Custom button card states

I am using https://github.com/custom-cards/button-card#state for a custom button that I would like to simply turn off all lights, I have a group for all the lights and it works ok as a toggle but I am not sure what the syntax is to simply have that as a switch off button only.
Can someone assist please.

This what the toggle one looks like:

     - color: auto
        color_type: card
        entity: group.all_int_ext_lights
        label: Spots
        name: All Lights
        show_label: false
        size: 50%
        state:
          - color: yellow
            value: 'on'
          - color: white
            value: 'off'
        styles:
          card:
            - height: 150px
            - width: 150px
          label:
            - font-size: 14px
          name:
            - font-size: 14px
        type: 'custom:button-card'