Can I put a border around a stack or individual card?

Can I put a border around a stack or individual card?
I suspect that it may be in “style:”, but I can’t find style: explained in the docs.

Yes its possible. But you need to install card mod custom card from HACS.

And after that you can add borders like this. Just use the style part.

type: gauge
style: |
  ha-card {
    background-color: #30254f; border: solid 3px white; box-shadow: none;
  } 
entity: sensor.temperature_sensor_2
min: 0
max: 40
name: Ground Floor
severity:
  green: 23
  yellow: 30
  red: 35

FireShot Capture 402 - Overview - Home Assistant - 192.168.33.250

Thanks. I’ll give it a try.
New question- Is there a way to switch from YAML mode to use the Dashboard Editor?

Since we are using a non native card of HA such as Card Mod card, the configuration can only be done with YAML. But this is easy. You can first make the card with the dashboard editor and then switch to YAML and copy just the line with style property. That’s all…you dont need to build the entire card in YAML.

I’m not sure if vertical and horizontal stacks have borders. To get around this you can put your cards in an entities card instead of a vertical stack.

This requires the use of another custom card:

Is there a reason Style is restricted? It seems like if it were available everywhere it would be one of the best features of HA.