要选择id =” tutorials”的所有元素，可以尝试运行以下代码。
使用#id CSS选择器可实现此目的，
<!DOCTYPE html>
<html>
<head>
<style>
#tutorials {
border: 3px solid red;
}
</style>
</head>
<body>
<h1>Nhooo</h1>
<h2>Learning</h2>
<p id = "tutorials">Tutorials on web dev, programming, database, networking, etc.</p>
<p>Every tutorials has lessons with illustrations and figures.</p>
</body>
</html>