JSFiddle - React, Tailwind, and code Playground

HTML

<div class="menu-modules-bg" style="display: block"></div>

CSS

.menu-modules-bg {
    width: 100%;
    height: 100%;
    display: none;
    position: absolute;
    padding-left: 100px;
    top: 0;
    left: 0;
    z-index: 1;
}
.menu-modules-bg:before {
    content: '';
    display: block;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.6);
}