dabblet.css

/* Pounding heart animation */

@keyframes pound {
	to { transform: scale(1.4); }
}

.heart {
	display: inline-block;
	font-size: 150px;
	color: #e00;
	animation: pound .25s infinite alternate;
	transform-origin: center;
}

body { text-align: center; }

dabblet.html

<div class="heart">&#x2665;</div>

dabblet.js

// alert('Hello world!');

settings.json

{"view":"split","fontsize":"100","seethrough":"","prefixfree":"1","page":"css"}