/* Căn giữa canvas trên trang */
body {
  font-family: Arial, sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  margin: 0;
  background-color: #ffffff;
}

/* Khung chứa canvas */
.canvas-container {
  display: flex;
  justify-content: center;
  align-items: center;
}

/* Kiểu dáng viền cho canvas */
canvas {
  border: 1px solid #ccc;
  display: block;
}