Can't add to custom css file

After updating to Virtue 2.2.3 (I’m using the free version) I lost some code I had added to the Theme Options/custom css file. I tried to follow the directions to update with the new Options panel and also deactivated and reactivated the theme. No luck.

Now it seems that I can’t add any kind of custom code at all to that file – I was trying to add this code to enlarge the social media icons in the top bar:
.topbarmenu ul li a {
font-size: 18px;
}

I also can’t remove [theme-credit] from the Footer Copyright Text (this worked previously also).

Any suggestions? I do love the theme because of the ability to customize. However if it doesn’t save my options I would rather do a child them just to make sure that my changes are saved.

Thanks, alison
website is: https://100friends.org