Add this css in your active class for css arrow
.up-arrow {
position: absolute;
transform: rotate(-45deg);
display: inline-block;
width: 20px;
height: 20px;
z-index: 10;
border-top: 1px solid #c1c1c1;
border-right: 1px solid #c1c1c1;
background-position-x: center;
background: #eeeeee;
margin-top: 7px;
margin-left: 5px;
}
Below image for menu item with arrow