JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
    <div class="line"></div>
</div>

CSS

div.container
{
    width: 300px;
    height: 150px;
    background-color: #aaa;
    padding-top: 150px;
}
div.test
{
    width: 423px;
    height: 1px;
    background-color: #000;
}
div.line
{
    position: relative;
    z-index: 1;
    left: -61px;
    width: 423px;
    height: 1px;
    background-color: #000;
    transform: rotate(45deg);
    -ms-transform: rotate(45deg); /* IE 9 */
    -webkit-transform: rotate(45deg); /* Safari and Chrome */
}