console
<html>
<head>
<style>
.gray {
-webkit-filter: grayscale(100%);
-moz-filter: grayscale(100%);
-ms-filter: grayscale(100%);
-o-filter: grayscale(100%);
filter: grayscale(100%);
filter: gray;
}
</style>
<title>黑白主题网页</title>
</head>
<body>
<div class='gray'>
<fieldset>
<legend>黑白效果</legend>
<p style="color:red;" >红色文字</p>
<p style="color:green;background-color:yellow;">绿色文字黄色背景</p>
<p>彩色照片</p>
<img src="https://p.fkcaijing.com/UC/20221201/16698364263.png" alt="彩色照片" width=200>
</fieldset>
</div>
<div class=''>
<fieldset>
<legend>彩色效果</legend>
<p style="color:red;" >红色文字</p>
<p style="color:green;background-color:yellow;">绿色文字黄色背景</p>
<p>彩色照片</p>
<img src="https://p.fkcaijing.com/UC/20221201/16698364263.png" alt="彩色照片" width=200>
</fieldset>
</div>
</body>
</html>