Element.style on profile hovercard, where is it?

[DZComposer]

I'm designing a custom theme for my site, but I ran into a sticky spot: I wanted to add a border to my hovercards.

Of course, when I do a few pixels of the user profile hovercard's (This is the hovercard in the topic view) contents get truncated, obviously indicating a fixed width. Well, it turns out that the fixed width is defined in an element.style. Where is the code that calls the hovercards? I've looked through all of the phtml files that I guessed could have it, but they're not there.

Could this please be defined as a class in the future so that the hovercard can be changed in custom.css rather than digging for the html line with a style property?