JSFiddle - React, Tailwind, and code Playground

HTML

<div id="div1">
    <h3>Div #1</h3>
    <code>position: relative;<br/>
        z-index: 5;</code>
</div>

<div id="div2">
    <h3>Div #2</h3>
    <code>position: relative;<br/>
        z-index: 2;</code>
</div>

<div id="div3">
    
    <div id="div4">
        <h3>Div #4</h3>
        <code>position: relative;<br/>
            z-index: 6;</code>
    </div>
    
    <h3>Div #3</h3>
    <code>position: absolute;<br/>
        z-index: 4;</code>
    
    <div id="div5">
        <h3>Div #5</h3>
        <code>position: relative;<br/>
            z-index: 1;</code>
    </div>
    
    <div id="div6">
        <h3>Div #6</h3>
        <code>position: absolute;<br/>
            z-index: 3;</code>
    </div>
    
</div>

CSS

* {
    margin: 0;
}
html {
    padding: 20px;
    font: 12px/20px Arial, sans-serif;
}
div {
    opacity: 0.6;
    position: relative;
}
h1 {
    font: inherit;
    font-weight: bold;
}
#div1, #div2 {
    border: 1px dashed #696;
    padding: 10px;
    background-color: #cfc;
}
#div1 {
    z-index: 5;
    margin-bottom: 190px;
}
#div2 {
    z-index: 2;
}
#div3 {
    z-index: 4;
    opacity: 1;
    position: absolute;
    top: 40px;
    left: 180px;
    width: 330px;
    border: 1px dashed #900;
    background-color: #fdd;
    padding: 40px 20px 20px;
}
#div4, #div5 {
    border: 1px dashed #996;
    background-color: #ffc;
}
#div4 {
    z-index: 6;
    margin-bottom: 15px;
    padding: 25px 10px 5px;
}
#div5 {
    z-index: 1;
    margin-top: 15px;
    padding: 5px 10px;
}
#div6 {
    z-index: 3;
    position: absolute;
    top: 20px;
    left: 180px;
    width: 150px;
    height: 125px;
    border: 1px dashed #009;
    padding-top: 125px;
    background-color: #ddf;
    text-align: center;
}