🔹 Card-mod - Add css styles to any lovelace card

I am trying to figure out how to adjust the size of the light adjustment bars in the light card.

I think I’m wasting space, so I would like to have the bar to extend to the left, like I mocked in the screenshot.

(How) can I achieve that with card-mod? And, are there any good tutorials on how to get started with card-mod as a non-developer?

I figured it seems to be the div.container, but I don’t know how to write the card-mod code for that from scratch.

My card code:

square: false
columns: 1
type: grid
cards:
  - type: custom:mushroom-light-card
    entity: light.group_wz_stehlampe
    icon: mdi:sofa
    secondary_info: state
    show_brightness_control: true
    show_color_control: true
    name: Sofa
    icon_type: entity-picture
    tap_action:
      action: toggle
    collapsible_controls: false
    primary_info: name
    show_color_temp_control: true
    use_light_color: true
    layout: horizontal
  - type: custom:mushroom-light-card
    entity: light.sessel
    icon: mdi:sofa-single
    show_brightness_control: true
    use_light_color: false
    secondary_info: state
    show_color_control: true
    show_color_temp_control: false
    fill_container: true
    primary_info: name
    tap_action:
      action: toggle
    hold_action:
      action: more-info
    double_tap_action:
      action: none
    icon_type: entity-picture
    name: Sessel
    collapsible_controls: false
    layout: horizontal
  - type: custom:mushroom-light-card
    entity: light.esstisch
    icon: mdi:ceiling-light
    secondary_info: state
    show_brightness_control: true
    show_color_control: true
    name: Esstisch
    icon_type: entity-picture
    collapsible_controls: false
    tap_action:
      action: toggle
    primary_info: name
    use_light_color: true
    show_color_temp_control: true
    layout: horizontal
  - type: custom:mushroom-light-card
    entity: light.wohnzimmer_kommode
    icon: mdi:buffet
    name: Kommode
    show_brightness_control: true
    primary_info: name
    secondary_info: state
    show_color_temp_control: true
    use_light_color: true
    show_color_control: true
    layout: horizontal
  - type: custom:mushroom-light-card
    entity: light.group_tv_board
    icon: mdi:television
    name: TV-Board
    use_light_color: false
    show_brightness_control: true
    show_color_control: true
    show_color_temp_control: false
    layout: horizontal
  - type: custom:mushroom-entity-card
    entity: switch.steckdose_tv_x_box
    name: TV & X-Box
    icon: mdi:power
    icon_color: green
    secondary_info: state
    icon_type: entity-picture
    tap_action:
      action: toggle
    primary_info: name
    fill_container: true
    layout: horizontal

Thanks for any help!