Here's an example of a simple CSS gradient: Code: background:-webkit-gradient( linear, left top, left bottom, color-stop(0.05, #ededed), color-stop(1, #dfdfdf) ); background:-moz-linear-gradient( center top, #ededed 5%, #dfdfdf 100% ); filter:progid:DXImageTransform.Microsoft.gradient(startColorstr='#ededed', endColorstr='#dfdfdf'); background-color:#ededed; As far as I'm aware XenForo creates browser specific CSS, for example one can use: Code: border-radius: 5px; And XenForo will convert it to (as far as I'm aware): Code: border-radius: 5px; -webkit-border-radius: 5px; -moz-border-radius: 5px; -o-border-radius: 5px; The problem is that IE9 handles filter: without an issue, IE10 requires -ms-, especially for gradients. I have no issue using this for non XF content but it just simply doesn't appear to work on XenForo. I tested this by creating a simple HTML page and using the same CSS as I've used within XenForo - HTML page works fine but XF doesn't. Is this an issue or am I missing something somewhere? I've tried the CSS in EXTRA.css as well as in the extra area within the style configuration section.