spark scroll doesn't work when inside parallax wrapper.

[Jascha-Sundaresan]

When trying the demo from here:
http://keithclark.co.uk/articles/pure-css-parallax-websites/

animations stop working when inside a tag w/ these stylings:

.parallax {
height: 500px; /* fallback for older browsers */
height: 100vh;
overflow-x: hidden;
overflow-y: auto;
-webkit-perspective: 300px;
perspective: 300px;
-webkit-perspective-origin-x: 100%;
perspective-origin-x: 100%;
}