/* roulang page: index */
/* ===== 设计变量与重置 ===== */
    :root {
      --primary-deep: #1E2A38;
      --accent-orange: #FF6B2B;
      --accent-hover: #E55A1F;
      --bg-light: #F8F9FA;
      --white: #FFFFFF;
      --text-dark: #4A4A4A;
      --text-muted: #8C8C8C;
      --border-light: #E6E9ED;
      --shadow-card: 0 4px 20px rgba(0,0,0,0.06);
      --shadow-hover: 0 12px 28px rgba(0,0,0,0.12);
      --radius-md: 12px;
      --radius-pill: 30px;
      --transition: all 0.25s ease;
      --nav-height: 72px;
    }
    * {
      box-sizing: border-box;
    }
    body {
      font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      background-color: var(--bg-light);
      color: var(--text-dark);
      line-height: 1.6;
      margin: 0;
      padding-top: var(--nav-height);
    }
    h1, h2, h3, h4 {
      font-weight: 700;
      color: var(--primary-deep);
      margin-bottom: 0.75rem;
    }
    h1 { font-size: 48px; }
    h2 { font-size: 36px; }
    h3 { font-size: 24px; font-weight: 600; }
    p, li { font-size: 16px; color: var(--text-dark); }
    .text-muted { color: var(--text-muted); font-size: 14px; }
    a { color: inherit; text-decoration: none; }
    img { max-width: 100%; height: auto; display: block; }
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 20px;
    }
    .section-padding {
      padding: 80px 0;
    }
    /* 按钮体系 */
    .btn {
      display: inline-block;
      font-weight: 600;
      border-radius: var(--radius-pill);
      padding: 12px 28px;
      transition: var(--transition);
      text-align: center;
      cursor: pointer;
      border: 2px solid transparent;
      font-size: 16px;
    }
    .btn-primary {
      background: var(--accent-orange);
      color: white;
      border-color: var(--accent-orange);
    }
    .btn-primary:hover {
      background: var(--accent-hover);
      border-color: var(--accent-hover);
      color: white;
    }
    .btn-outline {
      background: transparent;
      color: var(--primary-deep);
      border-color: var(--primary-deep);
    }
    .btn-outline:hover {
      background: var(--primary-deep);
      color: white;
    }
    /* 卡片基础 */
    .card {
      background: var(--white);
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-card);
      transition: var(--transition);
      overflow: hidden;
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    /* 导航 */
    .top-nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--nav-height);
      background: rgba(255,255,255,0.96);
      backdrop-filter: blur(8px);
      box-shadow: 0 2px 12px rgba(0,0,0,0.04);
      z-index: 100;
      display: flex;
      align-items: center;
    }
    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 20px;
    }
    .brand {
      font-size: 24px;
      font-weight: 700;
      color: var(--primary-deep);
      letter-spacing: 1px;
    }
    .nav-links {
      display: flex;
      gap: 28px;
      align-items: center;
    }
    .nav-links a {
      font-weight: 500;
      color: var(--text-dark);
      transition: color 0.2s;
      font-size: 15px;
    }
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--accent-orange);
    }
    .nav-cta {
      background: var(--accent-orange);
      color: white !important;
      padding: 8px 22px;
      border-radius: 20px;
      font-weight: 600;
    }
    .hamburger {
      display: none;
      font-size: 24px;
      cursor: pointer;
      color: var(--primary-deep);
    }
    /* 移动端导航面板 */
    .mobile-menu {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: var(--bg-light);
      z-index: 200;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 32px;
      transform: translateX(100%);
      transition: transform 0.3s ease;
    }
    .mobile-menu.open {
      transform: translateX(0);
    }
    .mobile-menu a {
      font-size: 22px;
      font-weight: 600;
      color: var(--primary-deep);
    }
    .close-menu {
      position: absolute;
      top: 24px;
      right: 24px;
      font-size: 32px;
      cursor: pointer;
    }
    /* Hero */
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 48px;
    }
    .hero-left { flex: 0 0 55%; }
    .hero-right {
      flex: 0 0 45%;
      position: relative;
    }
    .hero-image {
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-card);
      width: 100%;
      object-fit: cover;
    }
    .hero-actions {
      display: flex;
      gap: 16px;
      margin-top: 28px;
    }
    /* 亮点网格 */
    .highlight-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }
    .icon-circle {
      font-size: 36px;
      color: var(--accent-orange);
      margin-bottom: 16px;
      transition: transform 0.2s;
    }
    .card:hover .icon-circle {
      transform: scale(1.1);
    }
    /* 案例瀑布 */
    .case-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 24px;
    }
    .case-item {
      border-radius: var(--radius-md);
      overflow: hidden;
      background: white;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
    }
    .case-item:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .case-img {
      width: 100%;
      height: 220px;
      object-fit: cover;
    }
    .case-tag {
      color: var(--accent-orange);
      font-weight: 600;
      font-size: 14px;
    }
    /* 对比表 */
    .compare-table {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 0;
      border-radius: var(--radius-md);
      overflow: hidden;
      box-shadow: var(--shadow-card);
    }
    .col-traditional {
      background: #f2f3f5;
      padding: 32px;
    }
    .col-letou {
      background: white;
      padding: 32px;
      border-left: 1px solid var(--border-light);
    }
    .highlight-row {
      background: #FFF5F0;
      padding: 12px 16px;
      border-radius: 8px;
      margin: 8px 0;
    }
    /* 信任带 */
    .trust-strip {
      display: flex;
      gap: 40px;
      overflow-x: auto;
      padding: 24px 0;
      align-items: center;
      justify-content: center;
    }
    .stat-item {
      text-align: center;
      min-width: 120px;
    }
    .stat-number {
      font-size: 40px;
      font-weight: 700;
      color: var(--accent-orange);
    }
    /* FAQ */
    .accordion-item {
      border-bottom: 1px solid var(--border-light);
      padding: 18px 0;
    }
    .accordion-question {
      font-weight: 600;
      font-size: 18px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      color: var(--primary-deep);
    }
    .accordion-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      background: #f9f9fb;
      border-radius: 8px;
      margin-top: 8px;
      padding: 0 16px;
      color: var(--text-dark);
    }
    .accordion-answer.open {
      max-height: 200px;
      padding: 16px;
    }
    /* CTA 横幅 */
    .cta-banner {
      background: var(--primary-deep);
      border-radius: var(--radius-md);
      padding: 60px 40px;
      text-align: center;
    }
    .cta-banner h2 {
      color: white;
    }
    /* 页脚 */
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
      color: rgba(255,255,255,0.8);
    }
    .social-icons i {
      font-size: 22px;
      margin-right: 16px;
      transition: color 0.2s;
    }
    .social-icons i:hover {
      color: var(--accent-orange);
    }
    /* 响应式 */
    @media (max-width: 1024px) {
      h1 { font-size: 38px; }
      .hero-grid { flex-direction: column; }
      .hero-left, .hero-right { flex: 1 1 auto; }
      .highlight-grid { grid-template-columns: repeat(2,1fr); }
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: block; }
      .highlight-grid { grid-template-columns: 1fr; }
      .case-grid { grid-template-columns: 1fr; }
      .compare-table { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
      .section-padding { padding: 60px 0; }
    }
    @media (max-width: 520px) {
      .footer-grid { grid-template-columns: 1fr; }
      .trust-strip { justify-content: flex-start; }
    }