JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://cdn.leafletjs.com/leaflet-0.6.4/leaflet.js"></script>
<link rel="stylesheet" href="http://cdn.leafletjs.com/leaflet-0.6.4/leaflet.css">
<div id = 'map-cont'></div>
<button id = 'height-changer'> 1) Change Height </button>
<button id = 'pos-changer'> 2) Change Position </button>

CSS

#map-cont {
    width: 750px;
    height: 500px;
    border: 1px solid black;
    margin: 30px;
}

.leaflet-popup-content{
    height: 200px;
}

.inner-wrapper{
    background: red;
    width: 300px;
    height: 100px;    
}

.inner-wrapper.full{
    height: 200px;
}

JavaScript

var map = L.map('map-cont').setView([51.505, -0.09], 13);

// add an OpenStreetMap tile layer
L.tileLayer('http://{s}.tile.osm.org/{z}/{x}/{y}.png', {
	attribution: '&amp;copy; &lt;a href="http://osm.org/copyright"&gt;OpenStreetMap&lt;/a&gt; contributors'
}).addTo(map);

// add a marker in the given location, attach some popup content to it and open the popup
var marker = L.marker([51.5, -0.09]).addTo(map)
	.bindPopup('<div class = "inner-wrapper"></div>')
	.openPopup();

document.getElementById('height-changer').addEventListener('click',function(e){
    document.getElementsByClassName('inner-wrapper')[0].className += ' full';
});

document.getElementById('pos-changer').addEventListener('click',function(e){
    marker.setLatLng([51.45, -0.086]);
});