Dynamic colors in cards

[jamesvdh]

I would like to dynamically change the color within a card based on a sensor state. In a card YAML this could look like this:

...
  fill:
    colors:
      - "{{ states('sensor.pm2_5_aqi_color') }}"

Based on a sensor defined in Templates:

sensor:
  - name: PM2_5 AQI Color
    unique_id: e415238b-cc6d-4aa5-a894-0e83cbd0a7ed
    state: >-
      {% set pm2_5 = states('sensor.voorhaven_haren_belgium_pm2_5') | int %}
      {% set r, g, b = 0, 0, 0 %}
      {% if pm2_5 < 50 %}
        {% set r = 255 %}
        {% set g = (5.1 * pm2_5) | int %}
      {% else %}
        {% set g = 255 %}
        {% set r = (510 - 5.1 * pm2_5) | int %}
      {% endif %}
      {% set hex_color = '{:02x}{:02x}{:02x}'.format(r, g, b) %}
      {{ '#' + hex_color }}

Which already works: