How to add Add multiple classes to one HTML element

See the Example.

index.html

Example: HTML

<!DOCTYPE html>
<html>
<head>
<style>
h1.intro {
  color: blue;
  text-align: center;
}

.important {
  background-color: yellow;
}
</style>
</head>
<body>

<h1 class="intro important">Header 1</h1>
<p>A paragraph.</p>

</body>
</html>

Output should be:

Type:	html
Category:	Web Tutorial
Sub Category:	HTML Global Attributes
Uploaded by:	Admin