Floating Sticky Sidebar Menu

HTML

<div class='sidebar'>I'm a sidebar</div>
<div style="height: 2000px">foo</div>

CSS

.stickysidebar {
   width: 50px;
   height: 90px;
   position: fixed;
   right: 0px;
   top: 200px;
   border: 1px solid black;
   }
   
   .stickysidebar:hover{
     width: 100px;
   }