/* roulang page: index */
:root {
      --primary: #0AE08C;
      --primary-dark: #07b372;
      --secondary: #1B1F2E;
      --bg-page: #FAFBFC;
      --bg-card: #FFFFFF;
      --bg-light: #F9FAFB;
      --bg-footer: #F3F4F6;
      --text-heading: #111827;
      --text-body: #374151;
      --text-muted: #6B7280;
      --text-white: #FFFFFF;
      --border-light: #E5E7EB;
      --border-input: #D1D5DB;
      --success: #10B981;
      --warning: #F59E0B;
      --shadow-nav: 0 2px 8px rgba(0,0,0,0.04);
      --shadow-card-hover: 0 8px 24px rgba(0,0,0,0.08);
      --shadow-btn-hover: 0 4px 12px rgba(10,224,140,0.3);
      --radius-sm: 8px;
      --radius-md: 12px;
      --radius-lg: 16px;
      --radius-full: 999px;
      --container-max: 1280px;
      --space-section: 100px;
      --space-mobile: 60px;
      --transition: 0.2s ease;
    }

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

    body {
      font-family: 'Inter', 'PingFang SC', 'Microsoft YaHei', 'Hiragino Sans GB', sans-serif;
      background-color: var(--bg-page);
      color: var(--text-body);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

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

    a {
      text-decoration: none;
      color: inherit;
      transition: color var(--transition);
    }

    button, input {
      font-family: inherit;
    }

    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }

    /* 导航 */
    .nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 64px;
      background: #FFFFFF;
      box-shadow: var(--shadow-nav);
      border-bottom: 1px solid var(--border-light);
      display: flex;
      align-items: center;
      z-index: 50;
    }

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

    .logo {
      display: flex;
      align-items: center;
      gap: 8px;
      font-weight: 600;
      font-size: 20px;
      color: var(--text-heading);
      white-space: nowrap;
    }

    .logo svg {
      width: 28px;
      height: 28px;
      fill: var(--primary);
    }

    .nav-links {
      display: flex;
      gap: 28px;
      align-items: center;
      list-style: none;
    }

    .nav-links a {
      color: #4B5563;
      font-weight: 500;
      font-size: 15px;
      padding-bottom: 4px;
      border-bottom: 2px solid transparent;
      transition: all var(--transition);
    }

    .nav-links a:hover,
    .nav-links a.active {
      color: var(--primary);
      border-bottom-color: var(--primary);
    }

    .nav-right {
      display: flex;
      align-items: center;
      gap: 12px;
    }

    .search-box {
      display: flex;
      align-items: center;
      background: #F3F4F6;
      border-radius: var(--radius-full);
      padding: 8px 16px;
      gap: 8px;
      border: 1px solid transparent;
      transition: border var(--transition);
    }

    .search-box input {
      border: none;
      background: transparent;
      outline: none;
      font-size: 14px;
      width: 140px;
      color: var(--text-body);
    }

    .search-box input::placeholder {
      color: #9CA3AF;
    }

    .search-box:focus-within {
      border-color: var(--primary);
      background: #FFFFFF;
    }

    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 10px 20px;
      border-radius: var(--radius-sm);
      font-weight: 500;
      font-size: 15px;
      transition: all var(--transition);
      cursor: pointer;
      border: none;
      white-space: nowrap;
    }

    .btn-primary {
      background: var(--primary);
      color: var(--text-white);
      box-shadow: 0 2px 6px rgba(10,224,140,0.2);
    }

    .btn-primary:hover {
      background: #08c97a;
      transform: scale(1.02);
      box-shadow: var(--shadow-btn-hover);
    }

    .btn-secondary {
      background: transparent;
      border: 1.5px solid var(--primary);
      color: var(--primary);
    }

    .btn-secondary:hover {
      background: rgba(10,224,140,0.05);
    }

    .btn-white {
      background: #FFFFFF;
      color: var(--secondary);
    }

    .btn-white:hover {
      opacity: 0.9;
    }

    .btn-outline-white {
      background: transparent;
      border: 1.5px solid #FFFFFF;
      color: #FFFFFF;
    }

    .btn-outline-white:hover {
      background: rgba(255,255,255,0.1);
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: none;
      border: none;
    }

    .hamburger span {
      width: 22px;
      height: 2px;
      background: var(--text-heading);
      transition: var(--transition);
    }

    @media (max-width: 1024px) {
      .nav-links {
        display: none;
      }
      .hamburger {
        display: flex;
      }
      .nav-right .search-box {
        display: none;
      }
    }

    .mobile-menu {
      display: none;
      position: fixed;
      top: 64px;
      left: 0;
      width: 100%;
      background: #FFFFFF;
      box-shadow: var(--shadow-nav);
      flex-direction: column;
      padding: 20px 24px;
      gap: 16px;
      z-index: 49;
    }

    .mobile-menu.active {
      display: flex;
    }

    .mobile-menu a {
      font-size: 16px;
      font-weight: 500;
      color: var(--text-body);
      padding: 8px 0;
      border-bottom: 1px solid var(--border-light);
    }

    .mobile-menu .search-box {
      display: flex;
      width: 100%;
    }

    /* Hero */
    .hero {
      min-height: 80vh;
      display: flex;
      align-items: center;
      background: linear-gradient(180deg, #FAFBFC 0%, #F0F2F5 100%);
      padding-top: 64px;
    }

    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
    }

    .hero-content h1 {
      font-size: 48px;
      font-weight: 700;
      line-height: 1.2;
      color: var(--text-heading);
      margin-bottom: 20px;
    }

    .hero-content p {
      font-size: 18px;
      color: var(--text-muted);
      margin-bottom: 32px;
      max-width: 90%;
    }

    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }

    .hero-visual {
      position: relative;
      border-radius: var(--radius-lg);
      overflow: hidden;
      box-shadow: 0 0 40px rgba(10,224,140,0.15);
      animation: breathe 4s ease-in-out infinite;
    }

    @keyframes breathe {
      0% { transform: scale(1); }
      50% { transform: scale(1.02); }
      100% { transform: scale(1); }
    }

    .hero-visual img {
      width: 100%;
      display: block;
    }

    @media (max-width: 768px) {
      .hero-grid {
        grid-template-columns: 1fr;
        text-align: center;
      }
      .hero-content h1 {
        font-size: 32px;
      }
      .hero-content p {
        max-width: 100%;
      }
      .hero-buttons {
        justify-content: center;
      }
      .hero-visual {
        max-width: 400px;
        margin: 0 auto;
      }
    }

    section {
      padding: var(--space-section) 0;
    }

    @media (max-width: 640px) {
      section {
        padding: var(--space-mobile) 0;
      }
    }

    .section-title {
      font-size: 36px;
      font-weight: 600;
      color: var(--text-heading);
      margin-bottom: 16px;
      text-align: center;
    }

    .section-sub {
      color: var(--text-muted);
      text-align: center;
      max-width: 700px;
      margin: 0 auto 48px;
    }

    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }

    .grid-4 {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
    }

    @media (max-width: 1024px) {
      .grid-4 {
        grid-template-columns: repeat(2, 1fr);
      }
      .grid-3 {
        grid-template-columns: 1fr;
        max-width: 500px;
        margin: 0 auto;
      }
    }

    @media (max-width: 640px) {
      .grid-4, .grid-3 {
        grid-template-columns: 1fr;
      }
    }

    .pain-card {
      background: var(--bg-card);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      padding: 32px 24px;
      transition: all 0.25s ease;
      text-align: center;
    }

    .pain-card:hover {
      border-color: var(--primary);
      transform: translateY(-4px);
      box-shadow: var(--shadow-card-hover);
    }

    .pain-card .icon {
      font-size: 32px;
      margin-bottom: 16px;
    }

    .pain-card h4 {
      font-size: 20px;
      font-weight: 600;
      margin-bottom: 8px;
      color: var(--text-heading);
    }

    .solution-row {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
    }

    .solution-text h3 {
      font-size: 28px;
      font-weight: 600;
      margin-bottom: 16px;
    }

    .solution-text ul {
      list-style: none;
      margin-top: 20px;
    }

    .solution-text li {
      padding-left: 28px;
      position: relative;
      margin-bottom: 12px;
      border-left: 3px solid var(--primary);
      padding-left: 16px;
    }

    .solution-text li::before {
      content: "✓";
      color: var(--primary);
      font-weight: bold;
      margin-right: 8px;
    }

    .feature-card {
      background: #F9FAFB;
      border-radius: var(--radius-md);
      padding: 28px 20px;
      transition: 0.2s;
      border-top: 3px solid transparent;
      text-align: center;
    }

    .feature-card:hover {
      background: #FFFFFF;
      border-top-color: var(--primary);
      box-shadow: var(--shadow-card-hover);
    }

    .metrics {
      background: var(--secondary);
      color: white;
      border-radius: var(--radius-lg);
      padding: 60px 20px;
    }

    .metrics-grid {
      display: flex;
      justify-content: space-around;
      flex-wrap: wrap;
      text-align: center;
      gap: 30px;
    }

    .metric-number {
      font-size: 42px;
      font-weight: 700;
      color: var(--primary);
    }

    .testimonial-card {
      background: white;
      border-left: 4px solid var(--primary);
      border-radius: var(--radius-md);
      padding: 28px;
      transition: 0.2s;
    }

    .testimonial-card:hover {
      box-shadow: 0 4px 16px rgba(0,0,0,0.06);
    }

    .faq-item {
      border-bottom: 1px solid #EAEAEA;
      padding: 20px 0;
      cursor: pointer;
    }

    .faq-question {
      font-weight: 500;
      display: flex;
      align-items: center;
      gap: 8px;
    }

    .faq-answer {
      color: #4B5563;
      margin-top: 12px;
      display: none;
      padding-left: 28px;
    }

    .faq-item.open .faq-answer {
      display: block;
    }

    .cta-final {
      background: linear-gradient(135deg, var(--primary), #07b372);
      border-radius: var(--radius-lg);
      padding: 70px 20px;
      text-align: center;
      color: white;
    }

    .footer {
      background: #F3F4F6;
      border-top: 1px solid #E5E7EB;
      padding: 60px 0 20px;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 30px;
    }

    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr;
      }
      .solution-row {
        grid-template-columns: 1fr;
      }
    }

    .copyright {
      background: #E5E7EB;
      color: #9CA3AF;
      text-align: center;
      padding: 16px;
      margin-top: 40px;
    }