Ruoyi-Flask-admin/app/static/jslib/jquery-easyui-1.3.4/themes/bootstrap/menubutton.css

.m-btn-downarrow {
  display: inline-block;
  width: 16px;
  height: 16px;
  line-height: 16px;
  font-size: 12px;
  _vertical-align: middle;
}
a.m-btn-active {
  background-position: bottom right;
}
a.m-btn-active span.l-btn-left {
  background-position: bottom left;
}
a.m-btn-plain-active {
  background: transparent;
  padding: 0 5px 0 0;
  border-width: 1px;
  border-style: solid;
  -moz-border-radius: 5px 5px 5px 5px;
  -webkit-border-radius: 5px 5px 5px 5px;
  border-radius: 5px 5px 5px 5px;
}
.m-btn-downarrow {
  background: url('images/menu_arrows.png') no-repeat 2px center;
}
a.m-btn-plain-active {
  border-color: #ddd;
  background-color: #e6e6e6;
  color: #00438a;
}