The shorthand property for column rule is column-rule property. You can try to run the following code to implement the column-rule property
Example
<!DOCTYPE html>
<html>
<head>
<style>
.demo {
column-count: 4;
column-gap: 50px;
column-rule: 2px dotted orange;
}
</style>
</head>
<body>
<div class = "demo">
This is demo text. This is demo text. This is demo text.
This is demo text. This is demo text. This is demo text.
This is demo text. This is demo text. This is demo text.
This is demo text. This is demo text. This is demo text.
This is demo text. This is demo text. This is demo text.
This is demo text. This is demo text. This is demo text.
This is demo text. This is demo text. This is demo text.
This is demo text. This is demo text. This is demo text.
This is demo text. This is demo text. This is demo text.
This is demo text.
</div>
</body>
</html>