem;
      align-items: center;
    }
    .nav-link {
      text-decoration: none;
      color: var(--text-dark);
      font-weight: 500;
      font-size: 0.95rem;
      position: relative;
      padding-bottom: 4px;
      transition: color 0.2s;
    }
    .nav-link:hover,
    .nav-link.active {
      color: var(--coral-orange);
    }
    .nav-link.active::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 20%;
      width: 60%;
      height: 3px;
      background: var(--coral-orange);
      border-radius: 2px;
    }
    .btn-primary-nav {
      background: var(--coral-orange);
      color: white;
      padding: 0.6rem 1.5rem;
      border-radius: var(--radius-btn);
      font-weight: 600;
      text-decoration: none;
      transition: 0.25s ease;
      border: none;
      cursor: pointer;
      font-size: 0.95rem;
    }
    .btn-primary-nav:hover {
      background: #E85A3A;
      transform: scale(1.02);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
    }
    .hamburger span {
      width: 26px;
      height: 3px;
      background: var(--coral-orange);
      border-radius: 4px;
      transition: 0.2s;
    }
    .mobile-menu {
      display: none;
      position: fixed;
      top: 72px;
      left: 0;
      width: 100%;
      background: var(--deep-ocean);
      padding: 2rem 1.5rem;
      flex-direction: column;
      gap: 1.5rem;
      z-index: 45;
    }
    .mobile-menu a {
      color: white;
      font-size: 1.25rem;
      text-decoration: none;
      font-weight: 500;
      border-bottom: 1px solid rgba(255,255,255,0.15);
      padding-bottom: 0.5rem;
    }

    /* 卡片与组件 */
    .card {
      background: white;
      border-radius: var(--radius-card);
      padding: 2rem;
      box-shadow: var(--shadow-sm);
      transition: var(--transition-smooth);
    }
    .card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-hover);
    }
    .stat-badge {
      font-size: 2.5rem;
      font-weight: 800;
      color: var(--phosphor-cyan);
      line-height: 1.2;
      margin-bottom: 0.5rem;
    }
    .btn-main {
      background: var(--coral-orange);
      color: white;
      font-weight: 600;
      padding: 0.9rem 2rem;
      border-radius: var(--radius-btn);
      text-decoration: none;
      display: inline-block;
      transition: 0.25s ease;
      border: none;
      cursor: pointer;
    }
    .btn-main:hover {
      background: #E85A3A;
      transform: scale(1.02);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--deep-ocean);
      color: var(--deep-ocean);
      font-weight: 600;
      padding: 0.8rem 1.8rem;
      border-radius: var(--radius-btn);
      text-decoration: none;
      transition: 0.25s;
    }
    .btn-outline:hover {
      background: var(--deep-ocean);
      color: white;
    }
    .pricing-highlight {
      border: 2px solid var(--coral-orange);
      background: #fff9f7;
    }
    .badge-popular {
      background: var(--coral-orange);
      color: white;
      font-size: 0.8rem;
      font-weight: 600;
      padding: 0.25rem 0.8rem;
      border-radius: 20px;
      position: absolute;
      top: -12px;
      right: 20px;
    }

    /* FAQ 手风琴 */
    .faq-item {
      border-bottom: 1px solid #e2e8f0;
    }
    .faq-question {
      width: 100%;
      text-align: left;
      background: none;
      border: none;
      font-weight: 600;
      font-size: 1.1rem;
      padding: 1.2rem 0;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      color: var(--text-dark);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      background: #f8fafc;
      border-radius: 8px;
      margin-bottom: 0.5rem;
    }
    .faq-answer.open {
      max-height: 200px;
      padding: 1rem;
    }

    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .mobile-menu.active { display: flex; }
      .container { padding-left: 1rem; padding-right: 1rem; }
      h1 { font-size: 2rem !important; }
    }