/* roulang page: index */
:root {
      --deep-purple: #0b0c10;
      --dark-surface: #0f0f1a;
      --card-bg: rgba(20, 22, 38, 0.75);
      --card-border: rgba(0, 240, 255, 0.15);
      --electric-cyan: #00f0ff;
      --hot-pink: #ff2a6d;
      --text-primary: #f0f3fa;
      --text-secondary: #b0b8d1;
      --radius-lg: 16px;
      --radius-full: 999px;
      --shadow-card: 0 8px 32px rgba(0, 0, 0, 0.45);
      --shadow-glow: 0 0 22px rgba(0, 240, 255, 0.25);
      --font-sans: 'Inter', 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
      --font-mono: 'Space Grotesk', 'Inter', monospace;
    }
    * {
      box-sizing: border-box;
    }
    body {
      margin: 0;
      font-family: var(--font-sans);
      background: var(--deep-purple);
      color: var(--text-primary);
      line-height: 1.5;
      -webkit-font-smoothing: antialiased;
      background-image: radial-gradient(circle at 30% 20%, rgba(45, 226, 230, 0.08) 0%, transparent 35%);
    }
    .container {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 24px;
      padding-right: 24px;
    }
    /* 悬浮胶囊导航 */
    .nav-capsule {
      background: rgba(15, 15, 26, 0.8);
      backdrop-filter: blur(14px);
      -webkit-backdrop-filter: blur(14px);
      border: 1px solid rgba(0, 240, 255, 0.18);
      border-radius: var(--radius-full);
      padding: 8px 28px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      transition: all 0.3s ease;
      box-shadow: 0 10px 28px rgba(0,0,0,0.6);
    }
    .nav-link {
      color: var(--text-secondary);
      text-decoration: none;
      font-weight: 500;
      font-size: 0.95rem;
      transition: color 0.2s, text-shadow 0.2s;
      position: relative;
      padding: 4px 0;
    }
    .nav-link:hover {
      color: var(--electric-cyan);
      text-shadow: 0 0 8px rgba(0,240,255,0.5);
    }
    .nav-link.active {
      color: var(--electric-cyan);
    }
    .nav-link.active::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 50%;
      transform: translateX(-50%);
      width: 6px;
      height: 6px;
      background: var(--electric-cyan);
      border-radius: 50%;
      box-shadow: 0 0 12px var(--electric-cyan);
    }
    /* 按钮系统 */
    .btn-primary {
      background: var(--electric-cyan);
      color: #0b0c10;
      font-weight: 700;
      padding: 14px 32px;
      border-radius: var(--radius-full);
      border: none;
      cursor: pointer;
      transition: 0.3s ease;
      box-shadow: 0 4px 18px rgba(0,240,255,0.35);
      letter-spacing: 0.5px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
    }
    .btn-primary:hover {
      background: #5cf0ff;
      box-shadow: 0 0 28px rgba(0,240,255,0.65);
      transform: translateY(-2px);
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--electric-cyan);
      color: var(--electric-cyan);
      font-weight: 600;
      padding: 14px 32px;
      border-radius: var(--radius-full);
      cursor: pointer;
      transition: 0.3s ease;
      backdrop-filter: blur(4px);
    }
    .btn-outline:hover {
      background: rgba(0,240,255,0.12);
      box-shadow: 0 0 18px rgba(0,240,255,0.3);
      transform: translateY(-2px);
    }
    /* 卡片通用 */
    .glass-card {
      background: var(--card-bg);
      border: 1px solid var(--card-border);
      border-radius: var(--radius-lg);
      backdrop-filter: blur(8px);
      box-shadow: var(--shadow-card);
      transition: all 0.3s ease;
    }
    .service-card:hover {
      transform: translateY(-8px);
      box-shadow: 0 14px 38px rgba(0,0,0,0.7), 0 0 0 1px rgba(0,240,255,0.4);
      border-color: rgba(0,240,255,0.5);
    }
    .metric-digit {
      font-family: var(--font-mono);
      font-weight: 700;
      color: var(--electric-cyan);
    }
    /* 网格背景纹理 */
    .grid-bg {
      background-image: 
        linear-gradient(rgba(0,240,255,0.04) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0,240,255,0.04) 1px, transparent 1px);
      background-size: 40px 40px;
    }
    /* FAQ手风琴 */
    .faq-item {
      border-bottom: 1px solid rgba(255,255,255,0.08);
    }
    .faq-question {
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 20px 0;
      font-weight: 600;
      transition: color 0.2s;
      position: relative;
    }
    .faq-question:hover {
      color: var(--electric-cyan);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.45s ease-in-out, padding 0.3s;
      color: var(--text-secondary);
      padding-left: 16px;
      border-left: 3px solid transparent;
    }
    .faq-item.active .faq-answer {
      max-height: 180px;
      padding-top: 12px;
      padding-bottom: 20px;
      border-left-color: var(--electric-cyan);
    }
    .faq-item.active .faq-question {
      color: var(--electric-cyan);
    }
    @media (max-width: 768px) {
      .nav-capsule {
        padding: 8px 16px;
      }
      .nav-link {
        font-size: 0.8rem;
        margin: 0 4px;
      }
      h1 {
        font-size: 2.6rem !important;
      }
    }
    @media (max-width: 520px) {
      .nav-capsule {
        justify-content: center;
        flex-wrap: wrap;
        gap: 8px;
      }
    }