This should be good for adding styles for stack-in-card’s ha-card:
type: custom:stack-in-card
...
card_mod:
style: |
ha-card {
...
}
The “.type-custom-stack-in-card” may be used (never tested myself with THIS particular card - but it should be OK) in card-mod themes like
card-mod-card-yaml: |
.: |
ha-card.type-custom-stack-in-card {
...
}
to apply global styles for all stack-in-cards (card-mod themes are discussed here).