/* roulang page: index */
:root {
      --primary: #2563eb;
      --primary-hover: #1d4ed8;
      --secondary: #06b6d4;
      --bg-light: #f8fafc;
      --bg-white: #ffffff;
      --text-main: #0f172a;
      --text-body: #334155;
      --text-muted: #64748b;
      --border-color: #e2e8f0;
      --radius-sm: 8px;
      --radius-md: 12px;
      --radius-lg: 16px;
      --shadow-soft: 0 4px 20px -2px rgba(15, 23, 42, 0.05);
      --shadow-hover: 0 12px 28px -4px rgba(37, 99, 235, 0.12);
    }

    html {
      scroll-behavior: smooth;
      font-family: system-ui, -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    }

    body {
      background-color: var(--bg-light);
      color: var(--text-body);
      line-height: 1.75;
      margin: 0;
      padding: 0;
      overflow-x: hidden;
    }

    .custom-shadow {
      box-shadow: var(--shadow-soft);
      transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    }
    .custom-shadow:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-3px);
    }

    .hero-mask {
      background: linear-gradient(135deg, rgba(11, 15, 25, 0.94) 0%, rgba(17, 24, 39, 0.88) 100%);
    }

    .glass-card {
      background: rgba(255, 255, 255, 0.04);
      backdrop-filter: blur(12px);
      border: 1px solid rgba(255, 255, 255, 0.1);
    }

    .faq-content {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease-out;
    }
    .faq-active .faq-content {
      max-height: 280px;
    }
    .faq-active .faq-icon {
      transform: rotate(180deg);
    }

    .sticky-bottom-bar {
      box-shadow: 0 -4px 25px rgba(0, 0, 0, 0.1);
    }