/* roulang page: index */
:root {
      --primary: #4E6EF2;
      --primary-light: #6C5CE7;
      --primary-soft: #EEF1FE;
      --green: #00B578;
      --orange: #FF9F0A;
      --red: #FA5151;
      --bg: #F5F6FA;
      --white: #FFFFFF;
      --text-dark: #1F2329;
      --text-mid: #86909C;
      --border-light: #E5E8EF;
      --radius-lg: 12px;
      --radius-md: 8px;
      --shadow-card: 0 2px 12px rgba(0,0,0,0.04);
      --shadow-hover: 0 4px 20px rgba(0,0,0,0.08);
      --transition: 200ms ease;
    }

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

    body {
      font-family: -apple-system, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      background-color: var(--bg);
      color: var(--text-dark);
      line-height: 1.6;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
      scroll-behavior: smooth;
    }

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

    a {
      text-decoration: none;
      color: inherit;
    }

    button, input {
      font-family: inherit;
    }

    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }

    /* 导航栏 PC */
    .navbar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 64px;
      background: rgba(255,255,255,0.85);
      backdrop-filter: blur(10px);
      -webkit-backdrop-filter: blur(10px);
      box-shadow: 0 1px 4px rgba(0,0,0,0.02);
      z-index: 50;
      display: flex;
      align-items: center;
      justify-content: center;
    }
    .nav-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      max-width: 1200px;
      padding: 0 24px;
    }
    .logo {
      font-weight: 700;
      font-size: 22px;
      color: var(--primary);
      letter-spacing: 0.5px;
      display: flex;
      align-items: center;
      gap: 6px;
    }
    .logo i {
      font-size: 24px;
      color: var(--primary-light);
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 6px;
      background: var(--bg);
      border-radius: 40px;
      padding: 4px;
    }
    .nav-links a {
      padding: 8px 18px;
      border-radius: 30px;
      font-size: 15px;
      font-weight: 500;
      color: var(--text-mid);
      transition: all var(--transition);
    }
    .nav-links a.active, .nav-links a:hover {
      background: var(--primary);
      color: white;
      box-shadow: 0 2px 8px rgba(78,110,242,0.3);
    }
    .btn-primary-sm {
      background: var(--primary);
      color: white;
      border: none;
      border-radius: 30px;
      padding: 10px 22px;
      font-weight: 600;
      font-size: 15px;
      cursor: pointer;
      transition: all var(--transition);
      display: inline-flex;
      align-items: center;
      gap: 6px;
    }
    .btn-primary-sm:hover {
      filter: brightness(0.92);
      box-shadow: 0 4px 12px rgba(78,110,242,0.35);
      transform: translateY(-1px);
    }
    .mobile-menu-btn {
      display: none;
      font-size: 24px;
      color: var(--primary);
      background: none;
      border: none;
    }

    /* 移动端底部导航 */
    .mobile-nav {
      display: none;
      position: fixed;
      bottom: 0;
      left: 0;
      width: 100%;
      background: rgba(255,255,255,0.95);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      box-shadow: 0 -2px 12px rgba(0,0,0,0.04);
      z-index: 50;
      padding: 8px 16px;
      justify-content: space-around;
      align-items: center;
    }
    .mobile-nav a {
      display: flex;
      flex-direction: column;
      align-items: center;
      font-size: 12px;
      color: var(--text-mid);
      gap: 4px;
      padding: 4px 8px;
      border-radius: 20px;
      transition: all var(--transition);
    }
    .mobile-nav a i {
      font-size: 20px;
    }
    .mobile-nav a.active {
      color: var(--primary);
      background: var(--primary-soft);
    }

    /* 板块通用 */
    section {
      padding: 80px 0;
    }
    .section-title {
      font-size: 28px;
      font-weight: 700;
      margin-bottom: 16px;
      color: var(--text-dark);
    }
    .section-desc {
      font-size: 16px;
      color: var(--text-mid);
      max-width: 700px;
      margin: 0 auto 40px;
    }

    /* 卡片 */
    .card {
      background: var(--white);
      border-radius: var(--radius-lg);
      padding: 28px 24px;
      box-shadow: var(--shadow-card);
      transition: all var(--transition);
    }
    .card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-2px);
    }

    /* 按钮 */
    .btn-primary {
      background: var(--primary);
      color: white;
      border: none;
      border-radius: var(--radius-md);
      padding: 12px 28px;
      font-weight: 600;
      font-size: 16px;
      cursor: pointer;
      transition: all var(--transition);
      display: inline-flex;
      align-items: center;
      gap: 8px;
    }
    .btn-primary:hover {
      filter: brightness(0.92);
      box-shadow: 0 6px 16px rgba(78,110,242,0.4);
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--primary);
      color: var(--primary);
      border-radius: var(--radius-md);
      padding: 12px 28px;
      font-weight: 600;
      font-size: 16px;
      cursor: pointer;
      transition: all var(--transition);
    }
    .btn-outline:hover {
      background: var(--primary-soft);
    }

    /* FAQ 手风琴 */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 16px 0;
    }
    .faq-question {
      font-weight: 500;
      font-size: 16px;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, padding 0.3s ease;
      color: var(--text-mid);
      font-size: 15px;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      padding-top: 12px;
    }
    .faq-item.open .faq-icon {
      transform: rotate(180deg);
    }

    @media (max-width: 768px) {
      .navbar {
        display: none;
      }
      .mobile-nav {
        display: flex;
      }
      section {
        padding: 60px 0;
      }
      .section-title {
        font-size: 22px;
      }
      .mobile-menu-btn {
        display: block;
      }
      .hero-title {
        font-size: 28px !important;
      }
    }
    @media (min-width: 769px) {
      .mobile-nav {
        display: none;
      }
    }