/* roulang page: index */
:root {
      --primary: #0A1F3F;
      --primary-light: #1A3A5C;
      --accent-red: #E63946;
      --accent-gold: #F4A261;
      --bg-light: #F8FAFC;
      --card-bg: #FFFFFF;
      --text-main: #1E293B;
      --text-muted: #64748B;
      --border-light: #E2E8F0;
      --radius-card: 16px;
      --radius-btn: 999px;
      --shadow-card: 0 4px 14px rgba(0,0,0,0.04);
      --shadow-hover: 0 12px 28px rgba(0,0,0,0.08);
      --font-sans: 'Inter', system-ui, -apple-system, 'Noto Sans SC', sans-serif;
      --transition: all 0.25s ease;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--bg-light);
      color: var(--text-main);
      line-height: 1.7;
      -webkit-font-smoothing: antialiased;
    }

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

    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition);
    }

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

    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }

    /* 导航 */
    .navbar {
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(8px);
      border-bottom: 1px solid rgba(0,0,0,0.04);
      position: sticky;
      top: 0;
      z-index: 50;
      padding: 0 24px;
    }
    .nav-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 70px;
    }
    .logo-text {
      font-size: 24px;
      font-weight: 800;
      color: var(--primary);
      letter-spacing: -0.5px;
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .logo-icon {
      width: 28px;
      height: 28px;
      background: var(--accent-red);
      border-radius: 6px;
      position: relative;
    }
    .logo-icon::after {
      content: "";
      position: absolute;
      top: 6px;
      left: 6px;
      width: 16px;
      height: 16px;
      background: white;
      border-radius: 4px;
      clip-path: polygon(50% 0%, 100% 50%, 50% 100%, 0% 50%);
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-links a {
      font-size: 16px;
      font-weight: 500;
      color: #334155;
      position: relative;
      padding: 8px 0;
    }
    .nav-links a:hover {
      color: var(--accent-red);
    }
    .nav-links a.active {
      color: var(--accent-red);
    }
    .nav-links a.active::after {
      content: "";
      position: absolute;
      bottom: 0;
      left: 0;
      width: 100%;
      height: 3px;
      background: var(--accent-red);
      border-radius: 2px;
    }
    .nav-cta {
      background: var(--accent-red);
      color: white;
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 15px;
      white-space: nowrap;
      transition: var(--transition);
    }
    .nav-cta:hover {
      background: #C1121F;
    }

    /* 汉堡菜单 */
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: none;
      border: none;
    }
    .hamburger span {
      width: 26px;
      height: 2.5px;
      background: var(--primary);
      border-radius: 4px;
      transition: var(--transition);
    }
    .mobile-menu {
      display: none;
      flex-direction: column;
      background: white;
      padding: 20px;
      border-top: 1px solid var(--border-light);
    }

    /* 区块间距 */
    section {
      padding: 80px 0;
    }
    @media (max-width: 768px) {
      section {
        padding: 56px 0;
      }
    }

    /* 标题 */
    h1 {
      font-size: 42px;
      font-weight: 700;
      letter-spacing: -0.5px;
      line-height: 1.2;
    }
    h2 {
      font-size: 32px;
      font-weight: 700;
      letter-spacing: -0.3px;
    }
    h3 {
      font-size: 20px;
      font-weight: 600;
    }

    /* 卡片 */
    .card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      padding: 28px;
      transition: var(--transition);
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
      border-top: 3px solid var(--accent-red);
    }

    /* 按钮 */
    .btn-primary {
      background: var(--accent-red);
      color: white;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      display: inline-block;
      transition: var(--transition);
      border: none;
      cursor: pointer;
    }
    .btn-primary:hover {
      background: #C1121F;
    }
    .btn-outline {
      background: transparent;
      border: 2px solid white;
      color: white;
      padding: 12px 30px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: var(--transition);
    }
    .btn-outline:hover {
      background: white;
      color: var(--primary);
    }

    /* 数据徽章 */
    .stat-badge {
      font-size: 28px;
      font-weight: 800;
      color: var(--accent-red);
    }

    /* FAQ 手风琴 */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
    }
    .faq-question {
      width: 100%;
      background: none;
      border: none;
      text-align: left;
      font-size: 18px;
      font-weight: 600;
      padding: 20px 0;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease;
      background: #f9fafb;
      padding: 0 16px;
      border-radius: 10px;
      margin-bottom: 8px;
    }
    .faq-answer.open {
      max-height: 300px;
      padding: 16px;
    }

    /* 表单 */
    .input-field {
      width: 100%;
      padding: 14px 16px;
      border: 1px solid var(--border-light);
      border-radius: 10px;
      font-size: 16px;
      transition: var(--transition);
      background: white;
    }
    .input-field:focus {
      outline: none;
      border-color: var(--accent-red);
      box-shadow: 0 0 0 3px rgba(230,57,70,0.15);
    }

    /* 页脚 */
    .footer-links a:hover {
      color: var(--accent-red);
    }

    @media (max-width: 1024px) {
      .nav-links {
        gap: 20px;
      }
    }
    @media (max-width: 768px) {
      .nav-links, .nav-cta.desktop {
        display: none;
      }
      .hamburger {
        display: flex;
      }
      .mobile-menu.show {
        display: flex;
      }
      h1 {
        font-size: 32px;
      }
      h2 {
        font-size: 28px;
      }
      .stat-badge {
        font-size: 24px;
      }
      .grid-3, .grid-4 {
        grid-template-columns: 1fr;
      }
    }