body {
  font-family: sans-serif;
  margin: 0;
  background-color: #f0f0f0;
}

header {
  background-color: #333;
  color: white;
  padding: 1rem;
  text-align: center;
}

.back-link {
  position: absolute;
  top: 1rem;
  left: 1rem;
  color: white;
  text-decoration: none;
}

main {
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 2rem;
}

#canvas-container {
  border: 1px solid #ccc;
}