Sensor data font color control

Hi,
How do I control the font color of my sensor data depending on the background color. I can choose the background on my background .png but if I choose black backround the sensor data is black (invisible) on my PC but white on my Android. If I choose white background the sensor data show black (still) on my PC but are light grey (hardly visible) on my Android.

Here is the code:

theme: Backend-selected
    title: Schema
    path: schema
    icon: mdi:clipboard-flow-outline
    type: panel
    badges: []
    cards:
      - type: picture-elements
        elements:
          - entity: binary_sensor.compressor
            style:
              left: 36%
              top: 60%
            type: state-icon
          - entity: binary_sensor.switch_valve_1
            style:
              left: 77%
              top: 36%
            type: state-icon
          - entity: sensor.radiator_return
            style:
              left: 64%
              top: 13%
            type: state-label
          - entity: sensor.heating_setpoint
            style:
              left: 42%
              top: 20%
            type: state-label
          - entity: sensor.heat_carrier_forwrd
            style:
              left: 69%
              top: 66%
            type: state-label
          - entity: sensor.heat_carrier_return
            style:
              left: 69%
              top: 81%
            type: state-label
          - entity: sensor.brine_in_evaporator
            style:
              left: 15%
              top: 57%
            type: state-label
          - entity: sensor.brine_out_condenser
            style:
              left: 15%
              top: 80%
            type: state-label
          - entity: sensor.warm_water_2_mid
            style:
              left: 87%
              top: 57%
            type: state-label
          - entity: sensor.hot_gas_compr
            style:
              left: 47%
              top: 57%
            type: state-label
          - entity: sensor.indoor
            style:
              left: 19%
              top: 39%
            type: state-label
          - entity: sensor.outdoor
            style:
              left: 8%
              top: 20%
            type: state-label
          - entity: sensor.add_heat_status
            style:
              left: 57%
              top: 43%
            type: state-label
        image: https://portal.husdata.se/img/BV_3_HA.png