Change icon colour with card-mod for cover

Configuration Frontend
1

Hello, I’m new to HA and card-mod. I try to change the colour of a cover icon. The standart is purple and blue, what is not a good diffrence to my background. I wan’t to change it to red and cyn for example. I don’t get what am I doing wrong.

type: horizontal-stack
cards:
  - type: picture-elements
    elements:
      - type: state-icon
        entity: cover.rollo_bad_eg
        tap_action:
          action: perform-action
          perform_action: cover.toggle
          target:
            device_id: ca085240e3cb78901b5370f348a4f5f0
          data: {}
        style:
          left: 4%
          top: 24%
        card_mod:
          style: |
            :host {
             {% if states(config.entity) != '50' %}
             --card-mod-icon-color: cyan;
             color: red;
             {% endif %};
             }
2

Suggest to ask similar questions in the main card-mod thread.
Also, the 1st post of this thread has a link at the bottom which leads to a list of examples.