@vatsal Yes I'm sure "folder-name" : "public/folder-name" means you can use /plugins/your-theme-name/folder-name/whatever
The first parameter correspond to the name that will be used after theme-name/folder, while second parameter means this alias points to path.
@SimonQ I am not using the last version of this plugin (I made a fork when the regex issue arised) so I could not reproduce your problem. So I just tried on a testing version of the forum I am in charge and I observe the same behaviour. So it is not just you. I suppose it is a question of tweaking the css though. I will try to have look but I am VERY far to be an expert.