Hindergrundfarbe Funktioniert nicht

/* Konten/Ordnerliste */

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
/* Folder pane font */
#folderTree  {
font-size: 14px !important; } 
/* Thread pane font */
#threadTree {
font-size: 15px !important; }
/* Set Line Spacing */
#folderTree > treechildren::-moz-tree-row {
height: 22px !important; }
#threadTree > treechildren::-moz-tree-row {
height: 20px !important; }

/* Konten/Ansichtsspalten Farbe ändern  */

#folderTree  { 
background-color: #f5f5dc !important; -moz-appearance: none !important;  }
#threadTree treechildren {
background-color: #b0e2ff !important;   } 

/* userContent.css *********************************************/
/* Do not remove the @namespace line -- it's required for correct functioning
 * set default namespace to XUL
 */
@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");

    HTML{
    background: azure !important; }   
     
    body {
    background: azure !important; }