body {
    font-family: Arial, sans-serif;
    line-height: 1.6;
    background-color: #f0f0f0;
    margin: 0;
    padding: 0;
  }
  
  .container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
    background-color: #fff;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
  }
  
  h1 {
    text-align: center;
    margin-bottom: 20px;
  }
  
  .input-group {
    display: flex;
    flex-wrap: wrap;
    margin-bottom: 10px;
  }
  
  .input-group label,
  .input-group select,
  .input-group input {
    margin: 5px;
    padding: 5px;
  }
  
  .calculate-btn {
    display: block;
    width: 100%;
    padding: 10px;
    background-color: #007bff;
    color: #fff;
    border: none;
    cursor: pointer;
  }
  
  .results {
    margin-top: 20px;
  }
  
  .result-details {
    background-color: #f9f9f9;
    padding: 10px;
    margin-top: 10px;
    border-radius: 5px;
  }
  
  .result-details h2 {
    margin-top: 0;
  }