使用 CSS 在所有段落周围制作一个 1 像素厚的黄色边框。
<!DOCTYPE html>
<html>
<head>
<style>
@(1) {@(6): @(3) solid @(6);}
</style>
</head>
<body>
<p>This is a paragraph.</p>
<p>This is a paragraph.</p>
<p>This is a paragraph.</p>
</body>
</html>
<!DOCTYPE html>
<html>
<head>
<style>
p {border: 1px solid yellow;}
</style>
</head>
<body>
<p>This is a paragraph.</p>
<p>This is a paragraph.</p>
<p>This is a paragraph.</p>
</body>
</html>