/* roulang page: index */
/* 设计变量与基础重置 */
    :root {
      --deep-space: #0B0E14;
      --nebula-purple: #6C5CE7;
      --aurora-cyan: #00D2FF;
      --alert-red: #FF6B6B;
      --bg-light: #FAFAFC;
      --card-white: #FFFFFF;
      --text-primary: #1A1A2E;
      --text-secondary: #5A5A72;
      --text-muted: #9A9AB0;
      --text-on-dark: #FFFFFF;
      --text-dark-muted: #B0B0C0;
      --border-light: #E8E8F0;
      --shadow-card: 0 4px 24px rgba(0, 0, 0, 0.04);
      --shadow-card-hover: 0 12px 40px rgba(108, 92, 231, 0.12);
      --radius-card: 16px;
      --radius-button: 50px;
      --radius-input: 12px;
      --transition-smooth: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    }
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    html {
      scroll-behavior: smooth;
    }
    body {
      font-family: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      background-color: var(--bg-light);
      color: var(--text-primary);
      line-height: 1.6;
      font-weight: 400;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    .font-metrics {
      font-family: 'Inter', 'PingFang SC', 'Microsoft YaHei', sans-serif;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s ease;
    }
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }
    @media (max-width: 768px) {
      .container {
        padding: 0 16px;
      }
    }
    /* 导航 */
    .header-nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 72px;
      background: rgba(255, 255, 255, 0.85);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      z-index: 50;
      transition: background 0.3s ease, box-shadow 0.3s ease;
      border-bottom: 1px solid transparent;
    }
    .header-nav.scrolled {
      background: rgba(255, 255, 255, 0.95);
      box-shadow: 0 4px 20px rgba(0, 0, 0, 0.02);
      border-bottom: 1px solid var(--border-light);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 100%;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 8px;
      font-weight: 700;
      font-size: 1.5rem;
      color: var(--text-primary);
      letter-spacing: -0.3px;
    }
    .logo-icon {
      width: 28px;
      height: 28px;
      background: linear-gradient(135deg, var(--nebula-purple), var(--aurora-cyan));
      border-radius: 8px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-size: 16px;
      box-shadow: 0 4px 10px rgba(108,92,231,0.2);
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-link {
      font-size: 0.95rem;
      font-weight: 500;
      color: var(--text-secondary);
      position: relative;
      padding: 4px 0;
      transition: color 0.2s;
    }
    .nav-link::after {
      content: '';
      position: absolute;
      bottom: -2px;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--nebula-purple);
      transition: width 0.2s ease;
    }
    .nav-link:hover {
      color: var(--nebula-purple);
    }
    .nav-link:hover::after {
      width: 100%;
    }
    .btn-primary {
      background: linear-gradient(135deg, var(--nebula-purple) 0%, var(--aurora-cyan) 100%);
      color: white;
      font-weight: 600;
      padding: 12px 28px;
      border-radius: var(--radius-button);
      border: none;
      cursor: pointer;
      transition: transform var(--transition-smooth), box-shadow var(--transition-smooth);
      display: inline-block;
      text-align: center;
      box-shadow: 0 8px 18px rgba(108, 92, 231, 0.2);
      font-size: 0.95rem;
      letter-spacing: 0.3px;
    }
    .btn-primary:hover {
      transform: scale(1.03);
      box-shadow: 0 12px 28px rgba(108, 92, 231, 0.3);
    }
    .btn-secondary {
      background: transparent;
      border: 1.5px solid var(--nebula-purple);
      color: var(--nebula-purple);
      font-weight: 600;
      padding: 12px 28px;
      border-radius: var(--radius-button);
      cursor: pointer;
      transition: background 0.2s ease, color 0.2s ease;
      display: inline-block;
      text-align: center;
      font-size: 0.95rem;
    }
    .btn-secondary:hover {
      background: rgba(108, 92, 231, 0.05);
    }
    .btn-ghost {
      background: transparent;
      border: 1.5px solid white;
      color: white;
      font-weight: 600;
      padding: 12px 28px;
      border-radius: var(--radius-button);
      cursor: pointer;
      transition: background 0.2s ease;
    }
    .btn-ghost:hover {
      background: rgba(255,255,255,0.1);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      z-index: 60;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--text-primary);
      transition: 0.3s;
    }
    @media (max-width: 768px) {
      .nav-links {
        position: fixed;
        top: 0;
        right: -100%;
        width: 75%;
        max-width: 320px;
        height: 100vh;
        background: white;
        flex-direction: column;
        padding: 100px 32px 40px;
        gap: 28px;
        box-shadow: -10px 0 30px rgba(0,0,0,0.05);
        transition: right 0.3s ease;
        align-items: flex-start;
      }
      .nav-links.active {
        right: 0;
      }
      .hamburger {
        display: flex;
      }
      .nav-link {
        font-size: 1.2rem;
        font-weight: 500;
      }
      .btn-primary {
        padding: 14px 24px;
        width: 100%;
      }
    }
    /* Hero粒子动画 */
    .hero-particle {
      position: absolute;
      background: white;
      border-radius: 50%;
      opacity: 0.6;
      animation: floatParticle 10s infinite alternate ease-in-out;
      box-shadow: 0 0 12px rgba(108,92,231,0.5);
    }
    @keyframes floatParticle {
      0% { transform: translate(0, 0) scale(1); }
      100% { transform: translate(20px, -30px) scale(1.2); }
    }
    /* 滚动渐显动画 */
    .fade-in-up {
      opacity: 0;
      transform: translateY(28px);
      transition: opacity 0.6s ease, transform 0.6s ease;
    }
    .fade-in-up.visible {
      opacity: 1;
      transform: translateY(0);
    }
    /* 手风琴 */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
    }
    .faq-question {
      cursor: pointer;
      padding: 20px 0;
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
      color: var(--text-primary);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease, padding 0.4s ease;
      color: var(--text-secondary);
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-bottom: 20px;
    }
    .faq-icon {
      transition: transform 0.3s ease;
    }
    .faq-item.active .faq-icon {
      transform: rotate(180deg);
    }
    /* 自定义卡片与布局 */
    .feature-large-card {
      background: linear-gradient(135deg, #1E1B2E 0%, #0B0E14 100%);
      border-radius: var(--radius-card);
      padding: 40px;
      color: white;
      box-shadow: var(--shadow-card);
    }
    .feature-small-card {
      background: white;
      border-radius: var(--radius-card);
      padding: 28px;
      box-shadow: var(--shadow-card);
      transition: box-shadow 0.3s ease, transform 0.2s;
    }
    .feature-small-card:hover {
      box-shadow: var(--shadow-card-hover);
      transform: translateY(-4px);
    }
    .scenario-card {
      background: white;
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: transform 0.3s ease, box-shadow 0.3s;
    }
    .scenario-card:hover {
      transform: translateY(-8px);
      box-shadow: var(--shadow-card-hover);
    }
    .trust-logo {
      filter: grayscale(1);
      opacity: 0.7;
      transition: filter 0.3s, opacity 0.3s;
      max-height: 32px;
    }
    .trust-logo:hover {
      filter: grayscale(0);
      opacity: 1;
    }
    .count-up {
      font-family: 'Inter', sans-serif;
      font-weight: 700;
      background: linear-gradient(135deg, var(--nebula-purple), var(--aurora-cyan));
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }