For example, I have a category that I would like to set differently in respect of colors, etc (different on the main page differently on the subpages)
You can! There are HTML classes you can target with CSS that should give you all the customizability you should need. You can track them down using your browser’s web inspector.
For example, a category class is added to the
<body> tag on a category and its topics.
It’s a little trickier to target user groups. We include a user group class with a user’s post if they have the group set as their primary group. A primary group can be established through user group setting, by a staff member, or by the user if the
user selected primary groups site setting is enabled.