/* roulang page: index */
:root {
      --primary: #0A0E27;
      --accent: #00F0FF;
      --highlight: #BD00FF;
      --bg: #FAFAFC;
      --card-bg: #FFFFFF;
      --dark-bg: #0D1025;
      --text-primary: #0A0E27;
      --text-body: #4A4A5A;
      --text-muted: #8E8E9A;
      --border: #E8E8F0;
      --radius-card: 12px;
      --radius-btn: 8px;
      --shadow-card: 0 1px 3px rgba(10,14,39,0.06), 0 1px 2px rgba(10,14,39,0.04);
      --shadow-hover: 0 8px 24px rgba(10,14,39,0.12), 0 2px 8px rgba(0,240,255,0.08);
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", system-ui, sans-serif;
      --font-mono: "Inter", "SF Mono", "JetBrains Mono", monospace;
    }
    * {
      box-sizing: border-box;
    }
    body {
      margin: 0;
      font-family: var(--font-sans);
      background-color: var(--bg);
      color: var(--text-body);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }
    h1, h2, h3, h4, h5, h6 {
      color: var(--text-primary);
      font-weight: 700;
      letter-spacing: -0.3px;
    }
    a {
      color: inherit;
      text-decoration: none;
      transition: color 0.2s;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    .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 */
    .nav-header {
      position: sticky;
      top: 0;
      z-index: 50;
      background: rgba(250,250,252,0.85);
      backdrop-filter: blur(8px);
      height: 64px;
      display: flex;
      align-items: center;
      border-bottom: 1px solid var(--border);
    }
    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 700;
      font-size: 20px;
      color: var(--primary);
      letter-spacing: -0.2px;
    }
    .logo-icon {
      width: 28px;
      height: 28px;
      background: linear-gradient(135deg, var(--accent), var(--highlight));
      border-radius: 6px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-size: 16px;
    }
    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
    }
    .nav-links a {
      font-size: 15px;
      font-weight: 500;
      color: var(--text-body);
      position: relative;
      padding-bottom: 4px;
    }
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--accent);
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 10%;
      width: 0;
      height: 2px;
      background: var(--accent);
      box-shadow: 0 0 6px var(--accent);
      transition: width 0.2s ease;
    }
    .nav-links a.active::after,
    .nav-links a:hover::after {
      width: 80%;
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 6px;
      cursor: pointer;
      background: none;
      border: none;
      padding: 4px;
    }
    .hamburger span {
      display: block;
      width: 24px;
      height: 2px;
      background: var(--primary);
      transition: 0.2s;
    }
    .mobile-menu {
      display: none;
      position: fixed;
      top: 64px;
      left: 0;
      width: 100%;
      height: calc(100vh - 64px);
      background: rgba(10,14,39,0.92);
      backdrop-filter: blur(12px);
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 36px;
      z-index: 40;
      transform: translateX(100%);
      transition: transform 0.3s ease;
    }
    .mobile-menu.open {
      transform: translateX(0);
    }
    .mobile-menu a {
      font-size: 24px;
      color: white;
      font-weight: 600;
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .mobile-menu { display: flex; }
    }
    /* 按钮 */
    .btn-primary {
      background: var(--accent);
      color: var(--primary);
      font-weight: 600;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      display: inline-block;
      transition: all 0.2s;
      box-shadow: 0 0 12px rgba(0,240,255,0.3);
      border: none;
      cursor: pointer;
    }
    .btn-primary:hover {
      background: #33F3FF;
      transform: scale(1.03);
      box-shadow: 0 0 20px rgba(0,240,255,0.5);
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--accent);
      color: var(--accent);
      font-weight: 600;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      display: inline-block;
      transition: all 0.2s;
    }
    .btn-outline:hover {
      background: rgba(0,240,255,0.1);
    }
    /* 区块间距 */
    section {
      padding-top: 100px;
      padding-bottom: 100px;
    }
    @media (max-width: 768px) {
      section {
        padding-top: 60px;
        padding-bottom: 60px;
      }
    }
    .section-title {
      font-size: 36px;
      line-height: 1.3;
      margin-bottom: 16px;
      color: var(--primary);
      font-weight: 700;
    }
    @media (max-width: 768px) {
      .section-title { font-size: 28px; }
    }
    .card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      transition: box-shadow 0.25s ease, transform 0.2s;
      overflow: hidden;
    }
    .card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-2px);
    }
    .glow-border {
      border: 1px solid var(--border);
      transition: border-color 0.2s;
    }
    .glow-border:hover {
      border-color: var(--accent);
      box-shadow: 0 0 12px rgba(0,240,255,0.15);
    }
    .faq-item {
      border-bottom: 1px solid var(--border);
      padding: 20px 0;
      cursor: pointer;
    }
    .faq-question {
      display: flex;
      align-items: center;
      gap: 12px;
      font-weight: 600;
      color: var(--text-primary);
    }
    .faq-indicator {
      width: 3px;
      height: 20px;
      background: var(--accent);
      transition: height 0.3s, background 0.2s;
    }
    .faq-item.active .faq-indicator {
      height: 40px;
      background: var(--highlight);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      padding-left: 24px;
      color: var(--text-body);
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
    }
    footer {
      background: var(--dark-bg);
      color: #B0B0C0;
      padding: 60px 0 30px;
    }