#dropZone {
    border: 2px dashed #ccc;
    padding: 30px;
    text-align: center;
    cursor: pointer;
    color: #999;
    transition: background 0.3s;
  }
  #dropZone:hover {
    background: #f1f1f1;
  }
  canvas {
    margin: 10px;
    border: 1px solid #ccc;
    border-radius: 4px;
  }
  pre {
    background: #f0f0f0;
    padding: 10px;
    border-radius: 5px;
  }