JSFiddle - React, Tailwind, and code Playground

HTML

<div>
<div class="center">
    <button type="button" class="btn">☰</button>
</div>
</div>

CSS

body {
    background: #222;
}

.center {
    width: 100px;
    margin: 50px auto;
}

.btn {
  background-color: #222;
  border: 1px solid #3A3A3A;
  color: #D3D3D3;
  width: 42px;
  margin-left: 42px;
  font-size: 23px;
  height: 34px;
  transition: color 0.45s;
  transition: border 0.45s;
}

button.btn:hover {
  color: #2978E0;
  border: 1px solid #61A5FF;
}