/* roulang page: index */
:root {
      --brand-primary: #1D4ED8;
      --brand-accent: #0EA5E9;
      --bg-base: #F8FAFC;
      --surface: #FFFFFF;
      --text-main: #0F172A;
      --text-body: #334155;
      --text-muted: #64748B;
      --border-line: #E2E8F0;
      --shadow-sm: 0 1px 3px rgba(0,0,0,0.05), 0 10px 15px -5px rgba(0,0,0,0.04);
      --shadow-hover: 0 20px 25px -5px rgba(29, 78, 216, 0.08), 0 8px 10px -6px rgba(0,0,0,0.04);
    }
    html {
      scroll-behavior: smooth;
    }
    body {
      background-color: var(--bg-base);
      color: var(--text-body);
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
      line-height: 1.65;
    }
    .custom-card {
      background: var(--surface);
      border: 1px solid var(--border-line);
      border-radius: 1rem;
      box-shadow: var(--shadow-sm);
      transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    }
    .custom-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
      border-color: #CBD5E1;
    }
    .nav-blur {
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      background-color: rgba(255, 255, 255, 0.92);
    }
    .hero-mask {
      background: linear-gradient(135deg, rgba(15, 23, 42, 0.88) 0%, rgba(30, 58, 138, 0.78) 100%);
    }
    .coupon-edge {
      background-image: radial-gradient(circle at left, transparent 8px, #ffffff 8.5px), radial-gradient(circle at right, transparent 8px, #ffffff 8.5px);
      background-size: 100% 100%;
    }
    details summary::-webkit-details-marker {
      display: none;
    }