JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="//code.jquery.com/ui/1.10.3/themes/smoothness/jquery-ui.css">
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<script src="//ajax.googleapis.com/ajax/libs/jqueryui/1.10.3/jquery-ui.min.js"></script>
<button id="button1">Button1</button>
<button id="button2">Button2</button>
<span id="wrapper"><div id="slider"></div></span>

CSS

#button1, #button2 {
    float: right;
}
#wrapper {
    overflow: hidden;
    display: block;
    padding:0 10px;
}
#slider {
    float: left;
    width: 100%;
}

JavaScript

$(document).ready(function () {
    $("#button1").button();
    $("#button2").button();
    $("#slider").slider();
    
    var btnHeight = $('#button1').height(),
        slideHeight = $('#slider').height(),
        buffer = ((btnHeight - slideHeight)/2);
    
    $('#wrapper').height(btnHeight), // set span to button height
    $('#slider').css({'margin-top':buffer}); // set margin accordingly
});