Very interesting solutions and a nice look.
I especially like the highlighted lighting “card” in the middle.
Two tips.
Since Home Assistant 0.88, there’s a theme variable called ha-card-border-radius which can replace border-radius in card-modder, and in 0.89 there will be a ha-card-box-shadow, so you won’t need card moder at all for most of your cards.
An alternative way of making the “OFFICE” card is to put cards in an entities card. You do this by pretending that the card is a custom entity row with the name hui-<card name>-card (or just use the normal name if it’s a custom card), so you can do e.g.
type: entities
entities:
- type: custom:hui-horizontal-stack-card
cards:
- type: custom:button-card
...etc...
- type: custom:hui-entities-card
entities:
- input_select.office_mode