<div class="container">
  <span>My</span>
  <span class="heart">heart</span>
  <span>beats</span>
</div>
@import url(https://fonts.googleapis.com/css?family=Exo+2:400,900,800,700,600,500,300,200,100);

html {
  background-color: #29282E;
  color: White;
}

body {
  font-family: 'Exo 2';
  font-weight: 100;
  text-align: center;
  font-size: 8em;
}

.container {
  position: relative;
  top: 100px;
}

.heart {
  transition: all 0.3s;
  color: #EA4646;
}
var heartuptimer = setInterval(heartup, 200);
function heartup() {
  $(".heart").css("font-weight", "900");
}

var heartdowntimer = setInterval(heartdown, 500);
function heartdown() {
  $(".heart").css("font-weight", "100");
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js