Custom simple-thermostat target temperature font

Configuration Frontend
1

Recently my thermostat cards using custom simple-thermostat card have changed. The most notable change is the target temperature font size. Efforts to style that font size or for that matter anything else using card_mod have been without success.

type: custom:simple-thermostat
entity: climate.bh_hp
card_mod: null
style: |
  ha-card {
  --st-font-size-sensors: 14px;}
layout:
  step: row
  mode:
    headings: false
sensors:
  - entity: sensor.hp_heat_time_hm
    name: Heat Time
    unit: h:m
  - entity: sensor.bh_hp_heating_rnd
    name: Heat Hrs
  - entity: sensor.hp_cool_time_hm
    name: Cool Time
    unit: h:m
header:
  name: Heat Pump
  icon: mdi:home-thermometer-outline
  faults:
    - entity: binary_sensor.bh_hp_air_filter
      hide_inactive: true
step_size: "1"
setpoints:
  target_temp_low: 76
  target_temp_high: 72
decimals: "0"
control:
  hvac:
    "off": true
  fan: true
  preset:
    none:
      name: Run Sched
    hold: true
    away: true
    temperature:
      name: Manual
2

The first thing I see wrong is you didn’t properly indent style and you have null for card_mod:.

Try this…

type: custom:simple-thermostat
entity: climate.bh_hp
card_mod:
  style: |
    h3.current--value {
      font-size: 35px;
    }
3

If you would like to change the colour both dial and background and font colour, I use this:

card_mod:
  style: |
    ha-card {
      height: 150px; /* Adjust the height as needed */
      width: 150px;  /* Adjust the width as needed */
    }
    .dial {
      user-select: none;
      --thermostat-off-fill: rgba(10,10,100,1);
      --thermostat-path-color: rgba(254, 255, 49, 1);
      --thermostat-text-color: white;
    }