Hide "All Favorites" AND remove borders

[m40566]

I've been going in circles on this: hiding "All Favorites" in the Media view and removing the borders. This was my latest idea to wrap the sonos card in the stack-in-card and apply styling there, but it didn't work either. What am I doing wrong?

type: custom:stack-in-card
cards:
  - type: custom:sonos-card
    sections:
      - media browser
    entities:
      - media_player.living_room
    excludeItemsInEntitiesList: true
    topFavorites:
      - Apple Music 1
      - Apple Music Hits
      - CH 55 - SiriusXM Chill
      - CH 68 - Spa
    dynamicVolumeSliderThreshold: 100
    hideGroupCurrentTrack: true
    dynamicVolumeSlider: true
    hideBrowseMediaButton: true
    mediaBrowserHideTitleForThumbnailIcons: true
    showVolumeUpAndDownButtons: false
    numberOfFavoritesToShow: 4
    heightPercentage: 25
    card_mod:
      style:
        sonos-media-browser$: |
          sonos-media-browser-header {
            display: none;
          }
card_mod:
  style: |
    ha-card {
      background: rgba(0,0,0,0) !important;
      border: none !important;

[punxaphil]