<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Canvas</title>
  <style>
    canvas {
      width: 256px;
      height: 256px;
    }
  </style>
</head>
<body>
  <canvas width="512" height="512"></canvas>
</body>
</html>