For the past couple of days, I've been trying to create a custom design for the modalWrapper on a wiki that I administrate. But I don't know precisely how to make the modalWrapper look like this.
I think that "border-image" may be one of the classes. But I haven't had any luck trying to find anything that is remotely similar to what I'm trying to achieve. Even when I try and follow some examples presented here, I haven't been able to yield very good results.