JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://cdn.sencha.com/ext/gpl/5.1.0/build/packages/ext-theme-classic/build/resources/ext-theme-classic-all.css">
<script src="http://cdn.sencha.com/ext/gpl/5.1.0/build/ext-all.js"></script>
<script src="http://cdn.sencha.com/ext/gpl/5.1.0/build/packages/ext-theme-classic/build/ext-theme-classic.js"></script>

JavaScript

Ext.onReady(function() {

        var Viewport = Ext.create("Ext.container.Viewport", {
            id: "Viewport",
            layout: "border",
            style: 'background: #fff; text-align:left;',
            frame: true,
           
            items: [
                {
                    xtype: "toolbar",
                    height: 35,
                    region: "north",
                    frame: true,
                },
                {
                    xtype: "toolbar",
                    height: 28,
                    region: 'south',
                    html: "<center>ExtJs 5.1</center>",
                },
                {
                    xtype: "panel",
                    height: 500,
                    region: "west",
                    split: true,
                    collapsible: true,
                    autoScroll: true,
                    layout: 'accordion',
                    items: [{ xtype: "panel", title: "Панель №1" }, { xtype: "panel", title: "Панель №12121212" }, { xtype: "panel", title: "Панель №3" }]
                },
                {
                    xtype: "panel",
                    id: "center_panel",
                    region: 'center',
                    autoScroll: true,
                    items: [{
                        xtype: 'window',
                        title: "Window №1",
                        width: 350, height: 250,
                        maximizable: true,
                        resizable: true,
                        border: false,
                        layout: 'border',
                        autoShow: true,
                        constrain: true,
                        x: 0, 
                        y: 0
                    }]
                }

            ]
        });
    
});