/* roulang page: index */
:root {
      --primary: #6C3CF0;
      --primary-dark: #5B2ED8;
      --accent: #FF5F1F;
      --accent-dark: #E8520A;
      --bg-light: #F7F6FA;
      --bg-dark: #1A1A1E;
      --white: #FFFFFF;
      --text-dark: #1A1A1E;
      --text-mid: #5A5766;
      --text-light: #B0AEBF;
      --border-light: #E8E6F0;
      --shadow-sm: 0 4px 20px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 32px rgba(108,60,240,0.08);
      --shadow-accent: 0 6px 24px rgba(255,95,31,0.25);
      --radius-md: 16px;
      --radius-btn: 10px;
      --font-head: 'Inter', 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', system-ui, sans-serif;
      --font-body: 'Inter', 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', system-ui, sans-serif;
      --transition-smooth: 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    html {
      scroll-behavior: smooth;
    }
    body {
      font-family: var(--font-body);
      font-weight: 400;
      line-height: 1.6;
      color: var(--text-dark);
      background-color: var(--bg-light);
      -webkit-font-smoothing: antialiased;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition-smooth);
    }
    button, .btn {
      cursor: pointer;
      font-family: var(--font-body);
      font-weight: 600;
      border: none;
      background: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      transition: var(--transition-smooth);
      border-radius: var(--radius-btn);
    }
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 40px;
    }
    @media (max-width: 768px) {
      .container {
        padding: 0 20px;
      }
    }
    @media (max-width: 480px) {
      .container {
        padding: 0 16px;
      }
    }

    /* 导航 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: rgba(247, 246, 250, 0.85);
      backdrop-filter: blur(12px);
      z-index: 100;
      border-bottom: 1px solid transparent;
      transition: var(--transition-smooth);
    }
    .site-header.scrolled {
      border-bottom-color: var(--border-light);
      box-shadow: 0 2px 12px rgba(0,0,0,0.04);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 40px;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 8px;
      font-weight: 700;
      font-size: 1.6rem;
      letter-spacing: -0.02em;
      color: var(--text-dark);
      font-family: var(--font-head);
    }
    .logo svg {
      width: 28px;
      height: 28px;
      fill: var(--primary);
    }
    .nav-left, .nav-right {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-link {
      font-weight: 500;
      font-size: 1rem;
      color: var(--text-mid);
      position: relative;
      padding: 4px 0;
    }
    .nav-link::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 50%;
      width: 0;
      height: 2px;
      background: var(--primary);
      transition: width 0.25s ease, left 0.25s ease;
    }
    .nav-link:hover {
      color: var(--primary);
    }
    .nav-link:hover::after {
      width: 100%;
      left: 0;
    }
    .menu-toggle {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      padding: 8px;
    }
    .menu-toggle span {
      display: block;
      width: 24px;
      height: 2px;
      background: var(--text-dark);
      transition: var(--transition-smooth);
    }
    @media (max-width: 768px) {
      .nav-left, .nav-right {
        display: none;
      }
      .menu-toggle {
        display: flex;
      }
      .nav-container {
        justify-content: space-between;
      }
      .mobile-nav {
        position: fixed;
        top: 72px;
        left: 0;
        width: 100%;
        background: var(--bg-dark);
        padding: 32px 20px;
        flex-direction: column;
        gap: 28px;
        display: none;
        z-index: 99;
      }
      .mobile-nav.active {
        display: flex;
      }
      .mobile-nav .nav-link {
        color: var(--white);
        font-size: 1.2rem;
        font-weight: 500;
      }
    }

    /* 按钮系统 */
    .btn-primary {
      background: var(--primary);
      color: var(--white);
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      box-shadow: 0 6px 24px rgba(108,60,240,0.3);
      transform: scale(1.03);
    }
    .btn-secondary {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      padding: 14px 32px;
    }
    .btn-secondary:hover {
      background: var(--primary);
      color: var(--white);
    }
    .btn-accent {
      background: var(--accent);
      color: var(--white);
      padding: 16px 40px;
      font-size: 1.1rem;
      box-shadow: 0 6px 24px rgba(255,95,31,0.2);
    }
    .btn-accent:hover {
      background: var(--accent-dark);
      box-shadow: var(--shadow-accent);
      transform: scale(1.02);
    }
    @media (max-width: 480px) {
      .btn-primary, .btn-secondary, .btn-accent {
        width: 100%;
        justify-content: center;
        padding: 16px 24px;
      }
    }

    /* Hero */
    .hero {
      padding: 140px 0 100px;
      background: linear-gradient(180deg, #F7F6FA 0%, #EDE9FE 100%);
      position: relative;
      overflow: hidden;
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 60px;
    }
    .hero-content {
      flex: 1;
    }
    .hero h1 {
      font-family: var(--font-head);
      font-size: 52px;
      font-weight: 800;
      line-height: 1.15;
      letter-spacing: -0.02em;
      color: var(--text-dark);
      margin-bottom: 20px;
    }
    .hero-sub {
      font-size: 1.2rem;
      color: var(--text-mid);
      margin-bottom: 32px;
      max-width: 480px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .hero-visual {
      flex: 1;
      position: relative;
    }
    .hero-visual img {
      border-radius: 24px;
      box-shadow: 0 20px 40px rgba(108,60,240,0.12);
    }
    @media (max-width: 768px) {
      .hero-grid {
        flex-direction: column;
        text-align: center;
      }
      .hero h1 {
        font-size: 38px;
      }
      .hero-sub {
        max-width: 100%;
      }
      .hero-buttons {
        justify-content: center;
      }
    }

    /* 通用板块 */
    .section {
      padding: 100px 0;
    }
    .section-dark {
      background: var(--bg-dark);
      color: var(--white);
    }
    .section-title {
      font-family: var(--font-head);
      font-size: 38px;
      font-weight: 700;
      letter-spacing: -0.02em;
      margin-bottom: 16px;
      color: inherit;
    }
    .section-desc {
      font-size: 1.1rem;
      color: var(--text-mid);
      max-width: 600px;
      margin-bottom: 48px;
    }
    .section-dark .section-desc {
      color: var(--text-light);
    }
    @media (max-width: 768px) {
      .section {
        padding: 70px 0;
      }
      .section-title {
        font-size: 30px;
      }
    }

    /* 功能卡片 */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }
    .feature-card {
      background: var(--white);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      padding: 28px;
      display: flex;
      gap: 20px;
      align-items: flex-start;
      transition: var(--transition-smooth);
      box-shadow: var(--shadow-sm);
    }
    .feature-icon {
      width: 48px;
      height: 48px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: var(--primary);
      flex-shrink: 0;
    }
    .feature-text h3 {
      font-family: var(--font-head);
      font-size: 1.3rem;
      font-weight: 600;
      margin-bottom: 8px;
    }
    .feature-text p {
      color: var(--text-mid);
      font-size: 0.95rem;
    }
    .feature-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
      border-color: rgba(108,60,240,0.2);
    }
    @media (max-width: 1024px) {
      .features-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    @media (max-width: 600px) {
      .features-grid {
        grid-template-columns: 1fr;
      }
    }

    /* 场景卡片 */
    .scenarios-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }
    .scenario-card {
      background: var(--white);
      border-radius: var(--radius-md);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
      transition: var(--transition-smooth);
    }
    .scenario-card img {
      width: 100%;
      height: 200px;
      object-fit: cover;
    }
    .scenario-info {
      padding: 24px;
    }
    .scenario-info h3 {
      font-weight: 700;
      margin-bottom: 8px;
    }
    .scenario-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }
    @media (max-width: 768px) {
      .scenarios-grid {
        grid-template-columns: 1fr;
      }
    }

    /* 案例 */
    .case-row {
      display: flex;
      align-items: center;
      gap: 48px;
      margin-bottom: 48px;
    }
    .case-data {
      flex: 0 0 200px;
      font-size: 3rem;
      font-weight: 800;
      color: var(--primary);
      line-height: 1;
    }
    .case-quote {
      flex: 1;
      font-style: italic;
      border-left: 4px solid var(--accent);
      padding-left: 24px;
      color: var(--text-mid);
    }
    @media (max-width: 768px) {
      .case-row {
        flex-direction: column;
        gap: 20px;
      }
    }

    /* 价格 */
    .pricing-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }
    .pricing-card {
      background: var(--white);
      border-radius: var(--radius-md);
      padding: 32px;
      border: 1px solid var(--border-light);
      display: flex;
      flex-direction: column;
    }
    .pricing-card.featured {
      border-left: 4px solid var(--accent);
      background: #FFF9F6;
    }
    .price {
      font-size: 2.8rem;
      font-weight: 800;
      margin: 16px 0;
    }
    @media (max-width: 768px) {
      .pricing-grid {
        grid-template-columns: 1fr;
      }
    }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 18px 0;
    }
    .faq-question {
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      cursor: pointer;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-mid);
    }

    /* 页脚 */
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1.5fr;
      gap: 40px;
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }