JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://cdn.kendostatic.com/2013.2.716/styles/kendo.common.min.css">
<link rel="stylesheet" href="http://cdn.kendostatic.com/2013.2.716/styles/kendo.default.min.css">
<script src="http://cdn.kendostatic.com/2013.2.716/js/kendo.all.min.js"></script>
<script src="http://demos.kendoui.com/content/shared/js/people.js"></script>
<a class="k-button" id="toggleBtn" href="#">Toggle .k-content class on window content div</a>

<div id="forecast">
    <div id="tabstrip">
        <ul>
            <li class="k-state-active">Paris</li>
            <li>New York</li>
        </ul>
        <div>
             <h2>17<span>&ordm;C</span></h2>

            <p>Rainy weather in Paris.</p>
        </div>
        <div>
             <h2>29<span>&ordm;C</span></h2>

            <p>Sunny weather in New York.</p>
        </div>
    </div>
    <div id="window">
        <div id="positioned-content">Artek Alvar Aalto - Armchair 402Artek Alvar Aalto - Armchair 402Artek Alvar Aalto - Armchair 402Artek Alvar Aalto - Armchair 402Artek Alvar Aalto - Armchair 402Artek Alvar Aalto - Armchair 402Artek Alvar Aalto - Armchair 402Artek Alvar Aalto - Armchair 402Artek Alvar Aalto - Armchair 402Artek Alvar Aalto - Armchair 40</div>
    </div>

CSS

#tabstrip {
    position: absolute;
    top: 50px;
    left: 25px;
    height: 600px;
    width: 900px;
    overflow: auto;
}

#positioned-content {
    position: absolute;
    top: 25px;
    left: 25px;
}

JavaScript

/*
Appending the window to a tab in order to have the window hide when that tab is not active (not interested in handling this through js code)

When the window's content div is appended to a tabstrip it suddenly matches additonal kendo styling rules that are specified with this CSS selector:
".k-tabstrip .k-content, .k-panelbar .k-tabstrip .k-content"

If I remove the .k-content class from the window content div, it renders like I'd expect it to.

Is there a more appropriate way of achieving the same result?

*/

$("#tabstrip").kendoTabStrip();

$("#window").kendoWindow({
    appendTo: '#tabstrip-1',
    width: "600px",
    height: "500px",
    title: "About Alvar Aalto"
});

$(".k-window").css({
    position: 'absolute',
    left: 100,
    top: 100
});

$("#toggleBtn").click(function () {
    $("#window").toggleClass("k-content");
});