A CSS class , an attribute used to define a group of HTML elements in order to apply unique styling and formatting to those elements with CSS.
Example :
<!DOCTYPE html>
<html lang="en">
<head>
<title>Class & Element</title>
<style>
h1.intro {
background-color: yellow;
color: red;
font-weight: bold;
}
</style>
</head>
<body>
<h1 class="intro">Class & Element Selector</h1>
<p class="intro">The style is not applied here.</p>
<h1 class="intro">When used with h1 element style sheet is applied here.</h1>
</body>
</html>
Show Output :
