body {
      font-family: 'Segoe UI', sans-serif;
      background: #f4f6f8;
      margin: 0;
      padding: 2rem;
    }
    h1 {
      text-align: center;
      color: #333;
    }
    .tier-container {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
      gap: 1.5rem;
      margin-top: 2rem;
    }
    .tier-card {
      background: white;
      border-radius: 12px;
      box-shadow: 0 4px 8px rgba(0,0,0,0.1);
      padding: 1.5rem;
      border-left: 10px solid;
    }
    .demo { border-color: #999; }
    .tier1 { border-color: #0078D4; }
    .tier2 { border-color: #28A745; }
    .tier3 { border-color: #FFC107; }
    .tier4 { border-color: #6F42C1; }

    .tier-header {
      font-size: 1.2rem;
      font-weight: bold;
      margin-bottom: 0.5rem;
    }
    .price {
      font-size: 1rem;
      color: #555;
      margin-bottom: 1rem;
    }
    ul {
      padding-left: 1.2rem;
      margin: 0;
    }
    li {
      margin-bottom: 0.5rem;
      line-height: 1.4;
    }