JSFiddle - React, Tailwind, and code Playground

HTML

<div>release </div>

CSS

div {
    background: deeppink;
    height: 300px;
    width: 300px;
    position: relative;
    text-align: center;
    font: 600 16px sans-serif;
    color: #fff;
    line-height: 27px;
    border: 0;
}

div:after {
    content: "";
    position: absolute;
    bottom: -18px;
    left: 0;
    height: 0;
    width: 0;
    border: solid 15px deeppink;
    border-bottom-color: transparent;
}

div:hover {
    background: purple;
}

div:hover:after {
    border-color: purple;
    border-bottom-color: transparent;
}