/* roulang page: index */
:root {
      --primary: #4E6EF2;
      --primary-hover: #3A5CE4;
      --green: #00B578;
      --orange: #FF9F0A;
      --red: #FA5151;
      --text-main: #1F2329;
      --text-secondary: #86909C;
      --border-light: #E5E8EF;
      --card-bg: #FFFFFF;
      --global-bg: #F5F6FA;
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-pill: 20px;
      --radius-tag: 4px;
      --shadow-card: 0 2px 8px rgba(0,0,0,0.04), 0 4px 16px rgba(0,0,0,0.04);
      --shadow-card-hover: 0 4px 12px rgba(0,0,0,0.08), 0 8px 24px rgba(0,0,0,0.06);
      --font-h1: 36px;
      --font-h2: 28px;
      --font-h3: 20px;
      --font-body: 16px;
      --font-small: 14px;
      --font-tag: 12px;
      --max-width: 1200px;
      --header-height: 64px;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', system-ui, -apple-system, sans-serif;
      background-color: var(--global-bg);
      color: var(--text-main);
      line-height: 1.6;
      min-height: 100vh;
      display: flex;
      flex-direction: column;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    button, input, textarea {
      font-family: inherit;
    }
    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
      width: 100%;
    }

    /* Header */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 100;
      background: #FFFFFF;
      height: var(--header-height);
      box-shadow: 0 1px 4px rgba(0,0,0,0.04);
      display: flex;
      align-items: center;
      justify-content: center;
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }
    .logo {
      display: flex;
      align-items: baseline;
      gap: 6px;
    }
    .logo-main {
      font-size: 20px;
      font-weight: 700;
      color: var(--primary);
      letter-spacing: 0.5px;
    }
    .logo-sub {
      font-size: 12px;
      color: var(--text-secondary);
      font-weight: 400;
      letter-spacing: 0.3px;
    }
    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
    }
    .nav-links a {
      font-size: 14px;
      color: var(--text-main);
      padding: 8px 0;
      border-bottom: 2px solid transparent;
      transition: color 0.2s, border-color 0.2s;
      font-weight: 500;
    }
    .nav-links a:hover {
      color: var(--primary);
      border-bottom-color: var(--primary);
    }
    .mobile-nav {
      display: none;
      position: fixed;
      bottom: 16px;
      left: 50%;
      transform: translateX(-50%);
      background: #FFFFFF;
      border-radius: 20px;
      box-shadow: 0 4px 20px rgba(0,0,0,0.08);
      padding: 8px 20px;
      z-index: 200;
      width: fit-content;
      gap: 24px;
      align-items: center;
      justify-content: center;
      backdrop-filter: blur(8px);
    }
    .mobile-nav a {
      display: flex;
      flex-direction: column;
      align-items: center;
      font-size: 10px;
      color: var(--text-secondary);
      gap: 2px;
      transition: color 0.2s;
    }
    .mobile-nav a i {
      font-size: 20px;
      width: 24px;
      text-align: center;
    }
    .mobile-nav a.active, .mobile-nav a:hover {
      color: var(--primary);
    }

    /* Hero */
    .hero-section {
      padding: 80px 0 100px;
      background: #FFFFFF;
      margin-bottom: 24px;
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 60px;
    }
    .hero-text {
      flex: 1;
    }
    .hero-text h1 {
      font-size: var(--font-h1);
      font-weight: 600;
      line-height: 1.3;
      color: var(--text-main);
      margin-bottom: 16px;
    }
    .hero-sub {
      font-size: var(--font-body);
      color: var(--text-secondary);
      margin-bottom: 32px;
      line-height: 1.6;
    }
    .hero-actions {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      border: none;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-size: 16px;
      font-weight: 500;
      cursor: pointer;
      transition: background 0.2s, transform 0.2s;
      display: inline-flex;
      align-items: center;
      justify-content: center;
    }
    .btn-primary:hover {
      background: var(--primary-hover);
      transform: translateY(-1px);
    }
    .btn-outline {
      background: transparent;
      border: 1px solid var(--border-light);
      color: var(--text-main);
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-size: 16px;
      font-weight: 500;
      cursor: pointer;
      transition: border-color 0.2s, color 0.2s, transform 0.2s;
    }
    .btn-outline:hover {
      border-color: var(--primary);
      color: var(--primary);
      transform: translateY(-1px);
    }
    .hero-image {
      flex: 1;
      background: #E5E8EF;
      border-radius: var(--radius-card);
      height: 400px;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      box-shadow: var(--shadow-card);
    }

    /* Highlights */
    .highlights-section {
      padding: 80px 0;
    }
    .section-title {
      font-size: var(--font-h2);
      font-weight: 600;
      margin-bottom: 48px;
      text-align: center;
      color: var(--text-main);
    }
    .highlights-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .highlight-card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 24px;
      box-shadow: var(--shadow-card);
      transition: box-shadow 0.2s, transform 0.2s;
      display: flex;
      flex-direction: column;
      gap: 16px;
    }
    .highlight-card:hover {
      box-shadow: var(--shadow-card-hover);
      transform: translateY(-2px);
    }
    .highlight-icon {
      width: 40px;
      height: 40px;
      background: #EEF1FD;
      border-radius: 8px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: var(--primary);
      font-size: 22px;
    }
    .highlight-card h3 {
      font-size: var(--font-h3);
      font-weight: 500;
    }
    .highlight-card p {
      font-size: var(--font-small);
      color: var(--text-secondary);
      line-height: 1.5;
    }

    /* Cases */
    .cases-section {
      padding: 80px 0;
    }
    .cases-masonry {
      columns: 3 280px;
      column-gap: 24px;
    }
    .case-card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      margin-bottom: 24px;
      break-inside: avoid;
      overflow: hidden;
      transition: box-shadow 0.2s, transform 0.2s;
    }
    .case-card:hover {
      box-shadow: var(--shadow-card-hover);
      transform: translateY(-2px);
    }
    .case-img {
      width: 100%;
      aspect-ratio: 16/9;
      object-fit: cover;
      background: #E5E8EF;
    }
    .case-body {
      padding: 16px;
    }
    .case-tag {
      font-size: var(--font-tag);
      background: #EEF1FD;
      color: var(--primary);
      padding: 2px 8px;
      border-radius: var(--radius-tag);
      display: inline-block;
      margin-bottom: 8px;
    }
    .case-body h3 {
      font-size: 18px;
      font-weight: 500;
      margin-bottom: 6px;
    }
    .case-body p {
      font-size: var(--font-small);
      color: var(--text-secondary);
    }

    /* Comparison */
    .comparison-section {
      padding: 80px 0;
    }
    .comparison-table {
      display: grid;
      grid-template-columns: 1fr 1fr;
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-card);
    }
    .comp-col {
      padding: 24px;
    }
    .comp-left {
      background: #F5F6FA;
    }
    .comp-right {
      background: #FFFFFF;
      border-left: 2px solid var(--primary);
    }
    .comp-row {
      display: flex;
      justify-content: space-between;
      padding: 16px 0;
      font-size: var(--font-small);
      border-bottom: 1px solid var(--border-light);
    }
    .comp-row:last-child {
      border-bottom: none;
    }
    .comp-label {
      font-weight: 500;
    }
    .comp-value {
      color: var(--text-main);
    }
    .comp-right .comp-value {
      font-weight: 600;
      color: var(--green);
    }
    .comp-header {
      font-size: 18px;
      font-weight: 600;
      margin-bottom: 16px;
    }

    /* FAQ */
    .faq-section {
      padding: 80px 0;
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-list {
      display: flex;
      flex-direction: column;
      gap: 16px;
    }
    .faq-item {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      padding: 20px 24px;
      cursor: pointer;
      transition: box-shadow 0.2s;
    }
    .faq-item:hover {
      box-shadow: var(--shadow-card-hover);
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-size: 16px;
      font-weight: 500;
    }
    .faq-icon {
      font-size: 20px;
      color: var(--primary);
      transition: transform 0.2s;
    }
    .faq-answer {
      font-size: var(--font-small);
      color: var(--text-secondary);
      margin-top: 12px;
      display: none;
      line-height: 1.6;
    }
    .faq-item.open .faq-answer {
      display: block;
    }
    .faq-item.open .faq-icon {
      transform: rotate(45deg);
    }

    /* CTA */
    .cta-section {
      padding: 100px 0;
      text-align: center;
      background: #FFFFFF;
      border-radius: var(--radius-card);
      margin: 0 24px 80px;
      box-shadow: var(--shadow-card);
    }
    .cta-section h2 {
      font-size: var(--font-h2);
      font-weight: 600;
      margin-bottom: 16px;
    }
    .cta-section p {
      color: var(--text-secondary);
      margin-bottom: 32px;
      font-size: var(--font-body);
    }
    .cta-btn {
      padding: 16px 40px;
      font-size: 18px;
      background: var(--primary);
      color: white;
      border: none;
      border-radius: var(--radius-btn);
      cursor: pointer;
      transition: background 0.2s;
      display: inline-block;
      margin-bottom: 16px;
    }
    .cta-btn:hover {
      background: var(--primary-hover);
    }
    .cta-link {
      color: var(--primary);
      font-size: var(--font-small);
      text-decoration: underline;
      display: block;
    }

    /* Footer */
    .site-footer {
      background: #FFFFFF;
      padding: 48px 0 32px;
      border-top: 1px solid var(--border-light);
      margin-top: auto;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    .footer-col h4 {
      font-size: 16px;
      font-weight: 600;
      margin-bottom: 16px;
    }
    .footer-col p, .footer-col a {
      font-size: var(--font-small);
      color: var(--text-secondary);
      line-height: 2;
      display: block;
    }
    .footer-col a:hover {
      color: var(--primary);
    }
    .copyright {
      margin-top: 32px;
      font-size: 12px;
      color: var(--text-secondary);
      text-align: center;
    }

    /* Responsive */
    @media (max-width: 768px) {
      .nav-links {
        display: none;
      }
      .mobile-nav {
        display: flex;
      }
      .hero-grid {
        flex-direction: column;
        text-align: center;
      }
      .hero-image {
        height: 250px;
        order: -1;
      }
      .highlights-grid {
        grid-template-columns: 1fr;
      }
      .cases-masonry {
        columns: 1;
      }
      .comparison-table {
        grid-template-columns: 1fr;
      }
      .comp-right {
        border-left: none;
        border-top: 2px solid var(--primary);
      }
      .footer-grid {
        grid-template-columns: 1fr;
        gap: 24px;
      }
      :root {
        --font-h1: 28px;
        --font-h2: 22px;
      }
      .container {
        padding: 0 16px;
      }
      .cta-section {
        margin: 0 16px 60px;
      }
    }