JSFiddle - React, Tailwind, and code Playground

HTML

<div class='box'>
    
   
</div>

CSS

.box {
    width: 350px;
    position: relative;
    background: #000;
}

.box::after {
    content: "";
    position: absolute;
    top: 0;
    right: -2px;
    border-style: solid;
    border-width: 0 40px 40px 0;
    border-color: transparent #fff transparent transparent;
    background: #000;
}

.cart {
    position: absolute;
    top: 0;
    right: -4px;
    z-index: 1;
    background: #000;
}