There's a bug in the mechanism that checks uploaded Custom CSS as follows.

If a rule mentions "position: static" it somehow causes the parser to remove commas from font-family rules elsewhere. This seems unbelievably unlikely, but it's very repeatable.

1. Starting with a fresh wiki. I used Cornflower Ribbon theme, and moved sidebar to left.

2. Prepare and upload CSS as follows:

/* -------------------------
Buttons: Edit, Page options, Create new
------------------------ */
table#parent div#editlink,
table#parent div#zwMorePageOptions,
td#leftSideBar div#newlink           {
  font-family: Verdana, Arial, sans-serif;   
}

div#abc {
  position: static;
}

Observe that the Verdana etc does not get applied, and that the CSS as delivered from zoho looks like this:

table#parent div#editlink, table#parent div#zwMorePageOptions, td#leftSideBar div#newlink {
font-family: Verdana Arial sans-serif
}
div#abc {  }

Observe lack of commas in the font-family attribute. (In addition to stripping out the position attribute.)

- Graham

My issue tracking id GWZ1019