Trouble with Background image for button card

Newbie to card mod and css styles here. I’ve been playing around with some room cards using a combination of button card/mushroom. Following along with the ideas from https://www.youtube.com/watch?v=RSQwxuAm

I am having a lot of trouble adding in a background image to my card. Trialing first with the first card in the vertical stack below (Master).

Haven’t been able to get it to work under card mod or styles:. Hoping just a newbie mistake but I would appreciate if anyone has any suggestions.

type: vertical-stack
cards:
  - square: false
    type: grid
    cards:
      - type: custom:button-card
        name: Master
        icon: mdi:bed-king-outline
        entity: none
        card_mod:
          style: |
            ha-card > div {
              padding: 0px 0px 0px!important;
            }
            ha-card {          
              padding: 10px 10px!important;
              border: none;
              border-radius: 10px;
              background-image: url("/local/background/MasterBW.jpg")            
              box-shadow: 0px 0px 0px 0px rgba(0,0,0,0.0);   
            }
        custom_fields:
          btn:
            card:
              type: custom:mushroom-chips-card
              chips:
                - type: template
                  tap_action:
                    action: toggle
                  icon: mdi:lightbulb-outline
                  entity: light.philips_bulb_1
                  card_mod:
                    style: |
                      ha-card {
                        --chip-background: {{ 'rgba(255,255,255,0.7)' if is_state('light.philips_bulb_1', 'on') else 'rgba(0,0,0,0.1)' }};
                        border: none;
                        padding: 0px!important;
                        border-radius: 10px!important;
                      }
                - type: template
                  tap_action:
                    action: toggle
                  icon: mdi:led-strip-variant
                  entity: light.philips_strip_1
                  card_mod:
                    style: |
                      ha-card {
                        --chip-background: {{ 'rgba(255,255,255,0.7)' if is_state('light.philips_strip_1', 'on') else 'rgba(0,0,0,0.1)' }};
                        border: none;
                        padding: 0px!important;
                        border-radius: 10px!important;
                      }   
                - type: template
                  tap_action:
                    action: toggle
                  icon: mdi:television
                  entity: media_player.bedroom_tv
                  card_mod:
                    style: |
                      ha-card {
                        --chip-background: {{ 'rgba(255,255,255,0.7)' if is_state('media_player.bedroom_tv', 'on') else 'rgba(0,0,0,0.1)' }};
                        border: none;                       
                        padding: 0px!important;
                        border-radius: 10px!important;
                      } 
        styles:
          grid:
            - grid-template-areas: '"n btn" "s btn" "i btn"'
            - grid-template-columns: 1fr min-content
            - grid-template-rows: min-content min-content 1fr
          card:
            - padding: 10px 10px 10px 10px
            - height: 132px
          custom_fields:
            btn:
              - justify-content: end
              - align-self: start
          name:
            - justify-self: start
            - align-self: start
            - font-size: 18px
            - font-weight: 500
            - color: light-grey
          state:
            - min-height: 80px
            - justify-self: start
            - align-self: start
            - font-size: 14px
            - opacity: '1'
          img_cell:
            - position: absolute
            - width: 60px
            - height: 60px
            - left: 0
            - bottom: 0
            - margin: 0 0 10px 10px
            - background: rgba(0,0,0,0.1)
            - border-radius: 10px
          icon:
            - width: 50px
            - color: light-grey
            - opacity: '1'
        show_state: true
      - type: custom:button-card
        name: Living
        icon: mdi:sofa-outline
        entity: none
        card_mod:
          style: |
            ha-card > div {
              padding: 0px 0px 0px!important;
            }
            ha-card {
              padding: 10px 10px!important;
              border: none;
              border-radius: 10px;
              background-color: rgba(0,0,0,0.1);
              box-shadow: 0px 0px 0px 0px rgba(0,0,0,0.0);
            }
        custom_fields:
          btn:
            card:
              type: custom:mushroom-chips-card
              chips:
                - type: template
                  tap_action:
                    action: toggle
                  icon: mdi:bullhorn-outline
                  entity: switch.neo_siren_1_alarm
                  card_mod:
                    style: |
                      ha-card {
                        --chip-background: {{ 'rgba(255,255,255,0.7)' if is_state('switch.neo_siren_1_alarm', 'on') else 'rgba(0,0,0,0.1)' }};
                        border: none;
                        padding: 0px!important;
                        border-radius: 10px!important;
                      }
                - type: template
                  tap_action:
                    action: toggle
                  icon: mdi:led-strip-variant
                  entity: light.philips_strip_2
                  card_mod:
                    style: |
                      ha-card {
                        --chip-background: {{ 'rgba(255,255,255,0.7)' if is_state('light.philips_strip_2', 'on') else 'rgba(0,0,0,0.1)' }};
                        border: none;
                        padding: 0px!important;
                        border-radius: 10px!important;
                      }   
        styles:
          grid:
            - grid-template-areas: '"n btn" "s btn" "i btn"'
            - grid-template-columns: 1fr min-content
            - grid-template-rows: min-content min-content 1fr
          card:
            - padding: 10px 10px 10px 10px
            - height: 132px
          custom_fields:
            btn:
              - justify-content: end
              - align-self: start
          name:
            - justify-self: start
            - align-self: start
            - font-size: 18px
            - font-weight: 500
            - color: light-grey
          state:
            - min-height: 80px
            - justify-self: start
            - align-self: start
            - font-size: 14px
            - opacity: '0.7'
          img_cell:
            - justify-content: start
            - position: absolute
            - width: 60px
            - height: 60px
            - left: 0
            - bottom: 0
            - margin: 0 0 10px 10px
            - background: rgba(0,0,0,0.1)
            - border-radius: 10px
          icon:
            - width: 40px
            - color: light-grey
            - opacity: '1'
            - padding: 10px
        show_state: true
    columns: 2