/* roulang page: index */
:root {
      --primary: #0D9488;
      --secondary: #0284C7;
      --accent: #F97316;
      --bg-gray: #F8FAFC;
      --text-main: #1E293B;
      --text-muted: #64748B;
      --border: #E2E8F0;
      --shadow-soft: 0 10px 30px -5px rgba(15, 23, 42, 0.05);
      --shadow-hover: 0 20px 35px -5px rgba(15, 23, 42, 0.12);
    }
    html {
      scroll-behavior: smooth;
      font-family: system-ui, -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    }
    body {
      color: var(--text-main);
      background-color: var(--bg-gray);
      line-height: 1.7;
    }
    .custom-shadow {
      box-shadow: var(--shadow-soft);
      transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    }
    .custom-shadow:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
    }
    .hero-bg-overlay {
      background: linear-gradient(180deg, rgba(15, 23, 42, 0.75) 0%, rgba(15, 23, 42, 0.88) 100%);
    }
    .glass-nav {
      background: rgba(255, 255, 255, 0.95);
      backdrop-filter: blur(12px);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease-out, opacity 0.25s ease;
      opacity: 0;
    }
    .faq-item.active .faq-answer {
      max-height: 240px;
      opacity: 1;
    }
    .faq-item.active .faq-arrow {
      transform: rotate(180deg);
    }
    .tap-target {
      min-width: 44px;
      min-height: 44px;
    }