Mozilla fonts problem

Hello there!

I’m facing some font problems on our website on Mozilla Firefox browser.
If you will open the page you’ll see that font on the Chrome http://prntscr.com/w5gurh will look different with the font on the Firefox http://prntscr.com/w5gv5t(firefox looks like italic or smth).
The font there is the default from the website and is Rubik font from google.
I also tried to set the font with developer tools here http://prntscr.com/w5gwjm. If I’ll point some other font there, the italic style will disappear. But with Rubik, it will look italic again.

One more thing I tried – I changed font family on the editor, but Mozilla still getting font from website default settings, ignoring font I pointed(not cache, tried from new devices + cleared cache). Also what I tried, I added manual style via custom css tab http://prntscr.com/w5gyil, but Mozilla browsers also ignoring this(but the class is there http://prntscr.com/w5gzbu).

So looks like some font bug or smth, can you please check this one?

Thanks in advance!

The page I need help with: [log in to see the link]