Because the js takes input parsed to it via home assistant, it’s just blank when I paste the js code into JSFiddle.
Something has changed in the last few days in the way Brave is using css I think. It has been working perfectly for a fair while until yesterday.
Interesting that Chrome, Edge etc have all started presenting the same error now as well so looks like whatever has been changed is being implemented by all browsers, just Brave was the first. We came up with a fix anyway in the div code in the card.
Thanks for your willingness to help us fix this though. I bet if I asked chrome support a similar question I would have even gotten a response.