Global alert bar: API down

[uiuxxx]

The API has gone down several times recently, which has caused confusion to users. Let's add a global alert bar explaining the situation.

Text: fontWeight="bold" color="font.dark" bg="orange.400"

The Balancer API is currently down, causing most site features to be unavailable. The issue is being worked on to restore full service.

There is no different light mode / dark mode. Its the same colors for both.

[agorer]