JSFiddle - React, Tailwind, and code Playground
HTML
<div id='infobutton'>Click Me</div>
<div id='bg'></div>
<div id='infobox'></div>
<div class='displaybox'></div>
<div class='displaybox'></div>
<div class='displaybox'></div>
<div class='displaybox'></div>
<div class='displaybox'></div>
<div class='displaybox'></div>
<div class='displaybox'></div>
CSS
#infobox {
position:absolute;
width:100px;
height:150px;
top:100px;
left:50%;
z-index:2;
margin-left:-50px;
display:none; border:1px solid black; background-color:#FFFFFF;
}
#bg {
position:absolute;
background-color:#000000; opacity:0.4;
filter:alpha(opacity=40);
top:0; left:0; width:100%; display:none; min-height:100%; z-index:1;
}
.displaybox {
display:block; border:1px solid black; background-color:green; width:200px; height:200px;
}
#infobutton {
border:1px solid black; width:100px; padding:5px; display:block; cursor:pointer;
}