JSFiddle - React, Tailwind, and code Playground

HTML

<!doctype html>
<title>Задание 1</title>
<div>
    Рабочий эскиз
</div>

CSS

div {
    background: #f0f0f0;
    margin: 20px;
    position: relative;
    border: 1px solid #000;
    padding: 11px;
}
div::before {
    position: absolute;
    top: -16px;
    bottom: -16px;
    right: -1px;
    left: -1px;
    content: "";
    border: solid #000;
    border-width: 0 1px;
    z-index: -1;
}