animate.css/source/attention_seekers/pulse.css

/* originally authored by Nick Pettit - https://github.com/nickpettit/glide */

@keyframes pulse {
    0% { transform: scale(1); }
	50% { transform: scale(1.1); }
    100% { transform: scale(1); }
}

.pulse {
	animation-name: pulse;
}