Bolding Administrator Usernames
 

When I do that it only bolds the Super Administrator username, and not the additional ones. How do I fix that?

What do you mean by "not the additional ones?" What else is it that you want bolded? If you put in <span style="font-weight:bold;"> amd </span> in the Username HTML Markup for Administrators, then it should bold all the Primary users of that group (NOT secondary users).

if you go to the edit user screen in the adminCP, and check the Display usergroup prefreneces, you should be able to select the bolded admin if you have them setup as secondary users

I want the primary, and secondary users in the Administrator group to be bolded.

You can't force styles on a secondary group. You need the user to change their Display Group.