CSS

better transition timing functions

.btn {
  /* ease-out */
  transition-timing-function:
    cubic-bezier(0.215, 0.61, 0.355, 1);
  /* ease-in */
  transition-timing-function:
    cubic-bezier(0.75, 0, 1, 1);
  /* ease-in-out */
  transition-timing-function:
    cubic-bezier(0.645, 0.045, 0.355, 1);
  /* ease */
  transition-timing-function:
    cubic-bezier(0.44, 0.21, 0, 1);
}