Adjust height and gaps in comments

Web embedded chat widget.
The space between users chatting is too large for a larger group in the chat. The conversations quickly leave the screen as people comment. I would like to reduce the gaps between the comments to squeeze more comments into the window. They leave way too fast before someone can choose to read or reply to them. Is there a way to adjust the height/spacing? I tried to search this out and could not find anything. Thanks for your help.