Make Dokan Theme Category Menu Scrollable with simple CSS

dokan-theme-cat-menu-scrollable.css

/** Make Dokan theme Category Scroll-able **/
#cat-drop-stack ul{
    height:250px; width:auto;
    overflow:hidden; overflow-y:scroll;
}
#cat-drop-stack ul::-webkit-scrollbar {
      -webkit-appearance: none;
      width: 7px;
}
#cat-drop-stack ul::-webkit-scrollbar-thumb {
      border-radius: 4px;
      background-color:     rgba(0,0,0,.5);
      -webkit-box-shadow: 0 0 1px rgba(255,255,255,.5);
}

#cat-drop-stack ul::-webkit-scrollbar-track {
  box-shadow: inset 0 0 5px grey; 
  border-radius: 3px;
}