--card-mod-icon-color used to work, but now not working

Configuration Frontend
1

This used to work to change icon color, but it no longer does as of latest HA update.

What am I doing wrong?

Thanks.

      - type: entity
        entity: sensor.room_state
        attribute: motion
        name: Motion
        card_mod:
          style: |
            :host {
              --card-mod-icon-color: {{ 'gold' if state_attr('sensor.room_state', 'motion') == 'on' else 'var(--paper-item-icon-color)' }};
            }
        icon: mdi:motion-sensor