Ruoyi-Flask-admin/app/static/jslib/jquery-easyui-1.3.4/themes/gray/combobox.css

.combobox-item,
.combobox-group {
  font-size: 12px;
  padding: 3px;
  padding-right: 0px;
}
.combobox-gitem {
  padding-left: 10px;
}
.combobox-group {
  font-weight: bold;
}
.combobox-item-hover {
  background-color: #e2e2e2;
  color: #000000;
}
.combobox-item-selected {
  background-color: #0092DC;
  color: #fff;
}