How to use CSS classes in a custom card?

1

Hello,

I’m creating a custom card using the HA documentation here : https://developers.home-assistant.io/docs/frontend/custom-ui/lovelace-custom-card/

Then I try to apply on div / span custom classes which are defined in a custom CSS file imported via the Locelace Board.

I checked that CSS file is loaded, it is.

Example :
<span class="blink">${stateSensorStr}</span>

CSS :

.blink {
  background: red;
}

Does someone had this issue ?