Maybe on mobile just compress down to the color block for the category and suppress the actual category text.
Or something like this:
It only requires a little more work.
I do not think side by side is a good idea on mobile at all. So go with underneath.
Also on mobile only display 5 topics per section (you can just hide using CSS probably)
I’ll see what I can do.
Until now I’ve tested the code with media queries to do somenthing like this.
From 320px to 799px:
Does it sound reasonable for you?
That’s done on mobile device from 320px to 799px. The topics displayed are 5 now, from 800px they are back to 10.
I still have to solve a small bug with the bullet-style categories before send a pull request.