body {
  margin: 0;
  font-family: sans-serif;
  background: #f4f4f4;
}

#toolbar {
  position: fixed;
  top: 0;
  left: 0;
  background: white;
  padding: 10px;
  width: 100%;
  z-index: 10;
  display: flex;
  gap: 10px;
  border-bottom: 1px solid #ccc;
}

#canvasContainer {
  margin-top: 60px;
}

canvas {
  border: 1px solid #ddd;
  display: block;
  margin: 20px auto;
  background: white;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
  cursor: crosshair;
}