/* roulang page: index */
:root {
      --primary: #2563EB;
      --primary-dark: #1D4ED8;
      --primary-light: #EFF6FF;
      --accent: #F59E0B;
      --accent-dark: #D97706;
      --bg-white: #FFFFFF;
      --bg-light: #F8FAFC;
      --bg-dark: #1E293B;
      --text-primary: #1E293B;
      --text-secondary: #64748B;
      --text-on-primary: #FFFFFF;
      --border-light: #E2E8F0;
      --shadow-card: 0 4px 20px rgba(0,0,0,0.04);
      --shadow-hover: 0 12px 32px rgba(0,0,0,0.08);
      --radius-md: 12px;
      --radius-lg: 16px;
      --radius-xl: 24px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --transition: 0.3s ease;
      --section-gap: 100px;
      --container-max: 1280px;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--bg-white);
      color: var(--text-primary);
      line-height: 1.7;
      -webkit-font-smoothing: antialiased;
    }

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

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

    button, .btn {
      cursor: pointer;
      font-family: inherit;
    }

    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 32px;
    }

    /* 导航 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(12px);
      height: 72px;
      display: flex;
      align-items: center;
      z-index: 50;
      border-bottom: 1px solid var(--border-light);
    }

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

    .logo {
      display: flex;
      align-items: center;
      gap: 8px;
      font-weight: 700;
      font-size: 1.5rem;
      color: var(--primary);
    }
    .logo i {
      font-size: 1.8rem;
      color: var(--accent);
    }

    .nav-menu {
      display: flex;
      gap: 32px;
      align-items: center;
    }

    .nav-link {
      font-weight: 500;
      color: var(--text-secondary);
      padding: 8px 0;
      border-bottom: 3px solid transparent;
      transition: var(--transition);
    }

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

    .mobile-toggle {
      display: none;
      background: none;
      border: none;
      font-size: 1.8rem;
      color: var(--text-primary);
    }

    /* 按钮系统 */
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 14px 32px;
      border-radius: var(--radius-md);
      font-weight: 600;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      border: none;
      transition: var(--transition);
      box-shadow: 0 4px 10px rgba(37,99,235,0.25);
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      transform: scale(1.02);
      box-shadow: 0 8px 18px rgba(37,99,235,0.3);
    }

    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      padding: 14px 32px;
      border-radius: var(--radius-md);
      font-weight: 600;
      transition: var(--transition);
    }
    .btn-outline:hover {
      background: var(--primary-light);
    }

    .btn-accent {
      background: var(--accent);
      color: white;
      padding: 16px 40px;
      border-radius: var(--radius-md);
      font-weight: 700;
      border: none;
      transition: var(--transition);
      box-shadow: 0 6px 16px rgba(245,158,11,0.3);
    }
    .btn-accent:hover {
      background: var(--accent-dark);
      transform: scale(1.02);
    }

    /* 板块通用 */
    section {
      padding: var(--section-gap) 0;
    }

    .section-title {
      font-size: 2.25rem;
      font-weight: 700;
      margin-bottom: 16px;
      color: var(--text-primary);
    }
    .section-sub {
      color: var(--text-secondary);
      font-size: 1.125rem;
      max-width: 600px;
    }

    /* Hero */
    .hero {
      padding-top: 140px;
      padding-bottom: 80px;
      display: flex;
      align-items: center;
      gap: 40px;
    }
    .hero-content {
      flex: 1;
    }
    .hero h1 {
      font-size: 3rem;
      font-weight: 800;
      line-height: 1.2;
      margin-bottom: 20px;
      color: var(--text-primary);
    }
    .hero p {
      font-size: 1.2rem;
      color: var(--text-secondary);
      margin-bottom: 32px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .hero-image {
      flex: 1;
      display: flex;
      justify-content: flex-end;
    }
    .hero-image img {
      max-width: 520px;
      animation: float 6s ease-in-out infinite;
    }
    @keyframes float {
      0% { transform: translateY(0px); }
      50% { transform: translateY(-12px); }
      100% { transform: translateY(0px); }
    }

    /* 痛点条 */
    .pain-grid {
      display: grid;
      grid-template-columns: repeat(2,1fr);
      gap: 24px;
    }
    .pain-item {
      background: #FEF2F2;
      padding: 20px 24px;
      border-radius: var(--radius-lg);
      display: flex;
      align-items: center;
      gap: 16px;
      color: #B91C1C;
    }

    /* 解决方案卡片 */
    .cards-grid {
      display: grid;
      grid-template-columns: repeat(3,1fr);
      gap: 32px;
    }
    .sol-card {
      background: white;
      border-radius: var(--radius-lg);
      padding: 40px 32px;
      box-shadow: var(--shadow-card);
      text-align: center;
      transition: var(--transition);
    }
    .sol-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-hover);
    }
    .icon-circle {
      width: 72px;
      height: 72px;
      background: var(--primary-light);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 0 auto 24px;
      color: var(--primary);
      font-size: 2rem;
    }

    /* 数据大数字 */
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4,1fr);
      text-align: center;
      gap: 32px;
    }
    .stat-number {
      font-size: 3rem;
      font-weight: 800;
      color: var(--primary);
    }

    /* 证言 */
    .testimonials-grid {
      display: grid;
      grid-template-columns: repeat(3,1fr);
      gap: 32px;
    }
    .testimonial-card {
      background: #F1F5F9;
      border-radius: var(--radius-lg);
      padding: 32px;
    }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
    }
    .faq-question {
      width: 100%;
      background: none;
      border: none;
      text-align: left;
      padding: 18px 0;
      font-weight: 600;
      font-size: 1.1rem;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      background: #F8FAFC;
      border-radius: 8px;
      color: var(--text-secondary);
    }
    .faq-answer.open {
      max-height: 200px;
      padding: 16px;
      margin-bottom: 12px;
    }

    /* CTA band */
    .cta-band {
      background: linear-gradient(135deg, #2563EB 0%, #1E40AF 100%);
      color: white;
      text-align: center;
      border-radius: var(--radius-xl);
      padding: 80px 40px;
    }

    /* 页脚 */
    .site-footer {
      background: var(--bg-dark);
      color: #CBD5E1;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: repeat(4,1fr);
      gap: 40px;
    }

    @media (max-width: 1024px) {
      .cards-grid, .testimonials-grid { grid-template-columns: repeat(2,1fr); }
      .stats-grid { grid-template-columns: repeat(2,1fr); }
    }
    @media (max-width: 768px) {
      .container { padding: 0 20px; }
      .nav-menu {
        display: none;
        position: fixed; top: 72px; left: 0; width: 100%; background: white;
        flex-direction: column; padding: 32px; gap: 20px; box-shadow: 0 10px 20px rgba(0,0,0,0.05);
      }
      .nav-menu.open { display: flex; }
      .mobile-toggle { display: block; }
      .hero { flex-direction: column; padding-top: 120px; }
      .hero h1 { font-size: 2.4rem; }
      .pain-grid, .cards-grid, .testimonials-grid, .footer-grid { grid-template-columns: 1fr; }
      .stats-grid { grid-template-columns: 1fr 1fr; }
      section { padding: 60px 0; }
    }