.admin__menu .level-0.item-top-level > a:before {
    content: url('../images/vr_icon.png');
}

.admin__menu .level-0.item-top-level > a:hover:before {
    /*background-color: white;*/
    /*color: #f7f3eb;*/
    content: url('../images/vr_icon_hover.png');
}