JSFiddle - React, Tailwind, and code Playground

by kougiland

HTML

<div class="octagon"></div>

CSS

.octagon{
    width: 100px;
    height: 100px;
    background: #cd1d63;
    margin: 10px 0 0 40px;
}
.octagon:before {
    content: "";
    position: absolute;
    border-bottom: 30px solid #cd1d63;
    border-left: 30px solid #fff;
    border-right: 30px solid #fff;
    width: 40px;
    height: 0;
}
.octagon:after {
    content: "";
    position: absolute;
    border-top: 30px solid #cd1d63;
    border-left: 30px solid #fff;
    border-right: 30px solid #fff;
    width: 40px;
    margin: 70px 0 0 0;
    height: 0;
}