JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://jqwidgets.com/public/jqwidgets/jqx-all.js"></script>
<link rel="stylesheet" href="https://jqwidgets.com/public/jqwidgets/styles/jqx.energyblue.css">
<link rel="stylesheet" href="https://jqwidgets.com/public/jqwidgets/styles/jqx.base.css">
<div id='jqxwindow'>
    <div id="windowHeader">Header</div>
    <div id="windowBody">
        <div id="container">
            <div id="leftblock">a</div>
            <div id="contentblock">b</div>
            <div id="rightblock">c</div>
        </div>
    </div>
</div>

CSS

#container {
    width: 97%; /* to escape scrollbar */
    display: table;
    table-layout: fixed;
    border: 5px solid #ccc;
}

#leftblock {
    width: 50%;
    display: table-cell;
    padding: 10px;
}

#contentblock {
    width: 20px;
    display: table-cell;
    padding: 10px;
    border: 5px solid #ccc;
    border-top: 0;
    border-bottom: 0;
}

#rightblock {
    width: 20%;
    display: table-cell;
    padding: 10px;
}

JavaScript

$('#jqxwindow').jqxWindow({
    height: 800,
    width: 340,
    minHeight: 100,
    minWidth: 200,
    maxHeight: screen.height,
    maxWidth: screen.width,
    isModal: true,
    autoOpen: true,
    resizable: true
});