使用column-gap属性设置列之间的间隔。您可以尝试运行以下代码以实现值为50px的column-gap属性：
<!DOCTYPE html>
<html>
<head>
<style>
.demo {
column-count: 4;
column-gap: 50px;
}
</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>