XF 1.4 Usergroup CSS not showing in Firefox

[TDUBS]

Hello,

I have run across a few reports of users who have noticed that when using Firefox, their usergroup color is showing orange, when it's supposed to show 'rainbow' text.

Code:

font-weight: bold;
color: #FF6600;
-webkit-text-fill-color: transparent;
-moz-text-fill-color: transparent;
-ms-text-fill-color: transparent;
-o-text-fill-color: transparent;
background: -webkit-gradient(linear, left top, right top, color-stop(0%,#c00000), color-stop(21%,#ff6600), color-stop(40%,#fbb007), color-stop(60%,#009c36), color-stop(80%,#0089cd), color-stop(100%,#5935b9));
background: -moz-gradient(linear, left top, right top, color-stop(0%,#c00000), color-stop(21%,#ff6600), color-stop(40%,#fbb007), color-stop(60%,#009c36), color-stop(80%,#0089cd), color-stop(100%,#5935b9));
background: -ms-gradient(linear, left top, right top, color-stop(0%,#c00000), color-stop(21%,#ff6600), color-stop(40%,#fbb007), color-stop(60%,#009c36), color-stop(80%,#0089cd), color-stop(100%,#5935b9));
background: -o-gradient(linear, left top, right top, color-stop(0%,#c00000), color-stop(21%,#ff6600), color-stop(40%,#fbb007), color-stop(60%,#009c36), color-stop(80%,#0089cd), color-stop(100%,#5935b9));
-webkit-background-clip: text;
-moz-background-clip: text;
-ms-background-clip: text;
-o-background-clip: text;
background-size: 0;
-webkit-background-size: auto;
-moz-background-size: auto;
-ms-background-size: auto;
-o-background-size: 0;

Outcome:
Short Username -

Long Username -

Thanks!