/* roulang page: index */
:root {
      --cyan: #00F0FF;
      --coral: #FF6B4A;
      --bg-deep: #0A0E17;
      --card-bg: #141B26;
      --text-mute: #8A94A6;
      --text-body: #B0B8C4;
      --border-glow: rgba(0, 240, 255, 0.25);
      --shadow-glow: 0 0 24px rgba(0, 240, 255, 0.5);
    }
    * {
      box-sizing: border-box;
    }
    body {
      margin: 0;
      font-family: 'PingFang SC', 'Microsoft YaHei', 'Inter', system-ui, -apple-system, sans-serif;
      background-color: var(--bg-deep);
      color: var(--text-body);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s, background-color 0.2s;
    }
    button, .btn {
      cursor: pointer;
      font-family: inherit;
      transition: all 0.25s ease;
      border: none;
      outline: none;
    }
    .btn:focus-visible, a:focus-visible {
      outline: 3px solid var(--cyan);
      outline-offset: 3px;
    }
    .container {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.5rem;
      padding-right: 1.5rem;
    }
    /* 导航栏 */
    .nav-blur {
      background: rgba(10, 14, 23, 0.8);
      backdrop-filter: blur(20px);
      -webkit-backdrop-filter: blur(20px);
      border-bottom: 1px solid rgba(0, 240, 255, 0.15);
    }
    .nav-link {
      color: var(--text-mute);
      font-weight: 500;
      position: relative;
    }
    .nav-link::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--cyan);
      transition: width 0.25s ease;
    }
    .nav-link:hover {
      color: var(--cyan);
    }
    .nav-link:hover::after {
      width: 100%;
    }
    /* 卡片系统 */
    .card {
      background: var(--card-bg);
      border: 1px solid rgba(0, 240, 255, 0.15);
      border-radius: 20px;
      padding: 2rem;
      transition: all 0.3s ease;
    }
    .card:hover {
      border-color: var(--cyan);
      transform: translateY(-6px);
      box-shadow: 0 20px 40px rgba(0, 240, 255, 0.2);
    }
    /* 按钮 */
    .btn-primary {
      background: var(--cyan);
      color: #0A0E17;
      font-weight: 700;
      border-radius: 12px;
      padding: 0.9rem 2.2rem;
      box-shadow: 0 4px 14px rgba(0, 240, 255, 0.4);
    }
    .btn-primary:hover {
      box-shadow: 0 0 28px rgba(0, 240, 255, 0.8);
      transform: scale(1.02);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--cyan);
      color: var(--cyan);
      font-weight: 600;
      border-radius: 12px;
      padding: 0.9rem 2.2rem;
    }
    .btn-outline:hover {
      background: rgba(0, 240, 255, 0.1);
      box-shadow: 0 0 24px rgba(0, 240, 255, 0.6);
    }
    .btn-ghost {
      background: transparent;
      color: var(--cyan);
      font-weight: 600;
      padding: 0.6rem 1.2rem;
      border-radius: 8px;
    }
    .btn-ghost:hover {
      background: rgba(0, 240, 255, 0.1);
    }
    /* 粒子动画 */
    .hero-particle {
      position: absolute;
      background: var(--cyan);
      border-radius: 50%;
      opacity: 0.2;
      animation: float 8s infinite alternate ease-in-out;
    }
    @keyframes float {
      0% { transform: translateY(0px) translateX(0px); opacity: 0.15; }
      100% { transform: translateY(-30px) translateX(20px); opacity: 0.4; }
    }
    .glow-text {
      text-shadow: 0 0 18px rgba(0, 240, 255, 0.7);
    }
    /* 斜切分割 */
    .skew-divider {
      position: relative;
      height: 3px;
      background: linear-gradient(90deg, transparent, var(--cyan), transparent);
      transform: skewY(-2deg);
      margin: 3rem 0;
    }
    /* 手风琴 */
    .faq-item {
      background: var(--card-bg);
      border: 1px solid rgba(0,240,255,0.15);
      border-radius: 12px;
      margin-bottom: 12px;
      overflow: hidden;
    }
    .faq-question {
      padding: 1.2rem 1.8rem;
      font-weight: 600;
      color: white;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease, padding 0.3s;
      color: var(--text-body);
      padding: 0 1.8rem;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding: 1rem 1.8rem 1.8rem;
    }
    .faq-item.active {
      border-color: var(--cyan);
    }
    .faq-icon {
      font-size: 1.5rem;
      transition: transform 0.3s;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }
    /* 滚动数据条 */
    .data-scroll {
      animation: scrollLeft 20s linear infinite;
    }
    @keyframes scrollLeft {
      0% { transform: translateX(0); }
      100% { transform: translateX(-50%); }
    }