<!DOCTYPE html>
<html>
    <head>
        <meta charset=utf-8>
        <style type="text/css">
            * {
                margin: 0;
                padding: 0;
            }
            img{
                position:absolute;
                left:0px;
                top:0px;
                z-index:-1;
            }
        </style>
    </head>
    <body>
    	<h1>The countdown to Christmas starts here.</h1>
        <img src="https://gimg2.baidu.com/image_search/src=http%3A%2F%2Fuploads.xuexila.com%2Fallimg%2F1912%2F1135-191202143454.jpg&refer=http%3A%2F%2Fuploads.xuexila.com&app=2002&size=f9999,10000&q=a80&n=0&g=0n&fmt=jpeg?sec=1639984107&t=eca951193e736a17eb96278117bcfb1f" width="100">
        <p>由于图像的 z-index 是 -1，因此它在文本的后面出现。</p>
    </body>
</html>