body {
  font-family: sans-serif;
  padding: 20px;
  background: #f4f4f4;
  text-align: center;
}

h1 {
  font-size: 2rem;
  margin-bottom: 10px;
}

.controls {
  margin: 10px auto;
}

.main-container {
  display: flex;
  justify-content: center;
  margin-top: 20px;
}

.canvas-wrapper {
  background: white;
  border: 2px solid #ccc;
  border-radius: 8px;
  padding: 10px;
/*  width: 640px;*/
}

#canvas {
/*  width: 100%;*/
/*  height: 500px;*/
  border: 1px dashed #aaa;
  background: #fff;
  border-radius: 4px;
}