How to colour min/max value?

Please review this thread

and post questions in that thread

An example, but based off your card_mod code it is hard to understand what you trying to achieve.

type: entities
show_header_toggle: true
state_color: true
entities:
  - entity: sensor.living_room_humidity
    card_mod:
     style:
      hui-generic-entity-row:
        $: |
         .text-content:not(.info) {
            color: cyan;
            font-weight: bold;
          }