[Mikevet1984]

Take a look at this short tutorial.

Enter Admin CP --> Usergroups --> Usergroup Manager

<Edit usergroup> for every usergroup you would like to edit. Click on the GO button.

When the permission page loads go to <Username HTML Markup > option. You will find there two empty boxes.

In the first one write:

<span style="font: 12px Tahoma; color: #FF0000; font-weight: bold;">

Change the font settings as you wish for the usergroup. #FF0000 is the html color, this is what you are looking for. For more color htmls take a look here and replace the #FF0000 with whatever you like.

In the second one write:

</span>

Take a look at the attached screenshot.

Hope I was useful and helped.

Regards!