JSFiddle - React, Tailwind, and code Playground

HTML

<div id="one">
    <div id="overlay"></div>
</div>
<div id="two">
    <a href="#" id="link">test</a>
</div>

CSS

#one{
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 999;
}
#two{
    position: relative;
    z-index: 9;
    width: 200px;
    height: 200px;
    background: red;
}
#link{
    position: relative;
    z-index: 9999999;
}