Labels no more use contrasting foreground

Yesterday the labels in my repository were being shown using black or white text color - depending on their background color. Today the labels are shown with black text color - which makes the text on the label completely unreadable when the background color is also black.
This is a bug.

So when I check my labels, this is what I’m seeing:

Could you try logging into GitHub using an Incognito or Private Browsing window? Just to check and see if maybe there’s a browser extension causing mischief.

If that doesn’t make a difference, can you let us know what browser you are using? For reference, we do have a list here of our supported browsers.

Incognito mode does not help. I am using Chrome Version 77.0.3865.120 which apparently does not support CSS min/max functions. However, when I try to edit the label color - the button for color change still has the proper contrast text because it uses an explicit “text-white” CSS class (when appropriate).
I am pretty sure you will answer “we only support the latest browser version”. But I have a reason to still use Chrome v77.