/* roulang page: index */
:root {
      --primary: #4E6EF2;
      --primary-dark: #3D5BD9;
      --secondary: #00B578;
      --accent: #FF9F0A;
      --danger: #FA5151;
      --text: #1F2329;
      --text-gray: #86909C;
      --bg: #F5F6FA;
      --card: #FFFFFF;
      --border: #E5E8EF;
      --radius-lg: 12px;
      --radius-md: 8px;
      --shadow-sm: 0 2px 12px rgba(0,0,0,0.06);
      --shadow-hover: 0 8px 24px rgba(0,0,0,0.1);
      --focus-glow: 0 0 0 3px rgba(78,110,242,0.25);
    }
    * {
      box-sizing: border-box;
    }
    body {
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
      background-color: var(--bg);
      color: var(--text);
      line-height: 1.5;
      margin: 0;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
    }
    .container {
      max-width: 1200px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 24px;
      padding-right: 24px;
    }
    @media (max-width: 768px) {
      .container {
        padding-left: 16px;
        padding-right: 16px;
      }
    }
    /* 导航 */
    .navbar {
      position: sticky;
      top: 0;
      z-index: 50;
      background: white;
      height: 64px;
      border-bottom: 1px solid transparent;
      transition: box-shadow 0.2s ease;
      box-shadow: 0 2px 8px rgba(0,0,0,0.02);
    }
    .navbar.scrolled {
      box-shadow: 0 4px 16px rgba(0,0,0,0.05);
    }
    .nav-link {
      position: relative;
      font-weight: 500;
      color: var(--text);
      transition: color 0.2s;
      text-decoration: none;
      font-size: 1rem;
    }
    .nav-link:hover {
      color: var(--primary);
    }
    .nav-link.active {
      color: var(--primary);
    }
    .nav-link.active::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      right: 0;
      height: 2px;
      background: var(--primary);
      border-radius: 2px;
    }
    .hamburger {
      display: none;
      background: none;
      border: none;
      cursor: pointer;
      padding: 8px;
    }
    @media (max-width: 768px) {
      .hamburger {
        display: block;
      }
      .nav-menu {
        display: none;
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100vh;
        background: white;
        flex-direction: column;
        padding: 80px 24px 40px;
        z-index: 40;
        align-items: flex-start;
        gap: 24px;
        overflow-y: auto;
      }
      .nav-menu.open {
        display: flex;
      }
      .navbar {
        height: 56px;
      }
    }
    /* hero */
    .hero-gradient {
      background: linear-gradient(135deg, #4E6EF2 0%, #A8BFFF 100%);
    }
    /* 卡片悬停 */
    .card-hover {
      transition: all 200ms ease-out;
    }
    .card-hover:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-2px);
    }
    /* FAQ 箭头 */
    .faq-item summary {
      list-style: none;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      padding: 16px 0;
      font-weight: 500;
      border-bottom: 1px solid var(--border);
      color: var(--text);
      transition: color 0.2s;
    }
    .faq-item summary::-webkit-details-marker {
      display: none;
    }
    .faq-item summary .arrow {
      transition: transform 0.2s;
      font-size: 1.2rem;
      color: var(--text-gray);
    }
    .faq-item[open] summary {
      color: var(--primary);
    }
    .faq-item[open] summary .arrow {
      transform: rotate(180deg);
      color: var(--primary);
    }
    .faq-item .answer {
      padding: 12px 0 20px;
      color: var(--text-gray);
      line-height: 1.6;
      font-size: 0.95rem;
    }
    /* 案例滚动 */
    .case-scroll {
      display: flex;
      overflow-x: auto;
      gap: 24px;
      scrollbar-width: none;
      -ms-overflow-style: none;
      padding-bottom: 8px;
    }
    .case-scroll::-webkit-scrollbar {
      display: none;
    }
    @media (max-width: 768px) {
      .case-scroll {
        gap: 16px;
        padding-left: 0;
        padding-right: 0;
      }
    }
    /* 输入框与按钮 */
    .input-field {
      border: 1px solid var(--border);
      border-radius: var(--radius-md);
      padding: 12px 16px;
      width: 100%;
      transition: border 0.2s, box-shadow 0.2s;
      background: white;
    }
    .input-field:focus {
      outline: none;
      border-color: var(--primary);
      box-shadow: var(--focus-glow);
    }
    .btn-primary {
      background-color: var(--primary);
      color: white;
      padding: 12px 28px;
      border-radius: 8px;
      font-weight: 500;
      transition: background 0.2s, box-shadow 0.2s;
      border: none;
      cursor: pointer;
      display: inline-block;
      text-align: center;
      text-decoration: none;
    }
    .btn-primary:hover {
      background-color: var(--primary-dark);
    }
    .btn-primary:focus {
      box-shadow: var(--focus-glow);
    }
    .btn-outline {
      background: transparent;
      border: 1px solid var(--primary);
      color: var(--primary);
      padding: 12px 28px;
      border-radius: 8px;
      font-weight: 500;
      transition: all 0.2s;
      cursor: pointer;
      display: inline-block;
      text-align: center;
      text-decoration: none;
    }
    .btn-outline:hover {
      background: rgba(78,110,242,0.05);
    }
    .btn-outline:focus {
      box-shadow: var(--focus-glow);
    }
    @media (max-width: 768px) {
      .btn-primary, .btn-outline {
        width: 100%;
        display: block;
      }
    }
    footer {
      background: #1F2329;
      color: #86909C;
    }