JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://cdn.ractivejs.org/edge/ractive.js"></script>
<main></main>

<script id='template' type='text/ractive'>
    <div
      on-mousemove='set({
        x: event.original.clientX,
        y: event.original.clientY
      })'
      on-mouseleave='set({
        x: "unknown",
        y: "unknown"
      })'
    >
        <p>current mouse position: {{x}} x {{y}}</p>
    </div>
</script>

CSS

body {
    font-family: 'Helvetica Neue', arial, sans-serif;
    font-weight: 200;
    color: #353535;
    margin: 0;
}

h1, h2, h3, h4, h5, h6 {
    font-weight: 200;
}

.error {
    color: #d00;
    font-family: monospace;
}

html, body, main, div {
    width: 100%;
    height: 100%;
    box-sizing: border-box;
}

div {
    padding: 1em;
}

JavaScript

var ractive = new Ractive({
    el: 'main',
    template: '#template',
    data: { x: 'unknown', y: 'unknown' }
});