JSFiddle - React, Tailwind, and code Playground

by Joulence

HTML

<div>
  <ul>
    <li>1</li>
    <li>2</li>
    <li>3</li>
    <li>4</li>
    <li>5</li>
    <li>6</li>
    <li>7</li>
    <li>8</li>
    <li>9</li>
    <li>10</li>
  </ul>
</div>

CSS

div {position: relative}
div * {margin: 0; box-sizing: border-box}

div:after {
  content: "";
  position: absolute;
  -webkit-clip-path: polygon(0 0, 100% 0, 85% 100%, 0% 100%);
  clip-path: polygon(0 0, 100% 0, 85% 100%, 0% 100%);
  background-color: red;
  width: 150px;
  height: 150px;
}

ul {
  position: absolute;
  background-color: green;
  left: 30px;
  top: 50px;
  z-index: 1;
}