JSFiddle - React, Tailwind, and code Playground

HTML

<div id="popup">
    <h2>Info <span title="click to close" class="close">X</span></h2>
    <div class="content"></div>  
</div>
<form>
    <fieldset>
        <legend>Some Info To Collect</legend>
        <label for="FirstName">First Name</label><input type="text" id="FirstName" name="FirstName" />
        <label for="LastName">Last Name</label><input type="text" id="LastName" name="LastName" />
        <label for="LastName">First Name</label><input type="text" id="LastName" name="LastName" />
        <label for="LastName">First Name</label><input type="text" id="LastName" name="LastName" />
        <label for="LastName">First Name</label><input type="text" id="LastName" name="LastName" />
        <input type="button" value="Click Me" id="btn" />
        </fieldset>
</form>

CSS

#popup{
  position: fixed;
  top: 50%;
  left: 50%;
  margin-top: -100px;
  margin-left: -150px;
 
    border: 1px solid #5C5C5C;    
    height:200px;
    width:300px;
    background-color:#CFC;
    display:none;
}

#popup h2
{
    font-size:1.2em;
    color:#FFF;
    background-color:#090;
    margin:0;
    padding:10px;   
    position:relative;
}

#popup h2>.close
{
    border: solid 1px #FFF;
    padding:2px;
    position:relative;  
    left:220px;
    cursor:pointer;
}

#popup .content
{
    padding:10px;
}

fieldset label
{
    display:inline-block;
    width:30%;
    margin-top:.25em;
}

fieldset input
{
    width:50%;
    margin-top:.25em;
}

JavaScript

//Simulate ajax call
$("#btn").click(function(){
    $("#popup .content").html("Now sit back and relax while we go to work on your behalf, we'll keep you updated with information on our results and if you have any questions then we welcome your calls or emails on xxxxxxxxx or xxxxxxxxxxxxxxx");
    $("#popup").show();
});

//Wire up close functions
$("#popup .close").click(function(){
    $("#popup").hide();
});