See screenshot:
The ‘yes’ button is white-on-lightgrey-on-white and thus unreadable.
I’m using the latest Chrome on the latest OSX.
I’ve noticed this to but though it was on purpose, to discourage people from abandoning their post and contribute what ever it was they were writing (maybe I’m being a bit too optimistic…)
Making things unreadable is never a good way to discourage an action 
I hope this is an issue and not by design 
Well, it’s really an issue with Discourse - not Ionic. I’ve been kind of ignoring it for a while. Bigger fish to fry?