body {
    font-family: Arial, sans-serif;
    text-align: center;
    margin: 20px;
    background-color: #f5f5f5;
  }
  
  h1 {
    margin-bottom: 10px;
  }
  
  .menu {
    margin-bottom: 20px;
  }
  
  label {
    font-size: 16px;
  }
  
  select {
    font-size: 16px;
    padding: 5px;
    margin-left: 10px;
  }
  
  .simulation {
    display: inline-block;
    width: 90%;
    max-width: 500px;
    background: white;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 0 10px rgba(0,0,0,0.2);
    margin: 10px auto;
  }
  
  .hidden {
    display: none;
  }
  
  .button-group {
    margin-top: 10px;
  }
  
  button {
    padding: 10px;
    margin: 5px;
    font-size: 16px;
    cursor: pointer;
  }
  
  .mode-select {
    margin-top: 10px;
    font-size: 14px;
  }
  
  .log {
    margin: 10px;
    padding: 10px;
    background: #eee;
    border: 1px solid #999;
    text-align: left;
    font-size: 14px;
  }
  
  canvas {
    margin: 10px auto;
    background: #eee;
    display: block;
  }
  
  .description {
    margin-top: 15px;
    padding: 10px;
    background-color: #eef;
    border: 1px solid #99c;
    border-radius: 5px;
    text-align: left;
    font-size: 14px;
  }