JSFiddle - React, Tailwind, and code Playground

HTML

<div class="functionButtonDiv" id="functionButtonDiv">
    <button type="button" class="functionButton">Dummy1</button>
    <button type="button" class="functionButton">Dummy2</button>
</div>

CSS

.functionButton{
  width:60px;
  height:25px;
  border: 1px solid #A3DEF1;
  border-left: none;
  outline:none;
  background: #F2F5FD;
  border-top: 1px solid #A3DEF1; 
}

.functionButton:hover{
  box-shadow: 0 -4px 0 0 #a3def1;
}