html, body {
  margin: 0;
  padding: 0;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  font-family: 'Arial', sans-serif;
  height: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
}

canvas {
  display: block;
  border-radius: 15px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
}