lovecoding
/
VIP20


			
				
					
						
						
							12345678910111213141516171819202122232425262728
							<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    *{
      margin: 0;
      padding: 0;
    }
    #div1{
      width: 1rem;
      height: 300px;
      background: red;
    }
    /* 
      rem 相对于根元素的字体大小
      rem.js  获取屏幕的宽度  然后根据屏幕宽度去设置html字体大小
    */
  </style>
</head>
<body>
  <div id="div1"></div>
  <script src="rem.js"></script>
</body>
</html>