Custom-ui.... please help

HI, newbie here. I am setting up my home assistant setup. Goes well, but struggling with some coloring.

I have installed HACS and custom-ui. However I can not get the coloring to work.

What I would like, I have a washing machine icon which I would like to change on color based on amount of energy taken (i.e. either it is not in use or is in use). Green for not in use and red for in use.
However the icon remains white…

Can someone help me what I am doing wrong? thank you!

in configurations.yaml
homeassistant:
customize: !include customize.yaml

In customize.yaml:

sensor.shelly_shplg_s_6a58e9_current_consumption:
icon: mdi:dishwasher
templates:
icon_color: >
if (state <10) return ‘green’;
return ‘red’;