JSFiddle - React, Tailwind, and code Playground

HTML

<div class="btn">CONTAINER</div>

CSS

.btn {
  color: #31302B;
    background: #FFF;
    margin: 25px;
    padding: 10px 0;
    width: 240px;
    border: 3px solid #31302B;
    font-size: 14px;
    font-weight: bold;
    letter-spacing: 1px;
    text-transform: uppercase;
    border-radius: 2px;
    display: inline-block;
    text-align: center;
    cursor: pointer;
    box-shadow: inset 0 0 0 0 #6a0dad;
	-webkit-transition: all ease 0.8s;
	-moz-transition: all ease 0.8s;
	transition: all ease 0.8s;
}
.btn:hover {
    box-shadow: inset 240px 0 0 0 #6a0dad;
    color: #fff;
}