Take a look for this in your css (its around line 177 in the demo) –
a,
button,
input[type="button"],
input[type="reset"],
input[type="submit"] {
-webkit-transition: all 0.1s ease-in-out;
-moz-transition: all 0.1s ease-in-out;
-ms-transition: all 0.1s ease-in-out;
-o-transition: all 0.1s ease-in-out;
transition: all 0.1s ease-in-out;
}<!--formatted-->
It’s set at the lowest speed, but you can increase it if you want to use it.