body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  margin: 0;
  padding: 20px;
  background-color: #f4f4f4;
  color: #333;
}
.outer {
  background-color: #fff;
  margin: 20px auto;
  max-width: 1000px;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
  border-radius: 8px;
  overflow: hidden;
}
.container {
  padding: 20px;
}

#canvas {
  margin: 0 auto;
  display: block;
}