This is a nice way of saying it's nearly unreadable to the point where i wonder if it looks radically different on the developers device.
I don't find it to be "nearly unreadable" myself, but yes it's difficult. I think it depends mostly on the quality of your monitor, and on how it is calibrated.
It's the contrast, or lack thereof. Black text on a gray background is going to be hard to read on any display.
I dismissed it as "they probably developed it for Chrome" and then used the inspector to set background to white. I can't imagine how this is not a bug.
I literally just set `background: white` as the only change and it actually makes it look really good!
Worrying from a group that writes UI for a living.
Someone needs to get over themselves and start thinking about their users.