In a discussion titled “Different themes per category?” within the Support category, user downey asks if it’s possible to use multiple themes for different categories on the same Discourse installation. Falco clarifies that while full themes can’t be applied per category, different CSS styles can be targeted using the category-specific class on the body element. Falco provides a SASS example showing how to scope styles to a category like body.category-support. downey acknowledges familiarity with the technique but hoped for a faster method. Later, PackElend expands the inquiry, asking if theme components (like Kanban) can be activated per category and if navigation elements (Favorites, Assign, Agenda, Tickets) can be conditionally displayed. PackElend requests a more detailed tutorial, to which downey replies that the topic is outdated and suggests opening a new support thread. PackElend reiterates the request for clarification, citing the original discussion as the most relevant source for the technique. The core takeaway is that category-specific styling is possible via CSS/SASS with body class targeting, though full theme switching per category is not supported.
Forgive the newbie question – I am not yet well versed in the theme system.
Is there any way to possibly use multiple themes for the same installation? In other words, for example, have one theme in use for a specific category and another theme be default site-wide/elsewhere?
Not themes, but different styles you can. There is a class with the category name on the body.
Ah, OK. I’ve done that previously, or something close to it, so am familiar with the idea. Just wondered if there might be a faster way to adopt different styling between categories. Thanks! 
With SASS scoped selectors it’s pretty easy:
// put main theme here
body.category-support {
// paste another theme here
}
means that I can use different theme components too
e.g. standard for everyone, kanban if you switch to “task”
can you share a bit more detailed tutorial on how to do that, I would like to do the same but cannot follow you
@Falco and @downey would you mind to grant me some insight?
Moreover, can I add an entry in the hamburger menu what switches to predefined filter and activates the Kanban Board (or any other of the those lsited below)
In addition, is shall make visible
in the navigation bar.
That’s most likely because this support question is 2.5 years old. 
If you are having trouble with installing or switching themes, probably best to open a new Support topic with your specific challenges.
done but
was discussed here so you might be the one who is be able to explained it in bit more detail