/* roulang page: index */
:root {
      --primary: #1A5FDC;
      --primary-dark: #0F3B8C;
      --accent: #F97316;
      --bg: #F8FAFC;
      --card: #FFFFFF;
      --text: #0F172A;
      --text-secondary: #475569;
      --text-muted: #94A3B8;
      --success: #10B981;
      --border: #E2E8F0;
      --shadow-sm: 0 1px 3px rgba(0,0,0,0.04), 0 4px 12px rgba(0,0,0,0.06);
      --shadow-hover: 0 8px 24px rgba(26,95,220,0.12);
      --radius-card: 12px;
      --radius-btn: 8px;
      --font-sans: 'Inter', 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
      --transition: 0.2s ease;
    }
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: var(--font-sans);
      background: var(--bg);
      color: var(--text);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }
    img { max-width: 100%; height: auto; display: block; }
    a { text-decoration: none; color: inherit; transition: var(--transition); }
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }
    /* 导航 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      background: transparent;
      transition: background 0.3s, box-shadow 0.3s;
      padding: 16px 0;
    }
    .header.scrolled {
      background: #fff;
      box-shadow: 0 4px 20px rgba(0,0,0,0.04);
      padding: 12px 0;
    }
    .header .container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      flex-wrap: wrap;
    }
    .logo {
      font-size: 24px;
      font-weight: 700;
      color: #fff;
      letter-spacing: 0.5px;
      display: flex;
      align-items: center;
      gap: 8px;
      transition: color 0.3s;
    }
    .header.scrolled .logo { color: var(--text); }
    .logo-icon {
      width: 32px;
      height: 32px;
      background: var(--accent);
      border-radius: 8px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: #fff;
      font-weight: bold;
      font-size: 18px;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
      list-style: none;
    }
    .nav-links a {
      font-size: 15px;
      font-weight: 500;
      color: rgba(255,255,255,0.9);
      position: relative;
      padding: 4px 0;
    }
    .header.scrolled .nav-links a { color: var(--text-secondary); }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: -2px;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--primary);
      transition: width 0.2s;
    }
    .nav-links a:hover::after,
    .nav-links a.active::after { width: 100%; }
    .nav-links a:hover { color: #fff; }
    .header.scrolled .nav-links a:hover { color: var(--primary); }
    .btn-primary {
      background: var(--accent);
      color: #fff;
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 15px;
      border: none;
      cursor: pointer;
      transition: background 0.2s, transform 0.2s;
      display: inline-block;
    }
    .btn-primary:hover { background: #e8670f; transform: scale(1.02); }
    .btn-secondary {
      background: transparent;
      border: 1px solid var(--primary);
      color: var(--primary);
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 15px;
      transition: 0.2s;
    }
    .btn-secondary:hover { background: rgba(26,95,220,0.05); }
    .btn-ghost {
      background: transparent;
      border: 1px solid rgba(255,255,255,0.6);
      color: #fff;
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 15px;
    }
    .btn-ghost:hover { background: #fff; color: var(--primary-dark); }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: none;
      border: none;
      padding: 8px;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: #fff;
      transition: 0.3s;
    }
    .header.scrolled .hamburger span { background: var(--text); }
    @media (max-width: 1024px) {
      .nav-links { gap: 20px; }
    }
    @media (max-width: 768px) {
      .hamburger { display: flex; }
      .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background: #fff;
        flex-direction: column;
        padding: 24px;
        box-shadow: 0 12px 24px rgba(0,0,0,0.08);
        gap: 16px;
      }
      .nav-links.active { display: flex; }
      .nav-links a { color: var(--text) !important; }
      .header.scrolled .nav-links a { color: var(--text) !important; }
    }
    /* Hero */
    .hero {
      padding: 160px 0 100px;
      background: linear-gradient(135deg, #F8FAFC 0%, #E8F0FE 100%);
      position: relative;
      overflow: hidden;
    }
    .hero .container {
      display: flex;
      align-items: center;
      gap: 60px;
    }
    .hero-content { flex: 1; }
    .hero h1 {
      font-size: 42px;
      font-weight: 700;
      line-height: 1.2;
      letter-spacing: -0.5px;
      margin-bottom: 20px;
      color: #0F172A;
    }
    .hero-sub {
      font-size: 18px;
      color: var(--text-secondary);
      margin-bottom: 32px;
      max-width: 480px;
    }
    .hero-buttons { display: flex; gap: 16px; flex-wrap: wrap; }
    .hero-image {
      flex: 1;
      display: flex;
      justify-content: center;
      align-items: center;
    }
    .hero-image img {
      max-height: 360px;
      border-radius: 24px;
      box-shadow: 0 20px 40px rgba(26,95,220,0.15);
    }
    @media (max-width: 768px) {
      .hero .container { flex-direction: column; text-align: center; }
      .hero h1 { font-size: 32px; }
      .hero-sub { margin-left: auto; margin-right: auto; }
      .hero-buttons { justify-content: center; }
      .hero-image { order: -1; margin-bottom: 24px; }
    }
    /* 板块通用 */
    section { padding: 80px 0; }
    @media (max-width: 768px) { section { padding: 48px 0; } }
    .section-title {
      font-size: 28px;
      font-weight: 600;
      margin-bottom: 16px;
      text-align: center;
    }
    .section-desc {
      text-align: center;
      color: var(--text-secondary);
      max-width: 600px;
      margin: 0 auto 48px;
      font-size: 17px;
    }
    /* 卡片网格 */
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .grid-2 {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 24px;
    }
    @media (max-width: 1024px) {
      .grid-3 { grid-template-columns: repeat(2, 1fr); }
      .grid-2 { grid-template-columns: 1fr; }
    }
    @media (max-width: 640px) {
      .grid-3, .grid-2 { grid-template-columns: 1fr; }
    }
    .card {
      background: var(--card);
      border-radius: var(--radius-card);
      padding: 28px;
      box-shadow: var(--shadow-sm);
      transition: transform 0.2s, box-shadow 0.2s;
      border: 1px solid var(--border);
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .icon-circle {
      width: 48px;
      height: 48px;
      background: rgba(249,115,22,0.1);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
      color: var(--accent);
      font-size: 22px;
    }
    .card h3 { font-size: 20px; margin-bottom: 12px; }
    .card p { color: var(--text-secondary); font-size: 16px; }
    /* 场景卡片 */
    .scene-card {
      display: flex;
      align-items: center;
      gap: 24px;
      background: var(--card);
      border-radius: var(--radius-card);
      padding: 24px;
      box-shadow: var(--shadow-sm);
      border-left: 4px solid var(--primary);
      transition: 0.2s;
    }
    .scene-card:hover { box-shadow: var(--shadow-hover); }
    .scene-img {
      width: 80px;
      height: 80px;
      border-radius: 12px;
      object-fit: cover;
      background: #f1f5f9;
    }
    /* 案例卡片 */
    .case-card {
      background: var(--card);
      border-radius: var(--radius-card);
      padding: 24px;
      box-shadow: var(--shadow-sm);
    }
    .case-meta { display: flex; justify-content: space-between; align-items: center; margin-bottom: 16px; }
    .case-tag {
      background: #E8F0FE;
      color: var(--primary-dark);
      padding: 4px 12px;
      border-radius: 20px;
      font-size: 13px;
      font-weight: 500;
    }
    .case-number {
      font-size: 32px;
      font-weight: 700;
      color: var(--accent);
    }
    .case-quote { font-style: italic; color: var(--text-secondary); margin: 12px 0; }
    /* FAQ */
    .faq-group { margin-bottom: 32px; }
    .faq-group-title {
      font-size: 14px;
      color: var(--text-muted);
      margin-bottom: 16px;
      padding-bottom: 8px;
      border-bottom: 1px solid var(--border);
    }
    .faq-item {
      background: var(--card);
      border-radius: var(--radius-card);
      margin-bottom: 12px;
      box-shadow: var(--shadow-sm);
    }
    .faq-question {
      width: 100%;
      text-align: left;
      padding: 18px 24px;
      font-weight: 600;
      font-size: 17px;
      background: none;
      border: none;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
    }
    .faq-answer {
      padding: 0 24px 20px;
      color: var(--text-secondary);
      display: none;
    }
    .faq-item.open .faq-answer { display: block; }
    .faq-item.open .faq-icon { transform: rotate(45deg); }
    /* CTA 横幅 */
    .cta-band {
      background: var(--primary-dark);
      padding: 80px 0;
      text-align: center;
      color: #fff;
    }
    .cta-band h2 { font-size: 32px; margin-bottom: 16px; }
    .cta-band p { opacity: 0.8; margin-bottom: 32px; font-size: 18px; }
    /* 页脚 */
    .footer {
      background: #fff;
      padding: 60px 0 0;
      border-top: 1px solid var(--border);
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
      margin-bottom: 40px;
    }
    @media (max-width: 768px) {
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }
    .footer-bottom {
      border-top: 1px solid var(--border);
      padding: 20px 0;
      text-align: center;
      color: var(--text-muted);
      font-size: 14px;
    }