Border line of polygons with rampcolors using QGIS

Question

I am trying to change the border line of all categories of a vector layer in QGIS 3.0, but I can't find how to do it.

My question is not how to fill each category with different colors. When I try to select simple fill, all border lines get the same color and I would have to change each category separately. I have the same problem as described in the comment of the accepted answer of this question: Changing categorized style color simultaneously in QGIS?

Any tips?

Answer 1

Before categorizing your layer, switch the symbol from "simple fill" to "border: simple line". This will leave your without the ability to fill the polygons, but QGIS differentiates the categories via the border instead of the fill.