/* roulang page: index */
:root {
      --primary: #4E6EF2;
      --primary-hover: #3A54D4;
      --green: #00B578;
      --orange: #FF9F0A;
      --red: #FA5151;
      --bg: #F5F6FA;
      --white: #FFFFFF;
      --text: #1F2329;
      --text-secondary: #86909C;
      --border-light: #E5E8EF;
      --border-input: #D0D5DD;
      --shadow-card: 0 2px 8px rgba(0,0,0,0.04);
      --shadow-card-hover: 0 6px 20px rgba(0,0,0,0.08);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 8px;
      --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --max-width: 1200px;
      --gap-section: 80px;
    }

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

    html {
      scroll-behavior: smooth;
    }

    body {
      font-family: var(--font-sans);
      background-color: var(--bg);
      color: var(--text);
      line-height: 1.5;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
    }

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

    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s ease;
    }

    button, input, textarea {
      font-family: inherit;
    }

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

    /* 导航 */
    #header {
      position: sticky;
      top: 0;
      z-index: 100;
      background: var(--white);
      border-bottom: 1px solid var(--border-light);
      transition: box-shadow 0.25s ease;
    }

    #header.scrolled {
      box-shadow: 0 2px 8px rgba(0,0,0,0.04);
    }

    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 64px;
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
    }

    .logo {
      font-size: 22px;
      font-weight: 700;
      color: var(--text);
      letter-spacing: 1px;
      white-space: nowrap;
      display: flex;
      align-items: center;
      gap: 4px;
    }
    .logo span {
      color: var(--primary);
    }

    .nav-menu {
      display: flex;
      align-items: center;
      gap: 32px;
      list-style: none;
    }

    .nav-link {
      font-size: 15px;
      font-weight: 500;
      color: var(--text);
      transition: color 0.2s;
      white-space: nowrap;
    }

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

    .btn-primary {
      background: var(--primary);
      color: white;
      border: none;
      padding: 10px 22px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 15px;
      cursor: pointer;
      transition: background 0.2s ease;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      white-space: nowrap;
    }
    .btn-primary:hover {
      background: var(--primary-hover);
    }

    .btn-outline {
      background: transparent;
      color: var(--primary);
      border: 1.5px solid var(--primary);
      padding: 10px 22px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 15px;
      cursor: pointer;
      transition: all 0.2s ease;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      white-space: nowrap;
    }
    .btn-outline:hover {
      background: rgba(78,110,242,0.04);
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: transparent;
      border: none;
    }
    .hamburger span {
      display: block;
      width: 24px;
      height: 2px;
      background: var(--text);
      border-radius: 2px;
      transition: 0.25s;
    }

    /* Hero */
    #hero {
      padding: 60px 0 40px;
      background: var(--white);
      margin-bottom: 40px;
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 40px;
      align-items: center;
    }
    .hero-title {
      font-size: 36px;
      font-weight: 700;
      line-height: 1.3;
      color: var(--text);
      margin-bottom: 16px;
    }
    .hero-subtitle {
      font-size: 16px;
      color: var(--text-secondary);
      margin-bottom: 28px;
      max-width: 90%;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .hero-visual {
      background: #E8ECF1;
      border-radius: var(--radius-card);
      height: 320px;
      display: flex;
      align-items: center;
      justify-content: center;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      position: relative;
      overflow: hidden;
    }
    .metrics-inline {
      display: flex;
      gap: 24px;
      margin-top: 24px;
    }
    .metric-small {
      background: var(--white);
      padding: 12px 16px;
      border-radius: 10px;
      box-shadow: var(--shadow-card);
      text-align: center;
      min-width: 90px;
    }
    .metric-num {
      font-size: 22px;
      font-weight: 700;
      color: var(--text);
    }
    .metric-label {
      font-size: 13px;
      color: var(--text-secondary);
    }
    .trend-up { color: var(--green); }
    .trend-down { color: var(--red); }

    /* 通用区块 */
    section {
      padding: var(--gap-section) 0;
    }
    .section-title {
      font-size: 28px;
      font-weight: 600;
      margin-bottom: 16px;
      color: var(--text);
    }
    .section-subtitle {
      font-size: 16px;
      color: var(--text-secondary);
      margin-bottom: 40px;
    }

    /* 卡片网格 */
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .card {
      background: var(--white);
      border-radius: var(--radius-card);
      padding: 28px 24px;
      box-shadow: var(--shadow-card);
      transition: all 0.25s ease;
    }
    .card:hover {
      box-shadow: var(--shadow-card-hover);
      transform: translateY(-2px);
    }
    .card-icon {
      font-size: 40px;
      color: var(--primary);
      margin-bottom: 16px;
      line-height: 1;
    }
    .card-title {
      font-size: 20px;
      font-weight: 600;
      margin-bottom: 10px;
    }
    .card-desc {
      font-size: 14px;
      color: var(--text-secondary);
      line-height: 1.6;
    }

    /* 指标看板 */
    #metrics {
      background: #F0F2F8;
      border-radius: 20px;
      margin: 0 24px;
      padding: 48px 24px;
    }
    .metrics-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
      text-align: center;
    }
    .big-number {
      font-size: 32px;
      font-weight: 700;
      color: var(--primary);
    }

    /* 服务矩阵 */
    .grid-2x2 {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 24px;
    }

    /* 对比 */
    .comparison-row {
      display: grid;
      grid-template-columns: 1fr 60px 1fr;
      align-items: center;
      gap: 20px;
    }
    .compare-card {
      background: var(--white);
      border-radius: var(--radius-card);
      padding: 28px;
      box-shadow: var(--shadow-card);
    }
    .compare-card.low {
      background: #FFF5F5;
      border-left: 4px solid var(--red);
    }
    .compare-card.high {
      background: #F0FFF6;
      border-left: 4px solid var(--green);
    }
    .vs-badge {
      font-weight: 700;
      font-size: 18px;
      color: var(--text-secondary);
      text-align: center;
    }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 18px 0;
      cursor: pointer;
    }
    .faq-question {
      font-weight: 600;
      font-size: 18px;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-secondary);
      font-size: 16px;
      line-height: 1.6;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
    }
    .faq-icon {
      font-size: 24px;
      transition: transform 0.3s;
    }
    .faq-item.open .faq-icon {
      transform: rotate(45deg);
    }

    /* CTA */
    #cta {
      background: #F0F4FF;
      border-radius: 20px;
      margin: 40px 24px;
      padding: 48px 24px;
      text-align: center;
    }
    .cta-form {
      display: flex;
      flex-wrap: wrap;
      gap: 16px;
      justify-content: center;
      margin-top: 28px;
    }
    .cta-form input,
    .cta-form textarea {
      padding: 12px 16px;
      border: 1px solid var(--border-input);
      border-radius: var(--radius-input);
      font-size: 15px;
      background: white;
      transition: 0.2s;
      min-width: 200px;
    }
    .cta-form input:focus,
    .cta-form textarea:focus {
      outline: none;
      border-color: var(--primary);
      box-shadow: 0 0 0 3px rgba(78,110,242,0.15);
    }
    .btn-submit {
      background: var(--primary);
      color: white;
      border: none;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      cursor: pointer;
    }

    /* Footer */
    #footer {
      background: #1F2329;
      color: #86909C;
      padding: 48px 0 24px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr;
      gap: 30px;
    }
    .footer-links a {
      display: block;
      color: #FFFFFF;
      margin-bottom: 8px;
    }

    @media (max-width: 1024px) {
      .hero-grid { grid-template-columns: 1fr; }
      .grid-3 { grid-template-columns: repeat(2,1fr); }
      .comparison-row { grid-template-columns: 1fr; }
      .vs-badge { margin: 12px 0; }
    }
    @media (max-width: 768px) {
      .hamburger { display: flex; }
      .nav-menu {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 64px;
        left: 0;
        width: 100%;
        background: white;
        padding: 24px;
        box-shadow: 0 8px 20px rgba(0,0,0,0.08);
      }
      .nav-menu.open { display: flex; }
      .grid-2x2, .grid-3 { grid-template-columns: 1fr; }
      .metrics-grid { grid-template-columns: repeat(2,1fr); }
      .hero-title { font-size: 28px; }
      .container { padding: 0 16px; }
    }