/* roulang page: index */
:root {
      --primary: #2E6BD9;
      --primary-dark: #1F54C0;
      --primary-light: #EBF1FD;
      --accent: #F57C38;
      --accent-dark: #E06A2B;
      --success: #1FA089;
      --bg: #F9FAFB;
      --card-bg: #FFFFFF;
      --soft-bg: #EEF2F8;
      --dark-bg: #1F2937;
      --text-main: #111827;
      --text-body: #374151;
      --text-muted: #6B7280;
      --border-light: #E5E7EB;
      --white: #FFFFFF;
      --shadow-sm: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 24px rgba(0,0,0,0.10);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 6px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "Noto Sans SC", system-ui, sans-serif;
      --font-number: "Inter", "SF Pro Text", -apple-system, sans-serif;
      --max-width: 1200px;
      --section-gap: 100px;
      --section-gap-mobile: 64px;
      --transition: 0.25s ease;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--bg);
      color: var(--text-body);
      line-height: 1.6;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
    }
    img {
      display: block;
      max-width: 100%;
      height: auto;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    button, .btn {
      cursor: pointer;
      font-family: inherit;
    }
    h1, h2, h3, h4 {
      color: var(--text-main);
      font-weight: 700;
    }
    h1 {
      font-size: 2.8rem;
      line-height: 1.25;
    }
    h2 {
      font-size: 2rem;
      margin-bottom: 48px;
      text-align: center;
      position: relative;
    }
    h3 {
      font-size: 1.5rem;
      font-weight: 600;
    }
    h4 {
      font-size: 1.25rem;
      font-weight: 600;
    }
    .section {
      padding: var(--section-gap) 0;
    }
    .soft-bg {
      background-color: var(--soft-bg);
    }
    /* 导航 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      background: rgba(255,255,255,0.85);
      backdrop-filter: blur(12px);
      border-bottom: 1px solid transparent;
      transition: background var(--transition), box-shadow var(--transition), border-color var(--transition);
    }
    .header.scrolled {
      background: var(--white);
      box-shadow: var(--shadow-sm);
      border-bottom-color: var(--border-light);
    }
    .nav {
      display: flex;
      align-items: center;
      justify-content: space-between;
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 16px 24px;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 700;
      font-size: 1.5rem;
      color: var(--text-main);
      letter-spacing: -0.5px;
    }
    .logo-icon {
      width: 36px;
      height: 36px;
      background: linear-gradient(135deg, var(--primary), #4F8AF0);
      border-radius: 10px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-size: 20px;
      position: relative;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
      list-style: none;
    }
    .nav-links a {
      color: var(--text-body);
      font-weight: 500;
      transition: color var(--transition);
      font-size: 15px;
    }
    .nav-links a:hover {
      color: var(--primary);
    }
    .btn-nav {
      background: var(--accent);
      color: var(--white) !important;
      padding: 10px 22px;
      border-radius: 24px;
      font-weight: 600;
      transition: background var(--transition), transform var(--transition);
    }
    .btn-nav:hover {
      background: var(--accent-dark);
      transform: translateY(-1px);
    }
    .hamburger {
      display: none;
      background: none;
      border: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--text-main);
      transition: var(--transition);
    }
    /* 按钮系统 */
    .btn-primary {
      background: var(--primary);
      color: var(--white);
      font-weight: 600;
      padding: 14px 28px;
      border-radius: var(--radius-btn);
      border: none;
      box-shadow: var(--shadow-sm);
      transition: background var(--transition), transform var(--transition), box-shadow var(--transition);
      display: inline-block;
      text-align: center;
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      transform: translateY(-2px);
      box-shadow: var(--shadow-md);
    }
    .btn-outline {
      background: transparent;
      color: var(--primary);
      border: 2px solid var(--primary);
      font-weight: 600;
      padding: 14px 28px;
      border-radius: var(--radius-btn);
      transition: background var(--transition), color var(--transition), transform var(--transition);
      display: inline-block;
      text-align: center;
    }
    .btn-outline:hover {
      background: var(--primary-light);
      transform: translateY(-2px);
    }
    .btn-accent {
      background: var(--accent);
      color: var(--white);
      font-weight: 600;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      border: none;
      transition: background var(--transition), transform var(--transition);
      display: inline-block;
    }
    .btn-accent:hover {
      background: var(--accent-dark);
      transform: scale(1.02);
    }
    /* 卡片 */
    .card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 28px;
      box-shadow: var(--shadow-sm);
      transition: box-shadow var(--transition), transform var(--transition);
    }
    .card:hover {
      box-shadow: var(--shadow-md);
      transform: translateY(-4px);
    }
    /* 网格 */
    .grid-2, .grid-3, .grid-4 {
      display: grid;
      gap: 24px;
    }
    .grid-2 { grid-template-columns: 1fr 1fr; }
    .grid-3 { grid-template-columns: repeat(3, 1fr); }
    .grid-4 { grid-template-columns: repeat(4, 1fr); }
    /* Hero */
    .hero {
      min-height: 100vh;
      display: flex;
      align-items: center;
      background: linear-gradient(135deg, #F9FAFB 0%, #DEE9FC 100%);
      position: relative;
      overflow: hidden;
      padding-top: 80px;
    }
    .hero-content {
      display: flex;
      align-items: center;
      gap: 60px;
    }
    .hero-text {
      flex: 1;
    }
    .hero-text h1 {
      margin-bottom: 20px;
    }
    .hero-text p {
      font-size: 1.2rem;
      color: var(--text-body);
      margin-bottom: 32px;
      max-width: 500px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .hero-image {
      flex: 1;
      position: relative;
      display: flex;
      justify-content: center;
      align-items: center;
    }
    .hero-mockup {
      max-width: 320px;
      filter: drop-shadow(0 20px 30px rgba(0,0,0,0.15));
      animation: float 4s ease-in-out infinite;
    }
    @keyframes float {
      0% { transform: translateY(0px); }
      50% { transform: translateY(-12px); }
      100% { transform: translateY(0px); }
    }
    .cloud-decoration {
      position: absolute;
      right: 5%;
      bottom: 10%;
      width: 200px;
      height: 120px;
      background: radial-gradient(circle at 30% 40%, rgba(255,255,255,0.6) 0%, transparent 70%);
      border-radius: 50%;
      filter: blur(20px);
      opacity: 0.4;
    }
    /* 特性卡片 */
    .feature-icon {
      width: 56px;
      height: 56px;
      background: var(--primary-light);
      border-radius: 14px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
      color: var(--primary);
      font-size: 26px;
    }
    /* 解决方案卡片 */
    .solution-card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
      transition: all var(--transition);
    }
    .solution-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-md);
    }
    .solution-card img {
      width: 100%;
      height: 200px;
      object-fit: cover;
      transition: transform 0.4s ease;
    }
    .solution-card:hover img {
      transform: scale(1.03);
    }
    .solution-body {
      padding: 24px;
    }
    .feature-list {
      list-style: none;
      margin: 16px 0;
    }
    .feature-list li {
      display: flex;
      align-items: center;
      gap: 8px;
      margin-bottom: 8px;
      color: var(--text-body);
      font-size: 15px;
    }
    .check-icon {
      color: var(--success);
      font-weight: bold;
    }
    .text-link {
      color: var(--primary);
      font-weight: 600;
      transition: color var(--transition);
      cursor: pointer;
    }
    .text-link:hover {
      color: var(--accent);
      text-decoration: underline;
    }
    /* 证言卡片 */
    .testimonial-card {
      background: var(--white);
      border-radius: var(--radius-card);
      padding: 28px;
      box-shadow: var(--shadow-sm);
      position: relative;
    }
    .testimonial-avatar {
      width: 48px;
      height: 48px;
      border-radius: 50%;
      object-fit: cover;
      margin-bottom: 16px;
    }
    .testimonial-text {
      font-style: italic;
      color: var(--text-body);
      margin-bottom: 20px;
      position: relative;
    }
    .testimonial-text::before {
      content: "“";
      font-size: 3rem;
      color: var(--accent);
      position: absolute;
      left: -10px;
      top: -15px;
      opacity: 0.4;
    }
    .testimonial-author {
      font-weight: 600;
      color: var(--text-main);
    }
    /* FAQ */
    details {
      background: var(--white);
      border-radius: var(--radius-card);
      padding: 0 20px;
      margin-bottom: 12px;
      box-shadow: var(--shadow-sm);
      transition: all var(--transition);
    }
    details[open] {
      background: var(--soft-bg);
    }
    summary {
      list-style: none;
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 18px 0;
      font-weight: 600;
      font-size: 1.1rem;
      cursor: pointer;
      color: var(--text-main);
    }
    summary::-webkit-details-marker {
      display: none;
    }
    .faq-icon {
      font-size: 1.2rem;
      transition: transform 0.2s ease;
    }
    details[open] .faq-icon {
      transform: rotate(45deg);
    }
    .faq-content {
      padding-bottom: 20px;
      color: var(--text-body);
    }
    /* 联系表单 */
    .contact-form input, .contact-form textarea {
      width: 100%;
      padding: 14px;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-input);
      font-family: inherit;
      margin-bottom: 16px;
      transition: border var(--transition), box-shadow var(--transition);
    }
    .contact-form input:focus, .contact-form textarea:focus {
      outline: none;
      border-color: var(--primary);
      box-shadow: 0 0 0 3px rgba(46,107,217,0.2);
    }
    .contact-info-item {
      display: flex;
      align-items: center;
      gap: 12px;
      margin-bottom: 18px;
    }
    /* CTA 横幅 */
    .cta-banner {
      background: linear-gradient(135deg, #1E4DB0, #2E6BD9);
      color: white;
      text-align: center;
      padding: 80px 24px;
      border-radius: 24px;
      margin: 0 24px;
    }
    /* 页脚 */
    .footer {
      background: var(--dark-bg);
      color: #CBD5E1;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    .footer a {
      color: #CBD5E1;
      transition: color var(--transition);
    }
    .footer a:hover {
      color: white;
    }
    .copyright {
      border-top: 1px solid #374151;
      margin-top: 40px;
      padding-top: 24px;
      text-align: center;
      font-size: 14px;
    }
    /* 响应式 */
    @media (max-width: 1024px) {
      .grid-4 { grid-template-columns: repeat(2, 1fr); }
      .grid-3 { grid-template-columns: 1fr; }
      .hero-content {
        flex-direction: column;
        text-align: center;
      }
      .hero-text p {
        max-width: 100%;
      }
      .hero-buttons {
        justify-content: center;
      }
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
    }
    @media (max-width: 768px) {
      h1 { font-size: 2rem; }
      h2 { font-size: 1.6rem; }
      .section { padding: var(--section-gap-mobile) 0; }
      .grid-2, .grid-4 { grid-template-columns: 1fr; }
      .nav-links {
        display: none;
        position: absolute;
        top: 70px;
        left: 0;
        width: 100%;
        background: white;
        flex-direction: column;
        padding: 24px;
        box-shadow: var(--shadow-md);
        gap: 20px;
      }
      .nav-links.active {
        display: flex;
      }
      .hamburger {
        display: flex;
      }
      .hero {
        min-height: auto;
        padding: 120px 0 60px;
      }
      .hero-mockup {
        max-width: 240px;
      }
      .cta-banner {
        margin: 0 16px;
        padding: 48px 16px;
      }
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }