Nick or name customize, colorful and icon, how to do it?

[ClawdiaWolf (Claudia)]

@cocococosti

I don’t think the username can be customized user by user, unless an admin does it manually with CSS. Or with a custom plugin that introduces that feature.

Something like this should work unless a user’s profile is private:

span.username a[data-user-card="cocococosti"]{
border: solid green 3px;
}

This is what that code looks like here on Meta with your username @cocococosti

EDIT: Misread your post, but still it’s a simple enough example for those who don’t know how to do it.