Use the CSS :empty selector to style every <p> element that has no children with CSS. You can try to run the following code to implement the :empty selector −
Example
<!DOCTYPE html>
<html>
<head>
<style>
p.demo {
width: 300px;
height: 20px;
background: gray;
}
p:empty {
width: 150px;
height: 20px;
background: orange;
}
</style>
</head>
<body>
<p class = "demo">This is demo text. Below is empty text.</p>
<p></p>
</body>
</html>