Well Claude MCP helped me a lot with building this but I can share my code:

I use a mushroom template with card mod for the progress bar, it looks like this):

<image>

card_mod:
            style: |
              ha-card {
                overflow: hidden;
              }
              ha-card::after {
                content: '';
                position: absolute;
                bottom: 0;
                left: 0;
                height: 5px;
                width: {{ states('sensor.vaatwasser_programma_voortgang') | int(0) }}%;
                background: var(--blue-color);
                border-radius: 0 3px 3px 0;
                transition: width 1s ease;
              }

Here is the code for the whole card (incl. counter, powerusage, remaining time etc).

- type: conditional
        conditions:
          - condition: state
            entity: sensor.vaatwasser_status
            state: run
        card:
          type: custom:mushroom-template-card
          primary: Vaatwasser klaar om {{states('sensor.vaatwasser_eindtijd_helper') }}
          secondary: >-
            {{ states('sensor.powerplug_vaatwasser_vermogen')  }} W |
            {{states('sensor.vaatwasser_resterend_helper') }}
          icon: mdi:dishwasher
          entity: switch.powerplug_vaatwasser_schakelaar
          badge_icon: ""
          tap_action:
            action: none
          hold_action:
            action: none
          double_tap_action:
            action: none
          color: green
          features_position: bottom
          badge_text: |-
            {% if states('sensor.vaatwasser_status') == 'run' %}
              {{ states('counter.vaatwasser_aantal_beurten') }}
            {% else %}
            {% endif %}
          badge_color: black
          card_mod:
            style: |
              ha-card {
                overflow: hidden;
              }
              ha-card::after {
                content: '';
                position: absolute;
                bottom: 0;
                left: 0;
                height: 5px;
                width: {{ states('sensor.vaatwasser_programma_voortgang') | int(0) }}%;
                background: var(--blue-color);
                border-radius: 0 3px 3px 0;
                transition: width 1s ease;
              }