appearance font does not change

appearance font does not change, and is unreadable on firefox, on chrome it seems ok, but still It's hard to read.

User-Agent : Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2490.86 Safari/537.36

I emailed the zm-feedback@zohocorp.com but noreply for 3 days.