.x-treenode-expand {
    background: transparent url('/webroot/scripts/css/tree1.jpg') no-repeat scroll left center;
    padding-left: 40px; 
}
.x-treenode-unexpand {
    background: transparent url('/webroot/scripts/css/tree2.jpg') no-repeat scroll left center;
    padding-left: 40px;
}
.x-text {
    color: #FFFFFF;
}