Page seperators not styling in index

As you can see in the Generate Index window, you can't apply a style to the page separators. But in your screenshot it looks as if the comma is in the same font as the topic name. So what you can do is set that font as the paragraph's basic font and use a character style for the page numbers.

But if the commas are not in the same font as the topic names you can use the following workaround:

1. In the Generate Index window, use a unique character or string for the page separator, e.g. ##

2. Generate the index

3. Use a replacement to apply a character style to ## and replace ## with a comma.

P.