body {
    margin: 0;
    overflow: hidden;
    background: #000;
    color: white;
    font-family: monospace;
  }
  #toolbar {
    position: absolute;
    top: 10px;
    left: 10px;
    display: flex;
    gap: 10px;
    background: rgba(0,0,0,0.4);
    padding: 8px 12px;
    border-radius: 6px;
  }
  button {
    padding: 6px 12px;
    border: 1px solid #555;
    background: #222;
    color: white;
    cursor: pointer;
    border-radius: 4px;
  }
  .active {
    background: #444;
    border-color: white;
  }
  canvas {
    display: block;
  }