How to visualize a central heating outage alarm?

On my central heating there is a relay output that closes a contact if everything is fine, and opens it if a fault is detected or if there is a powerloss. I’ve connected this by a wifi-node into my HA as a binary sensor.

What do you suggest to use here as the card? Currently i’ve just using the default card “entities”, but there may be better ones, showing a visual alarm and not just a circle-hook symbol?

I also wonder if it is possible to send me a warning message onto my smartphone (SMS, or HA-APP) if such things happens?