/* roulang page: index */
:root {
      --primary-deep: #0A0F1E;
      --accent-red: #E94E3C;
      --accent-teal: #00C9A7;
      --bg-light: #F7F8FA;
      --text-main: #1A1D26;
      --text-secondary: #5A5F6E;
      --text-on-dark: #FFFFFF;
      --text-muted-dark: #B0B5C0;
      --card-bg: #FFFFFF;
      --border-light: #E2E5EC;
      --shadow-sm: 0 2px 12px rgba(10, 15, 30, 0.06);
      --shadow-md: 0 8px 24px rgba(10, 15, 30, 0.10);
      --radius-card: 12px;
      --radius-btn: 8px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --transition: 0.25s ease;
    }

    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }

    body {
      font-family: var(--font-sans);
      background-color: var(--bg-light);
      color: var(--text-main);
      line-height: 1.7;
      font-size: 16px;
      font-weight: 400;
    }

    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }

    h1, h2, h3 {
      font-weight: 700;
    }

    h1 {
      font-size: 48px;
      line-height: 1.2;
    }

    h2 {
      font-size: 36px;
      line-height: 1.3;
    }

    h3 {
      font-size: 22px;
      line-height: 1.4;
      font-weight: 600;
    }

    a {
      text-decoration: none;
      color: inherit;
    }

    img {
      max-width: 100%;
      height: auto;
      display: block;
    }

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      transition: var(--transition);
    }

    /* 导航 Header */
    #header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 72px;
      background: rgba(255, 255, 255, 0.95);
      backdrop-filter: blur(8px);
      box-shadow: 0 1px 8px rgba(0,0,0,0.03);
      z-index: 100;
      display: flex;
      align-items: center;
    }

    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }

    .logo {
      font-size: 24px;
      font-weight: 700;
      color: var(--primary-deep);
      letter-spacing: 1px;
    }
    .logo span {
      color: var(--accent-red);
    }

    .nav-menu {
      display: flex;
      gap: 28px;
      list-style: none;
    }
    .nav-menu a {
      font-weight: 500;
      color: var(--text-main);
      padding: 8px 0;
      border-bottom: 2px solid transparent;
      transition: var(--transition);
    }
    .nav-menu a:hover,
    .nav-menu a.active {
      color: var(--accent-red);
      border-bottom-color: var(--accent-red);
    }

    .nav-cta {
      background: var(--accent-red);
      color: white;
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      border: none;
      transition: var(--transition);
    }
    .nav-cta:hover {
      filter: brightness(0.9);
      transform: scale(1.03);
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: none;
      border: none;
    }
    .hamburger span {
      display: block;
      width: 26px;
      height: 2px;
      background: var(--primary-deep);
      border-radius: 2px;
    }

    /* Hero */
    #hero {
      background: linear-gradient(135deg, #0A0F1E 0%, #141B2D 100%);
      padding: 120px 0 80px;
      margin-top: 72px;
      color: white;
      position: relative;
      overflow: hidden;
    }

    .hero-grid {
      display: flex;
      align-items: center;
      gap: 60px;
    }
    .hero-text {
      flex: 1;
    }
    .hero-text h1 {
      margin-bottom: 20px;
      animation: fadeUp 0.7s ease;
    }
    .hero-sub {
      font-size: 18px;
      color: #B0B5C0;
      margin-bottom: 36px;
      max-width: 500px;
    }
    .hero-btns {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--accent-red);
      color: white;
      padding: 14px 36px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      border: none;
      font-size: 16px;
    }
    .btn-primary:hover {
      filter: brightness(0.9);
      transform: scale(1.03);
    }
    .btn-outline-light {
      background: transparent;
      border: 2px solid white;
      color: white;
      padding: 14px 36px;
      border-radius: var(--radius-btn);
      font-weight: 600;
    }
    .btn-outline-light:hover {
      background: white;
      color: var(--primary-deep);
    }
    .hero-image {
      flex: 1;
      text-align: right;
    }
    .hero-image img {
      border-radius: 24px;
      box-shadow: 0 20px 40px rgba(0,0,0,0.5);
    }

    @keyframes fadeUp {
      0% { opacity: 0; transform: translateY(20px); }
      100% { opacity: 1; transform: translateY(0); }
    }

    /* 通用章节 */
    section {
      padding: 90px 0;
    }
    .section-title {
      text-align: center;
      margin-bottom: 56px;
    }
    .section-title h2 {
      margin-bottom: 12px;
    }
    .section-title p {
      color: var(--text-secondary);
      font-size: 18px;
    }

    /* 功能卡片网格 */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 28px;
    }
    .feature-card {
      background: var(--card-bg);
      padding: 28px 20px;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
    }
    .feature-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-md);
    }
    .feature-icon {
      width: 48px;
      height: 48px;
      background: rgba(233, 78, 60, 0.1);
      border-radius: 12px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
      color: var(--accent-red);
      font-size: 24px;
    }
    .feature-card h3 {
      margin-bottom: 12px;
    }
    .feature-card p {
      color: var(--text-secondary);
    }

    /* 场景区 */
    .scenario-row {
      display: flex;
      gap: 28px;
    }
    .scenario-item {
      flex: 1;
      background: var(--card-bg);
      border-radius: 16px;
      overflow: hidden;
      box-shadow: var(--shadow-sm);
    }
    .scenario-item img {
      width: 100%;
      height: 210px;
      object-fit: cover;
    }
    .scenario-content {
      padding: 20px;
    }

    /* 案例数据 */
    .cases-stats {
      display: flex;
      justify-content: space-around;
      flex-wrap: wrap;
      gap: 30px;
    }
    .stat-item {
      text-align: center;
    }
    .stat-number {
      font-size: 44px;
      font-weight: 700;
      color: var(--accent-teal);
      line-height: 1.2;
    }
    .stat-label {
      color: var(--text-secondary);
    }

    /* 价格卡片 */
    .pricing-grid {
      display: flex;
      align-items: stretch;
      gap: 28px;
      justify-content: center;
    }
    .pricing-card {
      background: white;
      border-radius: var(--radius-card);
      padding: 32px;
      flex: 1;
      box-shadow: var(--shadow-sm);
      border: 2px solid transparent;
      transition: var(--transition);
    }
    .pricing-card.featured {
      border-color: var(--accent-red);
      transform: scale(1.02);
      background: var(--primary-deep);
      color: white;
    }
    .pricing-card h3 {
      margin-bottom: 16px;
    }
    .price {
      font-size: 40px;
      font-weight: 700;
      margin: 20px 0;
    }
    .btn-outline {
      border: 2px solid var(--primary-deep);
      background: transparent;
      padding: 12px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      width: 100%;
      margin-top: 24px;
    }
    .featured .btn-outline {
      border-color: white;
      color: white;
    }
    .featured .btn-outline:hover {
      background: white;
      color: var(--primary-deep);
    }

    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid var(--border-light);
    }
    .faq-question {
      background: none;
      border: none;
      width: 100%;
      text-align: left;
      padding: 20px 0;
      font-size: 18px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      color: var(--text-main);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-secondary);
      padding: 0 0;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      padding-bottom: 20px;
    }

    /* CTA尾屏 */
    #cta {
      background: var(--primary-deep);
      color: white;
      text-align: center;
      padding: 80px 0;
    }

    /* Footer */
    #footer {
      background: #0A0F1E;
      color: var(--text-muted-dark);
      padding: 50px 0 30px;
    }
    .footer-grid {
      display: flex;
      justify-content: space-between;
      flex-wrap: wrap;
      gap: 30px;
      margin-bottom: 40px;
    }
    .footer-links a {
      display: block;
      margin-bottom: 8px;
      color: var(--text-muted-dark);
    }
    .copyright {
      border-top: 1px solid #2a2f3a;
      padding-top: 20px;
      text-align: center;
      font-size: 14px;
    }

    /* 移动端菜单 */
    .mobile-menu {
      display: none;
      position: fixed;
      top: 72px;
      left: 0;
      width: 100%;
      background: rgba(10,15,30,0.96);
      backdrop-filter: blur(12px);
      padding: 30px;
      flex-direction: column;
      gap: 28px;
      z-index: 99;
    }
    .mobile-menu a {
      color: white;
      font-size: 20px;
      font-weight: 500;
      border-bottom: 1px solid rgba(255,255,255,0.2);
      padding-bottom: 8px;
    }

    @media (max-width: 1024px) {
      .features-grid { grid-template-columns: repeat(2, 1fr); }
    }
    @media (max-width: 768px) {
      h1 { font-size: 32px; }
      h2 { font-size: 26px; }
      .nav-menu { display: none; }
      .nav-cta.desktop { display: none; }
      .hamburger { display: flex; }
      .hero-grid { flex-direction: column; }
      .hero-image { text-align: center; }
      .features-grid { grid-template-columns: 1fr; }
      .scenario-row { flex-direction: column; }
      .pricing-grid { flex-direction: column; }
      .pricing-card.featured { transform: none; }
    }