/* roulang page: index */
:root {
      --deep-black-blue: #0A0E17;
      --card-dark: #1C2333;
      --accent-red: #E63946;
      --accent-red-hover: #C1121F;
      --clean-white: #F1FAEE;
      --text-body: #8A94A6;
      --text-muted: #B0B8C5;
      --border-light: rgba(241, 250, 238, 0.06);
      --border-hover: rgba(241, 250, 238, 0.15);
      --shadow-card: 0 8px 24px rgba(0,0,0,0.3);
      --transition-smooth: all 0.3s ease;
    }
    * {
      box-sizing: border-box;
    }
    body {
      font-family: 'Inter', 'Noto Sans SC', system-ui, -apple-system, sans-serif;
      background-color: var(--deep-black-blue);
      color: var(--text-body);
      line-height: 1.6;
      margin: 0;
      -webkit-font-smoothing: antialiased;
      scroll-behavior: smooth;
    }
    .container {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.5rem;
      padding-right: 1.5rem;
    }
    @media (min-width: 768px) {
      .container {
        padding-left: 2rem;
        padding-right: 2rem;
      }
    }
    /* 导航栏 */
    .navbar {
      position: sticky;
      top: 0;
      z-index: 50;
      background-color: rgba(10, 14, 23, 0.92);
      backdrop-filter: blur(6px);
      border-bottom: 1px solid rgba(241, 250, 238, 0.05);
      transition: background-color 0.3s;
    }
    .nav-link {
      color: var(--text-muted);
      font-weight: 500;
      transition: color 0.2s;
      position: relative;
      padding-bottom: 2px;
      text-decoration: none;
    }
    .nav-link:hover {
      color: var(--clean-white);
    }
    .nav-link.active {
      color: var(--clean-white);
    }
    .nav-link.active::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 100%;
      height: 2px;
      background-color: var(--accent-red);
      border-radius: 2px;
    }
    .btn-primary {
      background-color: var(--accent-red);
      color: var(--clean-white);
      font-weight: 600;
      border-radius: 0.5rem;
      padding: 0.75rem 1.75rem;
      transition: all 0.2s ease;
      display: inline-block;
      text-align: center;
      border: none;
      cursor: pointer;
      text-decoration: none;
      letter-spacing: 0.02em;
    }
    .btn-primary:hover {
      background-color: var(--accent-red-hover);
      box-shadow: 0 8px 20px rgba(230, 57, 70, 0.25);
      transform: scale(1.03);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--clean-white);
      color: var(--clean-white);
      font-weight: 600;
      border-radius: 0.5rem;
      padding: 0.75rem 1.75rem;
      transition: all 0.2s ease;
      display: inline-block;
      text-align: center;
      cursor: pointer;
      text-decoration: none;
    }
    .btn-outline:hover {
      background-color: var(--clean-white);
      color: var(--deep-black-blue);
    }
    .card {
      background-color: var(--card-dark);
      border: 1px solid var(--border-light);
      border-radius: 1rem;
      padding: 2rem;
      transition: var(--transition-smooth);
      box-shadow: 0 4px 12px rgba(0,0,0,0.25);
      height: 100%;
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: 0 16px 32px rgba(0,0,0,0.5);
      border-color: var(--border-hover);
    }
    .card-accent {
      border-left: 4px solid var(--accent-red);
      background-color: #1E2535;
    }
    .section-padding {
      padding-top: 5rem;
      padding-bottom: 5rem;
    }
    @media (min-width: 768px) {
      .section-padding {
        padding-top: 7rem;
        padding-bottom: 7rem;
      }
    }
    .text-gradient {
      background: linear-gradient(135deg, #F1FAEE 0%, #E63946 80%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }
    .data-number {
      font-family: 'Inter', monospace;
      font-weight: 700;
      color: var(--clean-white);
    }
    /* 表单样式 */
    input, textarea {
      background-color: var(--card-dark);
      border: 1px solid var(--text-body);
      color: var(--clean-white);
      border-radius: 0.5rem;
      padding: 0.75rem 1rem;
      width: 100%;
      transition: border 0.2s;
      font-family: inherit;
    }
    input:focus, textarea:focus {
      outline: none;
      border-color: var(--accent-red);
      box-shadow: 0 0 0 2px rgba(230,57,70,0.3);
    }
    .faq-item {
      border-bottom: 1px solid var(--card-dark);
      transition: background 0.2s;
    }
    .faq-item.active {
      background-color: rgba(28, 35, 51, 0.5);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, padding 0.3s;
    }
    .faq-item.active .faq-answer {
      max-height: 300px;
      padding-top: 0.75rem;
      padding-bottom: 1rem;
    }
    .arrow-icon {
      transition: transform 0.2s;
    }
    .faq-item.active .arrow-icon {
      transform: rotate(180deg);
    }
    /* 移动端菜单 */
    .mobile-menu {
      display: none;
    }
    @media (max-width: 767px) {
      .desktop-nav {
        display: none;
      }
      .mobile-menu {
        display: block;
      }
    }