/* roulang page: index */
:root {
      --primary-deep: #0A2E2B;
      --primary-dark: #0B3D2E;
      --accent-signal: #00C896;
      --accent-amber: #F59E0B;
      --bg-warm: #F7F5F2;
      --card-white: #FFFFFF;
      --text-primary: #1A1A1A;
      --text-secondary: #5A5A5A;
      --text-muted: #8A8A8A;
      --border-light: #E5E7EB;
      --shadow-card: 0 2px 12px rgba(0,0,0,0.06);
      --shadow-hover: 0 8px 24px rgba(0,0,0,0.12);
      --radius-card: 12px;
      --radius-btn: 8px;
      --space-section: 100px;
      --space-element: 24px;
      --font-heading: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --font-body: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --nav-width: 240px;
      --transition-smooth: all 0.2s ease;
    }
    *, *::before, *::after {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    html {
      scroll-behavior: smooth;
      font-size: 16px;
    }
    body {
      font-family: var(--font-body);
      background-color: var(--bg-warm);
      color: var(--text-primary);
      line-height: 1.7;
      font-weight: 400;
      -webkit-font-smoothing: antialiased;
      display: flex;
      min-height: 100vh;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition-smooth);
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    button, .button {
      cursor: pointer;
      font-family: var(--font-body);
      border: none;
      background: none;
      transition: var(--transition-smooth);
    }
    input, textarea {
      font-family: var(--font-body);
      outline: none;
    }
    h1, h2, h3, h4 {
      font-family: var(--font-heading);
      font-weight: 700;
    }
    h1 {
      font-size: 3.2rem;
      letter-spacing: -0.02em;
      line-height: 1.2;
    }
    h2 {
      font-size: 2.2rem;
      letter-spacing: -0.01em;
      margin-bottom: 0.75rem;
    }
    h3 {
      font-size: 1.4rem;
      font-weight: 600;
    }
    .container-main {
      margin-left: var(--nav-width);
      width: calc(100% - var(--nav-width));
      max-width: 1200px;
      padding: 0 32px;
      margin-right: auto;
    }
    /* 左侧导航 App Shell */
    .app-nav {
      position: fixed;
      left: 0;
      top: 0;
      width: var(--nav-width);
      height: 100vh;
      background: var(--primary-deep);
      color: white;
      display: flex;
      flex-direction: column;
      justify-content: space-between;
      padding: 2rem 1.5rem;
      z-index: 100;
      box-shadow: 2px 0 12px rgba(0,0,0,0.08);
    }
    .nav-logo {
      display: flex;
      align-items: center;
      gap: 0.5rem;
      font-size: 1.5rem;
      font-weight: 700;
      letter-spacing: 0.5px;
      margin-bottom: 2.5rem;
    }
    .nav-logo i {
      color: var(--accent-signal);
      font-size: 2rem;
    }
    .nav-links {
      list-style: none;
      flex: 1;
    }
    .nav-links li {
      margin-bottom: 0.5rem;
    }
    .nav-links a {
      display: block;
      padding: 0.8rem 1rem;
      border-radius: 8px;
      color: rgba(255,255,255,0.8);
      font-weight: 500;
      transition: var(--transition-smooth);
      font-size: 1rem;
      position: relative;
    }
    .nav-links a:hover,
    .nav-links a.active {
      background: rgba(255,255,255,0.08);
      color: white;
    }
    .nav-links a.active::after {
      content: '';
      position: absolute;
      left: 0;
      bottom: 4px;
      width: 24px;
      height: 3px;
      background: var(--accent-signal);
      border-radius: 2px;
    }
    .nav-footer {
      font-size: 0.8rem;
      color: rgba(255,255,255,0.5);
      border-top: 1px solid rgba(255,255,255,0.15);
      padding-top: 1.25rem;
    }
    /* 移动端顶部导航 */
    .mobile-header {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 56px;
      background: var(--primary-deep);
      color: white;
      align-items: center;
      justify-content: space-between;
      padding: 0 1.25rem;
      z-index: 110;
      box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    }
    .mobile-logo {
      font-weight: 700;
      font-size: 1.2rem;
    }
    .hamburger {
      font-size: 1.5rem;
      background: none;
      border: none;
      color: white;
    }
    .drawer-menu {
      position: fixed;
      top: 56px;
      left: -100%;
      width: 100%;
      height: calc(100vh - 56px);
      background: var(--primary-deep);
      z-index: 105;
      transition: left 0.25s ease;
      padding: 1.5rem;
      display: flex;
      flex-direction: column;
      gap: 0.75rem;
    }
    .drawer-menu.open {
      left: 0;
    }
    .drawer-menu a {
      color: white;
      font-size: 1.1rem;
      padding: 0.75rem;
      border-radius: 8px;
      font-weight: 500;
    }
    /* 通用板块 */
    section {
      padding: var(--space-section) 0;
    }
    .btn-primary {
      background: var(--accent-signal);
      color: white;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      display: inline-block;
      text-align: center;
      min-height: 48px;
      line-height: 1.2;
    }
    .btn-primary:hover {
      background: #00A67D;
      color: white;
    }
    .btn-outline {
      border: 2px solid var(--primary-deep);
      color: var(--primary-deep);
      padding: 12px 30px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      background: transparent;
    }
    .btn-outline:hover {
      background: var(--primary-deep);
      color: white;
    }
    .card {
      background: var(--card-white);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      padding: 28px;
      transition: transform 0.2s, box-shadow 0.2s;
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    /* Hero */
    .hero {
      background: linear-gradient(135deg, #0A2E2B 0%, #0B3D2E 100%);
      color: white;
      padding: 120px 0 100px;
      position: relative;
      overflow: hidden;
    }
    .hero::before {
      content: "";
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background-image: radial-gradient(circle at 20% 30%, rgba(0,200,150,0.08) 0%, transparent 30%);
      pointer-events: none;
    }
    .hero-content {
      position: relative;
      z-index: 2;
    }
    /* 非对称网格 */
    .asymmetric-grid {
      display: grid;
      grid-template-columns: 1.2fr 0.8fr;
      gap: 24px;
    }
    .asymmetric-grid .large-card {
      grid-row: span 2;
    }
    /* 横向滚动 */
    .scroll-x {
      display: flex;
      gap: 24px;
      overflow-x: auto;
      padding-bottom: 16px;
      scrollbar-width: thin;
    }
    .scroll-x::-webkit-scrollbar {
      height: 6px;
    }
    .scroll-x::-webkit-scrollbar-thumb {
      background: #ccc;
      border-radius: 6px;
    }
    .product-card {
      min-width: 260px;
      flex: 0 0 auto;
      background: white;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      overflow: hidden;
    }
    .tag {
      background: #E0F2E9;
      color: #0B3D2E;
      padding: 4px 12px;
      border-radius: 20px;
      font-size: 0.75rem;
      font-weight: 600;
    }
    .stat-number {
      font-size: 2.8rem;
      font-weight: 700;
      color: var(--accent-signal);
      line-height: 1.1;
    }
    .faq-item {
      border-bottom: 1px solid var(--border-light);
    }
    .faq-title {
      background: none;
      border: none;
      width: 100%;
      text-align: left;
      padding: 18px 0;
      font-weight: 600;
      font-size: 1.1rem;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .faq-content {
      padding: 0 0 20px;
      color: var(--text-secondary);
    }
    footer {
      background: var(--primary-deep);
      color: white;
      padding: 60px 0 30px;
    }
    @media (max-width: 1024px) {
      .app-nav {
        display: none;
      }
      .mobile-header {
        display: flex;
      }
      .container-main {
        margin-left: 0;
        width: 100%;
        padding: 0 20px;
        margin-top: 56px;
      }
      h1 {
        font-size: 2.4rem;
      }
      h2 {
        font-size: 1.9rem;
      }
    }
    @media (max-width: 640px) {
      .asymmetric-grid {
        grid-template-columns: 1fr;
      }
      .hero {
        padding: 80px 0 60px;
      }
      h1 {
        font-size: 2rem;
      }
      .stat-number {
        font-size: 2.2rem;
      }
    }