Try like below in your field A background color properties,
your field A
refer sample app.
QlikSense_253330.qvf 176.0 K
Hi, I am afraid we cannot achieve this directly. As a workaround, i think we can do the following.
1. first go to color settings in KPI Object. In QS 3.2, it is there under Appearance.
2. Enable the conditional color option.
3. Enter the expression in this format.
4. Arrange the limit scroll bar at the center if you want to use only two colors. Or add add more limits.
5. Choose the color from the list by click the on the bar.
P.S: You can select color from the list only.