通过 css 渲染一个如图所示的晶格状画布背景

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    /* 一个晶格状的画布背景 */
    html,
    body{
      height: 100%;
      margin: 0;
      padding: 0;
    }
    .container {
      height: 100%;
      /* 主要属性 */
      background-color: #fff;
      background-image: linear-gradient(45deg, rgb(247, 247, 247) 25%, transparent 25%),
        linear-gradient(-45deg, rgb(247, 247, 247) 25%, transparent 25%),
        linear-gradient(45deg, transparent 75%, rgb(247, 247, 247) 75%),
        linear-gradient(-45deg, transparent 75%, rgb(247, 247, 247) 75%);
      background-size: 20px 20px;
      background-position: 0 0, 0 10px, 10px -10px, -10px 0;
    }
    .rect{
      position: absolute;
      top: 200px;
      left: 200px;
      width: 120px;
      height: 120px;
      background: pink;
    }
  </style>
</head>
<body>
  <div class="container">
    <div class="rect"></div>
  </div>
</body>
</html>