XF 1.4 Custom background for a group

[Deleted member 10469]

Hello, this code don't work, why please ?

html {
    background: url('@imagePath/xenforo/witcher/bg-header.jpg') center 25px no-repeat black;
     <xen:if is="{xen:helper ismemberof, $visitor, '2'}">
        background: red !important;
     </xen:if>
}

Red background is not displayed for registred members.